)בטיחות )(מידע בטיחות החמרה (מידע על החמרה הודעה על הודעה (alonim.urgent@moh.health.gov.il :(לשלוח ל 2152 במאי51 :תאריך Methadone 5% :שם תכשיר באנגלית 105 67 29097 :מספר רישום מעבדות רפא בע"מ:שם בעל הרישום . כחול=שינוי מקום, ירוק=מחיקה, צהוב=הוספה:השינויים בעלון מסומנים בצבע לרופא עלון לרופא בבעלון טקסט חדש טקסט נוכחי Active ingredient: Methadone HCl Concentrated Active ingredient: Methadone HCl Solution 50 mg/ml Concentrated Solution 50 mg/ml To be diluted before administration. The solution To be diluted before administration. פרק בעלון COMPOSITION should be diluted by the pharmacist to the requested concentration and volume into a new Inactive Ingredients: Methyl paraben, bottle, according to the physician’s instructions. propyl paraben, purified water. Inactive Ingredients: Methyl paraben, propyl paraben, purified water. Deaths, cardiac and respiratory, have been Deaths, cardiac and respiratory, have BLACK BOX reported during initiation and conversion of pain been reported during initiation and WARNING patients to methadone treatment from treatment conversion of pain patients to methadone with other opioid agonists and during initiation of treatment from treatment with other opioid methadone treatment for opioid dependence. In agonists. It is critical to understand the some cases, drug interactions with other drugs, pharmacokinetics of methadone when both licit and illicit, have been suspected. converting patients from other opioids. However, in other cases, deaths appear to have Particular vigilance is necessary during occurred due to the respiratory or cardiac effects treatment initiation, during conversion of methadone and too-rapid titration without from one opioid to another, and during appreciation for the accumulation of methadone dose titration. over time. It is critical to understand the Respiratory depression is the chief hazard pharmacokinetics of methadone when converting associated with methadone hydrochloride patients from other opioids. Particular vigilance is administration. Methadone’s peak necessary during treatment initiation, during respiratory depressant effects typically conversion from one opioid to another, and during occur later, and persist longer than its dose titration. Patients must also be strongly peak analgesic effects, particularly in the cautioned against self-medicating with CNS early dosing period. These characteristics depressants during initiation of methadone can contribute to cases of iatrogenic treatment. overdose, particularly during treatment Respiratory depression is the chief hazard initiation and dose titration. 1 associated with methadone hydrochloride In addition, cases of QT interval administration. Methadone’s peak respiratory prolongation and serious arrhythmia depressant effects typically occur later, and (torsades de pointes) have been observed persist longer than its peak analgesic effects, during treatment with methadone. Most particularly in the early dosing period. These cases involve patients being treated for characteristics can contribute to cases of pain with large, multiple daily doses of iatrogenic overdose, particularly during treatment methadone, although cases have been initiation and dose titration. reported in patients receiving doses In addition, cases of QT interval prolongation and commonly used for maintenance serious arrhythmia (torsades de pointes) have treatment of opioid addiction. been observed during treatment with methadone. Methadone treatment for analgesic Most cases involve patients being treated for pain therapy in patients with acute or chronic with large, multiple daily doses of methadone, pain should only be initiated if the although cases have been reported in patients potential analgesic or palliative care receiving doses commonly used for maintenance benefit of treatment with methadone is treatment of opioid addiction. considered and outweighs the risks. Methadone treatment for analgesic therapy in patients with acute or chronic pain should only be initiated if the potential analgesic or palliative care benefit of treatment with methadone is considered and outweighs the risks. Known hypersensitivity to methadone or to any Known hypersensitivity to methadone. CONTRA- other ingredient in this preparation. Methadone is contraindicated in any INDICATIONS Methadone is contraindicated in any situation situation where opioids are where opioids are contraindicated such as: contraindicated such as: patients with patients with respiratory depression (in the respiratory depression (in the absence of absence of resuscitative equipment or in resuscitative equipment or in unmonitored unmonitored settings), and in patients with acute settings), and in patients with acute bronchial asthma or hypercardia. bronchial asthma or hypercardia. Methadone is contraindicated in any patient who Methadone is contraindicated in any has or is suspected of having a paralytic ileus. patient who has or is suspected of having a paralytic ileus. Concentrated solution. Concentrated solution. WARNINGS – Do not dispense the medicine to the patient in this Do not dispense the medicine to the (BLACK BOX) bottle. patient in this bottle. The solution should be diluted by the pharmacist The solution should be diluted by the to the requested concentration and volume into a pharmacist to the requested concentration new bottle, according to the physician’s and volume into a new bottle, according to instructions. the physician’s instructions. For oral administration only. The preparation must not be injected. 2 Respiratory depression, Incomplete Cross- Respiratory depression, Incomplete tolerance, and Iatrogenic overdose Cross-tolerance, and Iatrogenic overdose Respiratory depression is the chief hazard Respiratory depression is the chief hazard associated with methadone hydrochloride associated with methadone hydrochloride administration. Methadone’s peak respiratory administration. Methadone’s peak depressant effects typically occur later, and respiratory depressant effects typically persist longer than its peak analgesic effects, occur later, and persist longer than its particularly during the initial dosing period. These peak analgesic effects, particularly during characteristics can contribute to cases of the initial dosing period. These iatrogenic overdose, particularly during treatment characteristics can contribute to cases of initiation or dose titration. Respiratory depression iatrogenic overdose, particularly during is of particular concern in elderly or debilitated treatment initiation or dose titration. patients as well as in those suffering from conditions accompanied by hypoxia or Patients tolerant to other opioids may be hypercapnia when even moderate therapeutic incompletely tolerant to methadone. doses may dangerously decrease pulmonary Incomplete cross-tolerance is of particular ventilation. concern for patients tolerant to other mu- Methadone should be used with extreme caution opioid agonists who are being converted in patients with conditions accompanied by to treatment with methadone, thus making hypoxia, hypercapnia, or decreased respiratory determination of dosing during opioid reserve such as: with acute asthma, chronic treatment conversion complex. Deaths obstructive pulmonary disease or cor pulmonale, , have been reported during conversion and with preexisting respiratory depression, from chronic, high-dose treatment with severe obesity, sleep apnea syndrome, other opioid agonists. myxedema, kyphoscoliasis, and CNS depression Therefore, it is critical to understand the or coma. In these patients even usual therapeutic pharmacokinetics of methadone when doses of narcoticsmethadone may decrease converting patients from other opioids. A respiratory drive while simultaneously increasing high dose of “opioid tolerance” does not airway resistance to the point of apnea. eliminate the possibility of methadone Alternative, non-opioid analgesics should be overdose, iatrogenic or otherwise. considered, and Methadone should be used at the lowest effective dose and only under careful Drug abuse and dependence medical supervision. Methadone is, a mu-agonist opioid with an abuse liability similar to other opioid Incomplete Cross-tolerance between Methadone agonists. Methadone and other opioids and other Opioids used in analgesia can be abused and are Patients tolerant to other opioids may be subject to criminal diversion. Abuse of incompletely tolerant to methadone. Incomplete methadone poses a risk of overdose and cross-tolerance is of particular concern for death. This risk is increased with patients tolerant to other mu-opioid agonists who concurrent abuse of methadone with are being converted to treatment with methadone, alcohol and other substances. In addition, 3 WARNINGS thus making determination of dosing during opioid parenteral drug abuse is commonly treatment conversion complex. Deaths have been associated with transmission of infectious reported during conversion from chronic, high- diseases such as hepatitis and HIV. dose treatment with other opioid agonists. Drug addiction is characterized by Therefore, it is critical to understand the compulsive use, use for non-medical pharmacokinetics of methadone when converting purposes, and continued use despite patients from other opioids. A high dose of “opioid harm or risk of harm. Drug addiction is a tolerance” does not eliminate the possibility of treatable disease, utilizing a multi- methadone overdose, iatrogenic or otherwise. disciplinary approach, but relapse is common. Drug abuse and dependence “Drug-seeking” behavior is very common Methadone is, a mu-agonist opioid with an abuse in addicts and drug abusers. Drug- liability similar to other opioid agonists. seeking tactics include emergency calls or Methadone and other opioids used in analgesia visits near the end of office hours, refusal can be abused and are subject to criminal to undergo appropriate examination, diversion. Abuse of methadone poses a risk of testing or referral, repeated claims of lost overdose and death. This risk is increased with prescriptions, tampering with prescriptions concurrent abuse of methadone with alcohol and and reluctance to provide prior medical other substances. In addition, parenteral drug records or contact information for other abuse is commonly associated with transmission treating physician(s). “Doctor shopping” of infectious diseases such as hepatitis and HIV. (visiting multiple prescribers) to obtain Drug addiction is characterized by compulsive additional prescriptions is common among use, use for non-medical purposes, and continued drug abusers and people suffering from use despite harm or risk of harm. Drug addiction untreated addiction. However, it should be is a treatable disease, utilizing a multi-disciplinary important to note that preoccupation with approach, but relapse is common. achieving adequate pain relief can be “Drug-seeking” behavior is very common in appropriate behavior in a patient with poor addicts and drug abusers. Drug-seeking tactics pain control. include emergency calls or visits near the end of office hours, refusal to undergo appropriate Tolerance and Physical Dependence examination, testing or referral, repeated claims of Abuse and addiction are separate and lost prescriptions, tampering with prescriptions distinct from physical dependence and and reluctance to provide prior medical records or tolerance. Physicians should be aware contact information for other treating physician(s). that addiction may not be accompanied by “Doctor shopping” (visiting multiple prescribers) to concurrent tolerance and symptoms of obtain additional prescriptions is common among physical dependence in all addicts. In drug abusers and people suffering from untreated addition, abuse of opioids can occur in the addiction. However, it should be important to note absence of true addiction and is that preoccupation with achieving adequate pain characterized by misuse for non-medical relief can be appropriate behavior in a patient with purposes, often in combination with other poor pain control. psychoactive substances. Methadone, like 4 other opioids, has been diverted for nonTolerance and Physical Dependence medical use. Careful record-keeping of Tolerance is the need for increasing doses of prescribing information, including quantity, opioids to maintain a defined effect such as frequency, andrenewal requests is analgesia (in the absence of disease progression strongly advised. or other external factors). Physical dependence is Proper assessment of the patient, proper manifested by withdrawal symptoms after abrupt prescribing practices, periodic re- discontinuation of a drug or upon administration of evaluation of therapy, and proper an antagonist. dispensing and storage are appropriate Physical dependence is expected during opioid measures that help to limit abuse of opioid agonist therapy of opioid addiction. drugs. Physical dependence and/or tolerance are not If methadone is abruptly discontinued in a unusual during chronic opioid therapy. physically dependent patient, an Abuse and addiction are separate and distinct abstinence syndrome may occur. The from physical dependence and tolerance. opioid abstinence or withdrawal syndrome Physicians should be aware that addiction may is characterized by some or all of the not be accompanied by concurrent tolerance and following: restlessness, symptoms of physical dependence in all addicts. lacrimation,rhinorrhea, yawning, In addition, abuse of opioids can occur in the perspiration, chills, myalgia, and absence of true addiction and is characterized by mydriasis. Other symptoms also may misuse for non-medical purposes, often in develop, including irritability, anxiety, combination with other psychoactive substances. backache, joint pain, weakness, Methadone, like other opioids, has been diverted abdominal cramps, insomnia, nausea, for non-medical use. Careful record-keeping of anorexia, vomiting, diarrhea, or increased prescribing information, including quantity, blood pressure, respiratory rate, or heart frequency, andrenewal requests is strongly rate. advised. In general, chronically administered Proper assessment of the patient, proper methadone should not be abruptly prescribing practices, periodic re-evaluation of discontinued therapy, and proper dispensing and storage are However, most patients who receive appropriate measures that help to limit abuse of opiates for medical reasons do not opioid drugs. develop dependence syndromes. If methadone is abruptly discontinued in a Infants born to mothers physically physically dependent patient, an abstinence dependent on opioids may also be syndrome may occur. The opioid abstinence or physically dependent and may exhibit withdrawal syndrome is characterized by some or respiratory difficulties and withdrawal all of the following: restlessness, symptoms. lacrimation,rhinorrhea, yawning, perspiration, chills, myalgia, and mydriasis. Other symptoms Asthma and other Respiratory Conditions also may develop, including irritability, anxiety, Methadone should be used with extreme backache, joint pain, weakness, abdominal caution in patients with acute asthma, 5 cramps, insomnia, nausea, anorexia, vomiting, chronic obstructive pulmonary disease or diarrhea, or increased blood pressure, respiratory cor pulmonale, a substantially decreased rate, or heart rate. respiratory reserve, and with preexisting In general, chronically administered methadone respiratory depression, hypoxia or should not be abruptly discontinued hypercapnia, severe obesity, sleep apnea However, most patients who receive opiates for syndrome, myxedema ,kyphoscoliasis, medical reasons do not develop dependence and CNS depression or coma. In these syndromes. patients even therapeutic doses of Infants born to mothers physically dependent on narcotics may decrease respiratory drive opioids may also be physically dependent and while simultaneously increasing airway may exhibit respiratory difficulties and withdrawal resistance to the point of apnea. symptoms. Asthma and other Respiratory Conditions Head Injury and Increased Intracranial Methadone should be used with extreme caution Pressure in patients with acute asthma, chronic obstructive The respiratory depressant effects of pulmonary disease or cor pulmonale, a methadone and its capacity to elevate substantially decreased respiratory reserve, and cerebrospinal fluid pressure may be with preexisting respiratory depression, hypoxia or markedly exaggerated in the presence of hypercapnia, severe obesity, sleep apnea increased intracranial pressure. syndrome, myxedema ,kyphoscoliasis, and CNS Furthermore, narcotics produce side depression or coma. In these patients even effects that may obscure the clinical therapeutic doses of narcotics may decrease course of patients with head injuries. In respiratory drive while simultaneously increasing such patients, methadone must be used airway resistance to the point of apnea. with caution and only if it is deemed essential. Head Injury and Increased Intracranial Pressure The respiratory depressant effects of methadone Acute Abdominal Conditions and its capacity to elevate cerebrospinal fluid The administration of opioids may pressure may be markedly exaggerated in the obscure the diagnosis or clinical course of presence of head injury, other intracranial lesions patients with acute abdominal conditions. or a pre-existing increased in intracranial pressure. Furthermore, narcotics produce side Hypotension effects that may obscure the clinical course of Hypotension may result in the patients with head injuries. In such patients, postoperative patient, or in any individual methadone must be used with caution and only if whose ability to maintain blood pressure it is deemed essential. is compromised by hypovolemia or Acute Abdominal Conditions concurrent administration of The administration of opioids may obscure the phenothiazines or general anesthetics. diagnosis or clinical course of patients with acute Narcotics may produce orthostatic abdominal conditions. hypotension in ambulatory patients. Hypotension 6 Hypotension may result in the postoperative Cardiac Conduction Effects patient, or in any individual whose ability to Laboratory studies, both in vivo and in maintain blood pressure is compromised by vitro, have demonstrated that methadone hypovolemia or concurrent administration of inhibits cardiac potassium channels and phenothiazines or general anesthetics. Narcotics prolongs the QT interval. Cases of QT may produce orthostatic hypotension in interval prolongation and serious ambulatory patients. arrhythmia (torsades de pointes) have Cardiac Conduction Effects been observed during treatment with Laboratory studies, both in vivo and in vitro, have methadone. These cases appear to be demonstrated that methadone inhibits cardiac more commonly associated with, but not potassium channels and prolongs the QT interval. limited to, higher dose treatment (> 200 Cases of QT interval prolongation and serious mg/day). Most cases involve patients arrhythmia (torsades de pointes) have been being treated for pain with large, multiple observed during treatment with methadone. daily doses of methadone, although cases These cases appear to be more commonly have been reported in patients receiving associated with, but not limited to, higher dose doses commonly used for maintenance treatment (> 200 mg/day). Most cases involve treatment of opioid addiction. In most of patients being treated for pain with large, multiple the cases seen at typical maintenance daily doses of methadone, although cases have doses, concomitant medications and/or been reported in patients receiving doses clinical conditions such as hypokalemia commonly used for maintenance treatment of were noted as contributing factors. opioid addiction. In most of the cases seen at However, the evidence strongly suggests typical maintenance doses, concomitant that methadone possesses the potential medications and/or clinical conditions such as for adverse cardiac conduction effects in hypokalemia were noted as contributing factors. some patients. However, the evidence strongly suggests that Methadone should be administered with methadone possesses the potential for adverse particular caution to patients already at cardiac conduction effects in some patients. risk for development of prolonged QT Methadone should be administered with particular interval (e.g., cardiac hypertrophy, caution to patients already at risk for development concomitant diuretic use, hypokalemia, of prolonged QT interval (e.g., cardiac hypomagnesemia). Careful monitoring is hypertrophy, concomitant diuretic use, recommended when using methadone in hypokalemia, hypomagnesemia). Careful patients with a history of cardiac monitoring is recommended when using conduction abnormalities, those taking methadone in patients with a history of cardiac medications affecting cardiac conduction, conduction abnormalities, those taking and in other cases where history or medications affecting cardiac conduction, and in physical exam suggest an increased risk other cases where history or physical exam of dysrhythmia. QT prolongation has also suggest an increased risk of dysrhythmia. QT been reported in patients with no prior prolongation has also been reported in patients cardiac history who have received high with no prior cardiac history who have received doses of methadone. Patients developing 7 high doses of methadone. Patients developing QT QT prolongation while on methadone prolongation while on methadone treatment treatment should be evaluated for the should be evaluated for the presence of presence of modifiable risk factors, such modifiable risk factors, such as concomitant as concomitant medications with cardiac medications with cardiac effects, drugs which effects, drugs which might cause might cause electrolyte abnormalities, and drugs electrolyte abnormalities, and drugs which which might act as inhibitors of methadone might act as inhibitors of methadone metabolism. For use of methadone to treat pain, metabolism. For use of methadone to the risk of QT prolongation and development of treat pain, the risk of QT prolongation and dysrhythmias should be weighed against the development of dysrhythmias should be benefit of adequate pain management and the weighed against the benefit of adequate availability of alternative therapies. pain management and the availability of Methadone treatment for analgesic therapy in alternative therapies. patients with acute or chronic pain should only be Methadone treatment for analgesic initiated if the potential analgesic or palliative care therapy in patients with acute or chronic benefit of treatment with methadone has been pain should only be initiated if the considered to outweigh the risk of QT potential analgesic or palliative care prolongation that has been reported with high benefit of treatment with methadone has doses of methadone. been considered to outweigh the risk of The potential risks of methadone, including the QT prolongation that has been reported risk of life-threatening arrhythmias, should be with high doses of methadone. weighed against the risks of discontinuing The use of methadone in patients already methadone treatment. In the patient being treated known to have a prolonged QT interval for opiate dependence with methadone has not been systematically studied. In maintenance therapy, these risks include a very using methadone an individualized benefit high likelihood of relapse to illicit drug use to risk assessment should be carried out following methadone discontinuation. and should include evaluation of patient The use of methadone in patients already known presentation and complete medical to have a prolonged QT interval has not been history. For patients judged to be at risk, systematically studied. The potential risks of careful monitoring of cardiovascular methadone should be weighed against the status, including QT prolongation and substantial morbidity and mortality associated with dysrhythmias should be performed. untreated opioid addiction. In using methadone an individualized benefit to GENERAL risk assessment should be carried out and should When treating pain, methadone given on include evaluation of patient presentation and a fixed-dose schedule may have a narrow complete medical history. For patients judged to therapeutic index in certain patient be at risk, careful monitoring of cardiovascular populations, especially when combined status, including QT prolongation and with other drugs, and should be reserved dysrhythmias should be performed. for cases where the benefits of opioid analgesia with methadone outweigh the 8 GENERAL known potential risks of cardiac When treating pain, methadone given on a fixed- conduction abnormalities, respiratory dose schedule may have a narrow therapeutic depression, altered mental states and index in certain patient populations, especially postural hypotension. Methadone should when combined with other drugs, and should be be used with caution in elderly and reserved for cases where the benefits of opioid debilitated patients; patients who are analgesia with methadone outweigh the known known to be sensitive to central nervous potential risks of cardiac conduction system depressants, such as those with abnormalities, respiratory depression, altered cardiovascular, pulmonary, renal, or mental states and postural hypotension. hepatic disease; and in patients with Methadone should be used with caution in elderly comorbid conditions or concomitant and debilitated patients; patients who are known medications which may predispose to to be sensitive to central nervous system dysrhythmia. depressants, such as those with cardiovascular, pulmonary, renal, or hepatic disease; and in Interactions with other CNS Depressants patients with comorbid conditions or concomitant Patients receiving other opioid analgesics, medications which may predispose to dysrhythmia general anesthetics, phenothiazines, or reduced ventilatory drive. other tranquilizers, sedatives, hypnotics or Interactions with other CNS Depressants other CNS depressants (including alcohol) Patients receiving other opioid analgesics, general concomitantly with methadone may anesthetics, phenothiazines, other tranquilizers, experience respiratory depression sedatives, hypnotics or other CNS depressants ,hypotension, profound sedation, or coma. (including alcohol) concomitantly with methadone may experience respiratory depression, Anxiety – Since methadone as used by hypotension, profound sedation, or coma. tolerant patients at a constant Interactions with Alcohol and Drugs of Abuse maintenance dosage does not act as a Methadone may be expected to have additive tranquilizer, patients who are maintained effects when used in conjunction with alcohol, on this drug will react to life problems and other opioids, or with illicit drugs that cause stresses with the same symptoms of central nervous system depression. Deaths have anxiety as do other individuals. The been reported when methadone has been abused physician should not confuse such in conjunction with benzodiazepines. symptoms with those of narcotic Anxiety – Since methadone as used by tolerant abstinence and should not attempt to treat patients at a constant maintenance dosage does anxiety by increasing the dose of not act as a tranquilizer, patients who are methadone. The action of methadone in maintained on this drug will react to life problems maintenance treatment is limited to the and stresses with the same symptoms of anxiety control of narcotic withdrawal symptoms as do other individuals. The physician should not and is ineffective for relief of general confuse such symptoms with those of narcotic anxiety. abstinence and should not attempt to treat anxiety Acute Pain – Maintenance patients on a by increasing the dose of methadone. The action stable dose of methadone who 9 of methadone in maintenance treatment is limited experience physical trauma, postoperative to the control of narcotic withdrawal symptoms pain or other acute pain cannot be and is ineffective for relief of general anxiety. expected to derive analgesia from their Acute Pain – Maintenance patients on a stable existing dose of methadone. Such dose of methadone who experience physical patients should be administered trauma, postoperative pain or other acute pain analgesics, including opioids, in doses cannot be expected to derive analgesia from their that would otherwise be indicated for non- existing dose of methadone. Such patients should methadone-treated patients with similar be administered analgesics, including opioids, in painful conditions. Due to the opioid doses that would otherwise be indicated for non- tolerance induced by methadone, when methadone-treated patients with similar painful opioids are required for management of conditions. Due to the opioid tolerance induced by acute pain in methadone patients, methadone, when opioids are required for somewhat higher and/or more frequent management of acute pain in methadone patients, doses will often be required than would be somewhat higher and/or more frequent doses will the case for non-tolerant patients. often be required than would be the case for nontolerant patients. Special-Risk Patients Special-Risk Patients Methadone should be given with caution Methadone should be given with caution and the and the initial dose reduced in certain initial dose reduced in certain patients, such as patients, such as the elderly and the elderly and debilitated and those with severe debilitated and those with severe impairment of hepatic or renal function, impairment of hepatic or renal function, hypothyroidism, Addison’s disease, prostatic hypothyroidism, Addison’s disease, hypertrophy, or urethral stricture. The usual prostatic hypertrophy, or urethral stricture. precautions should be observed and the The usual precautions should be possibility of respiratory depression requires observed and the possibility of respiratory added vigilance. depression requires added vigilance. Use in Pregnancy Safety of use in pregnancy has not been Use in Pregnancy established. The placental transfer of narcotics is Safety of use in pregnancy has not been very rapid. Maternal addiction with subsequent established. The placental transfer of neonatal withdrawal is well documented following narcotics is very rapid. Maternal addiction illicit use. Withdrawal symptoms include with subsequent neonatal withdrawal is irritability, excessive crying, yawning, sneezing, well documented following illicit use. increased respiratory rate, tremors, hyperreflexia, Withdrawal symptoms include irritability, fever, vomiting, increased stools and diarrhea. excessive crying, yawning, sneezing, Symptoms usually appear during the first days of increased respiratory rate, tremors, life. hyperreflexia, fever, vomiting, increased Labor and Delivery stools and diarrhea. Symptoms usually As with all opioids, administration of this product appear during the first days of life. to the mother shortly before delivery may result in 10 some degree of respiratory depression in the Labor and Delivery newborn, especially if higher doses are used. As with all opioids, administration of this Methadone is not recommended for obstetric product to the mother shortly before analgesia because its long duration of action delivery may result in some degree of increases the probability of respiratory depression respiratory depression in the newborn, in the newborn. Narcotics with mixed agonist- especially if higher doses are used. antagonist properties should not be used for pain Methadone is not recommended for control during labor in patients chronically treated obstetric analgesia because its long with methadone as they may precipitate acute duration of action increases the probability withdrawal. of respiratory depression in the newborn. Nursing Mothers Narcotics with mixed agonist-antagonist Methadone is secreted into human milk. The properties should not be used for pain safety of breastfeeding while taking oral control during labor in patients chronically methadone is controversial. At maternal oral treated with methadone as they may doses of 10 to 80 mg/day, methadone precipitate acute withdrawal. concentrations from 50 to 570 mcg/L in milk have been reported, which, in the majority of samples, Nursing Mothers were lower than maternal serum drug Methadone is secreted into human milk. concentrations at steady state. The safety of breastfeeding while taking Peak methadone levels in milk occur oral methadone is controversial. At approximately 4 to 5 hours after an oral dose. maternal oral doses of 10 to 80 mg/day, Based on an average milk consumption of 150 methadone concentrations from 50 to 570 mL/kg/day, an infant would consume mcg/L in milk have been reported, which, approximately 17.4 mcg/kg/day which is in the majority of samples, were lower approximately 2 to 3% of the oral maternal dose. than maternal serum drug concentrations Methadone has been detected in very low plasma at steady state. concentrations in some infants whose mothers Peak methadone levels in milk occur were taking methadone. Caution should be approximately 4 to 5 hours after an oral exercised when methadone is administered to a dose. Based on an average milk nursing woman. There have been rare cases of consumption of 150 mL/kg/day, an infant sedation and respiratory depression in infants would consume approximately 17.4 exposed to methadone through breast milk. mcg/kg/day which is approximately 2 to Mothers using methadone should receive specific 3% of the oral maternal dose. Methadone information about how to identify respiratory has been detected in very low plasma depression and sedation in their babies. They concentrations in some infants whose should know when to contact their healthcare mothers were taking methadone. provider or seek immediate medical care. A Women on high dose methadone healthcare provider should weigh the benefits of maintenance, who are already breast breastfeeding against the risks of infant exposure feeding, should be counseled to wean to methadone and possible exposure to other breast-feeding gradually in order to medicines. prevent neonatal abstinence syndrome. 11 Women on high dose methadone maintenance, Methadone-treated mothers considering who are already breast feeding, should be nursing an opioid-naïve infant should be counseled to wean breast-feeding gradually in counseled regarding the presence of order to prevent neonatal abstinence syndrome. methadone in breast milk. Methadone-treated mothers considering nursing Because of the potential for serious an opioid-naïve infant should be counseled adverse reactions in nursing infants from regarding the presence of methadone in breast methadone, a decision should be made milk. whether to discontinue nursing or to Because of the potential for serious adverse discontinue the drug, taking into account reactions in nursing infants from methadone, a the importance of the drug to the mother. decision should be made whether to discontinue In patients being treated for opioid nursing or to discontinue the drug, taking into dependence, this should include weighing account the importance of the drug to the mother. the risk of methadone against the risk of In patients being treated for opioid dependence, maternal illicit drug use. this should include weighing the risk of methadone against the risk of maternal illicit drug Pediatric Use use. Safety and effectiveness in pediatric Pediatric Use patients below the age of 18 years have Safety and effectiveness in pediatric patients not been established. Accidental or below the age of 18 years have not been deliberate ingestion by a child may cause established. Accidental or deliberate ingestion by respiratory depression that can result in a child may cause respiratory depression that can death. Patients and caregivers should be result in death. Patients and caregivers should be instructed to keep methadone in a secure instructed to keep methadone in a secure place place out of the reach of children and to out of the reach of children and to discard unused discard unused methadone in such a way methadone in such a way that individuals other that individuals other than the patient for than the patient for whom it was originally whom it was originally prescribed will not prescribed will not come in contact with the drug. come in contact with the drug. Heroin Withdrawal Heroin Withdrawal ADVERSE During the induction phase of methadone During the induction phase of methadone REACTIONS maintenance treatment, patients are being maintenance treatment, patients are being withdrawn from heroin and may therefore show withdrawn from heroin and may therefore typical withdrawal symptoms, which should be show typical withdrawal symptoms, which differentiated from methadone-induced side should be differentiated from methadone- effects.They may exhibit some or all of the induced side effects.They may exhibit following signs and symptoms associated with some or all of the following signs and acute withdrawal from heroin or other opiates: symptoms associated with acute lacrimation, rhinorrhea, sneezing, yawning, withdrawal from heroin or other opiates: excessive perspiration, goose-flesh, fever, lacrimation, rhinorrhea, sneezing, chilliness alternating with flushing, restlessness, yawning, excessive perspiration, goose- 12 irritability, weakness, anxiety, depression, dilated flesh, fever, chilliness alternating with pupils, tremors, tachycardia, abdominal cramps, flushing, restlessness, irritability, body aches, involuntary twitching and kicking weakness, anxiety, depression, dilated movements, anorexia, nausea, vomiting, diarrhea, pupils, tremors, tachycardia, abdominal intestinal spasms, and weight loss. cramps, body aches, involuntary twitching and kicking movements, anorexia, Initial Administration nausea, vomiting, diarrhea, intestinal The initial methadone dose should be carefully spasms, and weight loss. titrated to the individual. Too rapid titration for the patient's sensitivity is more likely to produce Major Hazards adverse effects. Respiratory depression, apnea, and to a lesser degree, systemic hypotension, Major Hazards circulatory depression, respiratory arrest, Respiratory depression, apnea, and to a lesser shock and cardiac arrest, and death have degree, systemic hypotension, circulatory occurred. depression, respiratory arrest, shock and cardiac arrest, and death have occurred. Most Frequent Lightheadedness, dizziness, sedation, Most Frequent nausea, vomiting, and sweating. These Lightheadedness, dizziness, sedation, nausea, effects are more prominent in ambulatory vomiting, and sweating. These effects are more patients and in those not experiencing prominent in ambulatory patients and in those not severe pain. They can be alleviated by experiencing severe pain. They can be alleviated lowering the dosage. by lowering the dosage. Allergic Allergic Pruritis, urticaria, other skin rashes, Pruritis, urticaria, other skin rashes, diaphoresis, diaphoresis, laryngospasm, edema, and laryngospasm, edema, and rarely, haemorrhagic rarely, haemorrhagic urticaria. urticaria. Central Nervous System Central Nervous System Euphoria, dysphoria, delirium, weakness, Euphoria, dysphoria, delirium, weakness, headache, edema, drowsiness, miosis, headache, edema, drowsiness, miosis, coma, coma, insomnia, agitation, tremor, insomnia, agitation, tremor, seizures, impairment impairment of mental and physical of mental and physical performance, lethargy, performance, lethargy, anxiety fear, anxiety fear, psychic dependence, mood changes, psychic dependence, mood changes, hallucinations, disorientation, confusion, and hallucinations, disorientation, confusion, visual disturbances. Choreic movements have and visual disturbances. Choreic been induced by methadone. movements have been induced by methadone. Cardiovascular 13 Facial flushing, peripheral circulatory collapse, Cardiovascular arrhythmias, bigeminal rhythms, cardiomyopathy, Facial flushing, peripheral circulatory ECG abnormalities, extrasystoles, heart failure, collapse, arrhythmias, bigeminal rhythms, phlebitis, QT interval prolongation, T-wave cardiomyopathy, ECG abnormalities, inversion, torsade de pointes, tachycardia, extrasystoles, heart failure, phlebitis, QT bradycardia, palpitations, hypotension, syncope, interval prolongation, T-wave inversion, ventricular fibrillation. torsade de pointes, tachycardia, bradycardia, palpitations, hypotension, Gastrointestinal syncope. Dry mouth, glossitis, abdominal pain, anorexia, constipation, and biliary tract spasm. Patients Gastrointestinal with chronic ulcerative colitis may experience Dry mouth, glossitis, abdominal pain, increased colonic motility and toxic dilation. anorexia, constipation, and biliary tract Concomitant administration of laxatives may spasm. Patients with chronic ulcerative counteract narcotic-induced constipation. colitis may experience increased colonic motility and toxic dilation. Concomitant Genitourinary administration of laxatives may counteract Ureteral spasm and spasm of vesical sphincters, narcotic-induced constipation. urinary retention or hesitancy, oliguria, antidiuretic effect, reduced libido or potency, amenorrhea. Genitourinary Ureteral spasm and spasm of vesical Haematologic and Lymphatic sphincters, urinary retention or hesitancy, Reversible thrombocytopenia has been described oliguria, antidiuretic effect, reduced libido in opioid addicts with chronic hepatitis. or potency, amenorrhea. Metabolic and Nutritional Haematologic and Lymphatic Hypokalaemia, hypomagnesemia, weight gain. Reversible thrombocytopenia has been described in opioid addicts with chronic Respiratory hepatitis. Pulmonary edema, respiratory depression. Metabolic and Nutritional Other Hypokalaemia, hypomagnesemia, weight Muscular rigidity. gain. Maintenance on a stabilized dose- during prolonged administration of methadone, as in a Respiratory methadone maintenance treatment program, Pulmonary edema, respiratory there is usually a gradual, yet progressive, depression. disappearance of side effects over a period of several weeks. However, constipation and Other sweating often persist. Muscular rigidity. Maintenance on a stabilized dose- during 14 prolonged administration of methadone, as in a methadone maintenance treatment program, there is usually a gradual, yet progressive, disappearance of side effects over a period of several weeks. However, constipation and sweating often persist. Methadone/Alcohol/General Anesthetics/Tricyclic Methadone/Alcohol/General DRUG INTER- Antidepressants/CNS Depressants Anesthetics/Tricyclic ACTIONS Concomitant use may result in increased CNS Antidepressants/CNS Depressants depression, respiratory depression, and Concomitant use may result in increased hypotensive effects. Caution is recommended, CNS depression, respiratory depression, and the dosage of one or both agents should be and hypotensive effects. Caution is reduced. Deaths have been reported when recommended, and the dosage of one or methadone has been abused in conjunction with both agents should be reduced. Deaths benzodiazepines. In addition, some have been reported when methadone has phenothiazines increase, while others decrease, been abused in conjunction with methadone-induced analgesia. benzodiazepines. In addition, some phenothiazines increase, while others Methadone/Anticholinergics decrease, methadone-induced analgesia. Concomitant use may result in increased risk of severe constipation and/or urinary retention. Methadone/Anticholinergics Concomitant use may result in increased Methadone/ Anti-retroviral agents risk of severe constipation and/or urinary Abacavir, amprenavir, efavirenz, nelfinavir, retention. nevirapine, ritonavir,lopinavir+ritonavir combination Methadone/ Anti-retroviral agents Concomitant use of these anti retroviral agents as Concomitant use of anti retroviral agents abacavir, amprenavir, efavirenz, nelfinavir, as abacavir, amprenavir, efavirenz, nevirapine, ritonavir, lopinavir+ritonavir nelfinavir, nevirapine, ritonavir, combination, resulted in increased clearance or lopinavir+ritonavir combination, resulted in decreased plasma levels of methadone. increased clearance or decreased plasma Methadone-maintained patients beginning levels of methadone. Methadone- treatment with these anti-retroviral drugs should maintained patients should be monitored be monitored for evidence of withdrawal effects for evidence of withdrawal effects and and methadone dose should be adjusted methadone dose should be adjusted accordingly. accordingly. Methadone/ Didanosine and Stavudine Experimental evidence demonstrated that Methadone/ Cytochrome P450 methadone decreased the AUC and peak levels In vitro results suggest that methadone 15 for didanosine and stavudine, with a more undergoes hepatic N-demethylation by significant decrease for didanosine. Methadone cytochrome P450 enzymes, principally disposition was not substantially altered. CYP3A4, CYP2B6, CYP2C19 and to a Methadone/Zidovudine lesser extent by CYP2C9 and CYP2D6. Experimental evidence demonstrated that Coadministration ofmethadone with CYP methadone increased the AUC of zidovudine inducers of these enzymes may result in a which could result in toxic effects. more rapid metabolism and potential for decreased effects of methadone, whereas Methadone/ Cytochrome P450 administration with CYP inhibitors may In vitro results suggest that methadone undergoes reduce metabolism and potentiate hepatic N-demethylation by cytochrome P450 methadone’s effects. Although enzymes, principally CYP3A4, CYP2B6, antiretroviral drugs such as efavirenz, CYP2C19 and to a lesser extent by CYP2C9 and nelfinavir, nevirapine, ritonavir, CYP2D6. Coadministration ofmethadone with lopinavir+ritonavir combination are known CYP inducers of these enzymes may result in a to inhibit CYPs, they are shown to reduce more rapid metabolism and potential for the plasma levels of methadone, possibly decreased effects of methadone, whereas due to their CYP induction activity. administration with CYP inhibitors may reduce Therefore, drugs administered metabolism and potentiate methadone’s effects. concomitantly with methadone should be Although antiretroviral drugs such as efavirenz, evaluated for interaction potential; nelfinavir, nevirapine, ritonavir, lopinavir+ritonavir clinicians are advised to evaluate combination are known to inhibit CYPs, they are individual response to drug therapy shown to reduce the plasma levels of methadone, possibly due to their CYP induction activity. Cytochrome P450 Inducers Therefore, drugs administered concomitantly with Methadone-maintained patients beginning methadone should be evaluated for interaction treatment with CYP3A4 inducers should potential; clinicians are advised to evaluate be monitored for evidence of withdrawal individual response to drug therapy. effects and methadone dose should be adjusted accordingly. The following drug Cytochrome P450 Inducers interactions were reported following co- Methadone-maintained patients beginning administration of methadone with inducers treatment with CYP3A4 inducers should be of cytochrome P450 enzymes: monitored for evidence of withdrawal effects and Rifampin – In patients well-stabilized on methadone dose should be adjusted accordingly. methadone, concomitant administration of The following drug interactions were reported rifampin resulted in a marked reduction in following co-administration of methadone with serum methadone levels and a concurrent inducers of cytochrome P450 enzymes: appearance of withdrawal symptoms. Rifampin – In patients well-stabilized on Phenytoin – In a pharmacokinetic study methadone, concomitant administration of with patients on methadone maintenance rifampin resulted in a marked reduction in serum therapy, phenytoin administration (250 mg methadone levels and a concurrent appearance of b.i.d. initially for 1 day followed by 300 mg 16 withdrawal symptoms. QD for 3 to 4 days) resulted in an Phenytoin – In a pharmacokinetic study with approximately 50%reduction in patients on methadone maintenance therapy, methadone exposure and withdrawal phenytoin administration (250 mg b.i.d. initially for symptoms occurred concurrently. Upon 1 day followed by 300 mg QD for 3 to 4 days) discontinuation of phenytoin, the resulted in an approximately 50%reduction in incidence of withdrawal symptoms methadone exposure and withdrawal symptoms decreased and methadone exposure occurred concurrently. Upon discontinuation of increased to a level comparable to that phenytoin, the incidence of withdrawal symptoms prior to phenytoin administration. decreased and methadone exposure increased to St. John’s Wort, Phenobarbital, a level comparable to that prior to phenytoin Carbamazepine - Administration of administration. methadone along with other CYP3A4 St. John’s Wort, Phenobarbital, Carbamazepine - inducers may result in withdrawal Administration of methadone along with other symptoms. CYP3A4 inducers may result in withdrawal symptoms. Cytochrome P450 Inhibitors Since the metabolism of methadone is Cytochrome P450 Inhibitors mediated primarily by CYP3A4 isozyme, Since the metabolism of methadone is mediated coadministration of drugs that inhibit primarily by CYP3A4 isozyme, coadministration of CYP3A4 activity may cause decreased drugs that inhibit CYP3A4 activity may cause clearance of methadone. The expected decreased clearance of methadone. The expected clinical results would be increased or clinical results would be increased or prolonged prolonged opioid effects. Thus, opioid effects. Thus, methadone-treated patients methadone-treated patients coadministered strong inhibitors of CYP3A4, such coadministered strong inhibitors of as azole antifungal agents (e.g., ketoconazole) CYP3A4, such as azole antifungal agents and macrolide antibiotics (e.g., erythromycin), with (e.g., ketoconazole) and macrolide methadone should be carefully monitored and antibiotics (e.g., erythromycin), with dosage adjustment should be undertaken if methadone should be carefully monitored warranted. Some selective serotonin reuptake and dosage adjustment should be inhibitors (SSRIs) (e.g., sertraline, fluvoxamine) undertaken if warranted. Some selective may increase methadone plasma levels up on serotonin reuptake inhibitors (SSRIs) coadministration with methadone and result in (e.g., sertraline, fluvoxamine) may increased opiate effects and/or toxicity. increase methadone plasma levels up on Methadone/ Didanosine and Stavudine coadministration with methadone and Experimental evidence demonstrated that result in increased opiate effects and/or methadone decreased the AUC and peak levels toxicity. for didanosine and stavudine, with a more Methadone/ Didanosine and Stavudine significant decrease for didanosine. Methadone Experimental evidence demonstrated that disposition was not substantially altered. methadone decreased the AUC and peak Methadone/Zidovudine levels for didanosine and stavudine, with 17 Experimental evidence demonstrated that a more significant decrease for methadone increased the AUC of zidovudine didanosine. Methadone disposition was which could result in toxic effects. not substantially altered. Methadone/ Voriconazole Methadone/Zidovudine Repeat dose administration of oral voriconazole Experimental evidence demonstrated that (400mg Q12h for 1 day, then 200mg Q12h for 4 methadone increased the AUC of days) increased the Cmax and AUC of (R)- zidovudine which could result in toxic methadone by 31% and 47%, respectively, in effects. subjects receiving a methadone maintenance Methadone/ Voriconazole dose (30 to 100 mg QD). The Cmax and AUC of Repeat dose administration of oral (S)-methadone increased by 65% and 103%, voriconazole (400mg Q12h for 1 day, then respectively. Increased plasma concentrations of 200mg Q12h for 4 methadone have been associated with toxicity days) increased the Cmax and AUC of including QT prolongation. Frequent monitoring (R)-methadone by 31% and 47%, for adverse events and toxicity related to respectively, in subjects receiving a methadone is recommended during methadone maintenance dose (30 to 100 coadministration. Dose reduction of methadone mg QD). The Cmax and AUC of (S)- may be needed. methadone increased by 65% and 103%, Methadone/ Hydroxyzine respectively. Increased plasma Concomitant use may result in increased concentrations of methadone have been analgesia and sedation. associated with toxicity including QT prolongation. Frequent monitoring for Methadone/ Levallorphan/ Naloxone adverse events and toxicity related to Antagonism of the analgesic, CNS, and methadone is recommended during respiratory depressant effects of methadone may coadministration. Dose reduction of occur, and may precipitate withdrawal symptoms methadone may be needed. in physically dependent patients. The dosage of Methadone/ Hydroxyzine levallorphan, naloxone, naltrexone should be Concomitant use may result in increased carefully titrated when used to treat overdosage in analgesia and sedation. dependent patients. Methadone/ Levallorphan/ Naloxone Methadone/ Other Opioid Drugs Antagonism of the analgesic, CNS, and Additive CNS depressant, respiratory depressant, respiratory depressant effects of and hypotensive effects may occur if two or more methadone may occur, and may opioid agonist analgesics are used concurrently. precipitate withdrawal symptoms in Patients who are addicted to heroin or who are on physically dependent patients. The a methadone maintenance program may dosage of levallorphan, naloxone, experience withdrawal symptoms when given naltrexone should be carefully titrated pentazocine, butorphanol, nalbuphine or when used to treat overdosage in buprenorphine. dependent patients. 18 Methadone/Monoamine Oxidase Inhibitors/ Methadone/ Other Opioid Drugs Furazolidone Desipramine Additive CNS depressant, respiratory Methadone should be used cautiously, and in depressant, and hypotensive effects may reduced dosage, in patients receiving monoamine occur if two or more opioid agonist oxidase inhibitors or furazolidone. It is analgesics are used concurrently. recommended that a small test dose, or several Patients who are addicted to heroin or incremental test doses over a period of several who are on a methadone maintenance hours, should first be administered to permit program may experience withdrawal observation of any interaction. symptoms when given pentazocine, Methadone /Desipramine butorphanol, nalbuphine or Blood levels of desipramine have increased with buprenorphine. concurrent methadone administration. Methadone/Monoamine Oxidase Methadone/ Arrythmogenic agents Inhibitors/ Furazolidone/ Desipramine Extreme caution is necessary when any drug Methadone should be used cautiously, known to have the potential to prolong the QT and in reduced dosage, in patients interval is prescribed in conjunction with receiving monoamine oxidase inhibitors or methadone. Pharmacodynamic interactions may furazolidone. It is recommended that a occur with concomitant use of methadone and small test dose, or several incremental potentially arrythmogenic agents such as class I test doses over a period of several hours, and III antiarrhythmics, some neuroleptics and should first be administered to permit tricyclic antidepressants, and calcium channel observation of any interaction. blockers. Blood levels of desipramine have Caution should also be exercised when increased with concurrent methadone prescribing methadone concomitantly with drugs administration. capable of inducing electrolyte disturbances (hypomagnesemia, hypokalemia) that may Methadone/ Arrythmogenic agents prolong the QT interval. These drugs include Extreme caution is necessary when any diuretics, laxatives, and, in rare cases, drug known to have the potential to mineralocorticoid hormones. prolong the QT interval is prescribed in conjunction with methadone. Methadone/ Neuromuscular Blocking Agents Pharmacodynamic interactions may occur Respiratory depressant effects of neuromuscular with concomitant use of methadone and blocking agents may be additive to central potentially arrythmogenic agents such as respiratory depressant effects of opioid class I and III antiarrhythmics, some analgesics. Caution is recommended when neuroleptics and tricyclic antidepressants, methadone is administered in the immediate post- and calcium channel blockers. operative period to patients who have received a Caution should also be exercised when neuromuscular blocking agent. prescribing methadone concomitantly with Methadone/ Rifampicin/ Phenytoin drugs capable of inducing electrolyte The concurrent administration of rifampicin or disturbances (hypomagnesemia, 19 phenytoin may reduce the plasma levels of hypokalemia) that may prolong the QT methadone to a degree sufficient to produce interval. These drugs include diuretics, withdrawal symptoms. The mechanism is not fully laxatives, and, in rare cases, understood, but may be due to increased hepatic mineralocorticoid hormones. metabolism of methadone. Diagnostic Interference Methadone/ Neuromuscular Blocking Because narcotics may increase biliary tract Agents pressure with resultant increases in plasma Respiratory depressant effects of amylase or lipase, levels may be unreliable for 24 neuromuscular blocking agents may be hours after narcotic administration. additive to central respiratory depressant effects of opioid analgesics. Caution is recommended when methadone is administered in the immediate postoperative period to patients who have received a neuromuscular blocking agent. Methadone/ Rifampicin/ Phenytoin The concurrent administration of rifampicin or phenytoin may reduce the plasma levels of methadone to a degree sufficient to produce withdrawal symptoms. The mechanism is not fully understood, but may be due to increased hepatic metabolism of methadone. Diagnostic Interference Because narcotics may increase biliary tract pressure with resultant increases in plasma amylase or lipase, levels may be unreliable for 24 hours after narcotic administration. Manifestations Manifestations In severe overdosage, apnea, circulatory collapse, In severe overdosage, apnea, circulatory convulsions, cardiopulmonary arrest, and even collapse, convulsions, cardiopulmonary death may occur. The less severely poisoned arrest, and even death may occur. The patient often presents the triad of central nervous less severely poisoned patient often system depression, miosis and respiratory presents the triad of central nervous depression. system depression, miosis and respiratory Serious overdosage is characterized by depression. respiratory depression (a decrease in respiratory Serious overdosage is characterized by 20 OVERDOSAGE rate and/or tidal volume, Cheyne-Stokes respiratory depression, extreme respiration, cyanosis) , extreme somnolence somnolence progressing to stupor or progressing to stupor or coma, constricted pupils, coma, constricted pupils, skeletal muscle skeletal muscle flaccidity, and cold and clammy flaccidity, and cold and clammy skin. skin. Hypotension, bradycardia, hypothermia, Hypotension, bradycardia, hypothermia, pulmonary edema, pneumonia, or shock occurs in pulmonary edema, pneumonia, or shock up to 40% of patients. occurs in up to 40% of patients. Treatment Treatment Primary attention should be given to the Primary attention should be given to the maintenance of adequate respiratory exchange maintenance of adequate respiratory through provision of a patent airway and institution exchange through provision of a patent of assisted or controlled ventilation. If depressed airway and institution of assisted or respiration is associated with muscular rigidity, an controlled ventilation. If depressed intravenous neuromuscular blocking agent may respiration is associated with muscular be required. rigidity, an intravenous neuromuscular After assessing the pulmonary status of the blocking agent may be required. patient, administer a narcotic antagonist After assessing the pulmonary status of (naloxone is the antagonist of choice). Narcotic the patient, administer a narcotic antagonists are specific antidotes for overdosage. antagonist (naloxone is the antagonist of The physician must remember, however, that choice). Narcotic antagonists are specific methadone is a long-acting depressant (36 to 48 antidotes for overdosage. The physician hours), where opioid antagonist act for much must remember, however, that shorter periods (one to three hours). methadone is a long-acting depressant Since the duration of action of most narcotics (36 to 48 hours), where opioid antagonist exceeds that of narcotic antagonists, act for much shorter periods (one to three administration of the antagonist should be hours). repeated to maintain adequate respiration and the Since the duration of action of most patient should be kept under surveillance. Do not narcotics exceeds that of narcotic administer an antagonist in the absence of antagonists, administration of the clinically-significant respiratory or cardiovascular antagonist should be repeated to maintain depression. adequate respiration and the patient In an individual physically dependent on opioids, should be kept under surveillance. Do not the administration of the usual dose of an opioid administer an antagonist in the absence antagonist may precipitate an acute withdrawal of clinically-significant respiratory or syndrome. The severity of this syndrome will cardiovascular depression. depend on the degree of physical dependence Employ oxygen, intravenous fluids, and the dose of the antagonist administered. If vasopressors, and other supportive antagonists must be used to treat serious measures as indicated. In cases of oral respiratory depression in the physically dependent overdose, and where treatment can be patient, the antagonist should be administered instituted within 2 hours following with extreme care and by titration with smaller ingestion, evacuate the stomach by 21 than usual doses of the antagonist. emesis or gastric lavage. Closely observe Intravenously administered naloxone or the patient for a rise in temperature or nalmefene may be used to reverse signs of pulmonary complications that may require intoxication. Because of the relatively short half- institution of antibiotic therapy. life of naloxone as compared with methadone, repeated injections may be required until the status of the patient remains satisfactory. Naloxone may also be administered by continuous intravenous infusion. Employ oxygen, intravenous fluids, vasopressors, and other supportive measures as indicated. In cases of oral overdose, and where treatment can be instituted within 2 hours following ingestion, evacuate the stomach by emesis or gastric lavage. Closely observe the patient for a rise in temperature or pulmonary complications that may require institution of antibiotic therapy. Store below 25°C. SPECIAL Once the bottle is opened, it should be stored PRECAUTIONS below 25°C and the solution can be used within 6 FOR STORAGE months, but no later than the expiration date printed on the package. Bottles of 90 and 200 ml. Bottles of 90 and 200 ml. PRESENTATION 22