HYPNOTIC - SEDATIVE DRUGS Dra. Ma. Shiela C. Guiking Are drugs that belong to a group of agents that depress the CNS in a relatively nonselective dose-dependent fashion, producing progressively calming or drowsiness, sleep, unconsiousness, surgical anesthesia, coma, fatal depression of the respiration and cardiovascular regulation major therapeutic use is to cause sedation (with concomitant relief of anxiety) or to encourage sleep SEDATIVES— drugs capable of producing mild depression; decreased activity; moderate excitement, and emotional calmness - reduce anxiety (anxiolytic) and exert a calming effect with little or no effect on motor or mental functions, degree of CNS depression minimum consistent with therapeutic efficacy HYPNOTICS — drugs that are used primarily to induce sleep - should produce drowsiness and encourage the onset and maintenance of a state of sleep - involves more pronounced depression of the CNS The Benzodiazepines are the most widely used sedative hypnotics. Structures- 1,4, Benzodiazepines-contain a carboxamide group in the 7 – membered heterocyclic ring structure. A substituent in the 7 position, such as a halogen or a nitro group, is required for sedative-hypnotic activity CLASSIFICATION: BENZODIAZEPINES Types: A. Hypnotic Benzodiazepines > Nitrazepam > Flurazepam (Dalmane) B. Anxiolytic Benzodiazepines > > > > > > > > > > > > Alprazolam ( Xanax) Chlordiazepoxide ( Librium ) Chlorazepate ( Tranxene ) Clonazepam ( Klonopin ) Diazepam ( Valium ) Halazepam ( Paxipam ) Lorazepam ( Ativan ) Midazolam ( Versed ) Oxazepam ( Serax ) Prazepam ( Centrax ) Temazepam ( Restoril ) Triazolam ( Halcion ) Triazolam and Alprazolam : Triazolobenzodiazepines Glutethimide, etc : Piperidinediones > Meprobamate : Propanediol carbamates > Barbiturates > Alcohols : Ethanol, Chloral hydrate, Paraldehyde > Cyclic esters > Buspirone : azaspirodecanedione > Zolpidem : Imidazopyridine > Zaleplon : Pyrazolopyrimidine > Beta – blocking drugs > Clonidine > Antipsychotic tranqulizers, tricyclic antidepressant drugs > Antihistaminic agents (hydroxyzine, promethazine) Since they commonly exert marked effects on the Peripheral autonomic nervous system, they are sometimes referred to as “sedative autonomic” drugs PHARMACOKINETICS A. Absorption > to treat anxiety and sleep disorders: given orally > oral absorption may depend on lipophilicity, with plasma peak concentration ranging from 0.5 to 8 hours rapid: triazolam, diazepam, clorazepate slow : oxazepam, lorazepam temazepam > with high lipid-water distribution coefficients in the non-ionized form > essentially completely absorbed > Bioavailability : after intramuscular injection unreliable (except lorazepam and midazolam ) B. Distribution - some reach the systemic circulation only in the form of active metabolite ( prazepam, flurazepam) - rate of transport in blood depends on blood flow, concentration gradients and permeability - rate of entry into CNS depends on lipid solubility - plasma protein binding 60% to over 95% cross the placental barrier and secreted into breast milk PHARMACODYNAMICS: Mechanism of action appear to enhance GABA’s effects without directly activating GABA receptors or opening the associated chloride channels. The enhancement in chloride ion conductance induced by the interaction of benzodiazepines with GABA takes the form of an increase in the frequency of channel opening events Types of Benzodiazepine receptor interactions: 1. AGONISTS facilitate GABA actions, and this occurs at multiple BZ receptor sites in the case of benzodiazepines –> Zolpidem and Zaleplon – selective agonists at the BZ1 receptor subtype 2. ANTAGONISTS – synthetic benzodiazepine derivative FLUMAZENIL, blocks the actions of benzodiazepines and zolpidem but does not antagonize the actions of barbiturates, meprobamate and ethanol 3. INVERSE AGONISTS act as negative allosteric modulators of GABA receptor function ( B- carbolines eg. N-butyl-B-carboline-3-carboxylate (B-CCB) ) FLUMAZENIL > A specific benzodiazepine antagonist > Available only for intravenous administration half-life is 1 hour Duration - 30 to 60 mins. Primary indication: management of benzodiazepine overdose & reversal of its sedative effects Dosage: 1 mg given over 1-3 minutes cummulative dose of 1 to 5 mg given over 2 to 10 mins additional course within 20-30 mins should sedation reappear. May cause seizures ORGAN LEVEL EFFECTS 1. Sedation: defined as a suppression of responsiveness to a constant level of stimulation, with decreased spontaneous activity and ideation 2. Hypnosis: - induction of sleep A. The latency of sleep onset is decreased B. The duration of stage 2 NREM sleep is increased C. The duration of REM sleep is decreased D. The duration of stage 4 NREM slow-wave sleep is decreased 3. Anesthesia > diazepam and midazolam, are used IV but have not proved to be fully successful as agents capable of producing surgical anesthesia 4. Anticonvulsant effects > clonazepam, nitrazepam, lorazepam and diazepam have selective actions that are clinically useful in the management of seizure states > they are capable of inhibiting the development and spread of epileptiform activity in the CNS 5. Muscle relaxation > they exert inhibitory effects on polysynaptic reflexes and internuncial transmission > high doses may also depress transmission at the skeletal neuromuscular junction 6. Respiratory System: - hypnotic dose -* slight depression of alveolar ventilation similar to natural sleep changes dose dependent depression of alveolar ventilation and pO2 -p CO2 narcosis and respiratory acidosis 7. Cardiovascular System - minimal decrease in blood pressure, cardiac output and systemic vascular resistance - increased coronary blood flow decrease both cerebral blood flow and cerebral 02 utilization 8. Gastrointestinal Tract - improve anxiety related GI disorders decrease nocturnal gastric secretion UNTOWARD EFFECTS: tolerance physiologic & psychologic dependence drowsiness impaired judgement diminished motor skills hypersensitivity reactions impairment of sexual function - lightheadedness - ataxia - chest pain - incontinence - nausea - headache - vertigo DRUG INTERACTIONS: - Additive effect - alcohol, opioid analgesics, anticonvulsants, and phenothiazines - Delays hepatic clearance & prolongs elimination half time of diazepam & metabolites - cimetidine - Enhanced CNS depression effects antihistamines, antihypertensives and tricyclic antidepressants Types: A. Long Acting Barbiturates: > Phenobarbital (Luminal sodium) > Barbital (Veronal) > Mephobarbital ( Mebaral) > Metharbital (Gemonil) B. Intermediate Acting Barbiturates: > Amobarbital (Amytal) > Butarbital (Butisol) C. Short Acting Barbiturates: > Pentobarbital (Nembutal sodium) > Secobarbital (Seconal) D. Ultra – Short Acting Barbiturates > Thiopental (Penthotal) > Hexobarbital (Sombulex) > Methohexital ( Brevital ) > Thiamylal (Surital) PHARMACOKINETICS: A. Absorption - rapid & complete absorption after oral intake Distribution - redistribution from brain to highly perfused tissues such as skeletal muscle and subsequently to poorly perfused adipose tissue > crosses the placental barrier - thiobarbiturates very lipid soluble - rapid entry into CNS - readily cross placental barrier - intravenous route -+ for induction of anesthesia & management of status epilepticus - cummulative with repeated administration Biotransformation - complete metabolism or conjugation in the liver Elimination half life : Seco- 18 hrs Pento – 48 hrs Pheno – 4-5 days Excretion - mainly unchanged in the urine elimination rate significantly increased by alkalinization of the urine PHARMACODYNAMICS Barbiturates depress neuronal activity at the midbrain reticular formation, facilitating and prolonging the inhibitory effects of GABA and glycine > Barbiturates increase the duration of GABA-mediated chloride ion channel opening Organ Level Effects: 1. Sedation > Barbiturates have euphoriant effects 2. Hypnosis > Barbiturates alter the stages of sleep in the dose-dependent manner > they decrease sleep latency, decrease number of awakenings and decrease body movements 3. Anesthesia > Thiopental and methohexital are very lipid soluble, penetrating brain tissue rapidly following IV administration > which are therefore useful in anesthesia practice 4. Anticonvulsant Effects: > Phenobarbital and metharbital (converted to phenobarbital in the body) are effective in the treatment of generalized tonic-clonic seizures 5. Respiration: > Depress both respiratory drive & the mechanisms responsible for the rhythmic character of respiration > Diminish neurogenic drive & in higher doses, suppress hypoxic & chemoreceptor drive > Laryngospasm – chief complaint of barbiturate anesthesia 6. Cardiovascular System > Cardiovascular reflexes are obtunded by partial inhibition of ganglionic transmission –slight fall or no change in BP > Decrease in renal plasma flow and in cerebral blood flow with a marked fall in CSF pressure 7. Liver > Combine with cytochrome 450 & competitively interfere with the biotransformation of a number of drugs > Chronic administration causes a marked increase in the protein and lipid content of the hepatic smooth endoplasmic reticulum 8. Kidney > Severe oliguria or anuria in acute barbiturate poisoning, largely as a result of the marked hypotension UNTOWARD EFFECTS: After-effects: - drowsiness for only a few hours - residual CNS depression up to 10-22 hrs. - distortions of mood - impairment of judgement & fine motor skills - other residual effects: vertigo, nausea, vomiting, diarrhea, over excitement - awakes slightly intoxicated, euphoric & energetic irritability and temper Paradoxical Excitement: - common among geriatric & debilitated patients - phenobarbital & N-methylbarbiturates Pain: - prescribed for localized or diffuse myalgic, neuralgic, or arthritic pain - may cause restlessness, excitement & delirium in presence of pain Hypersensitivity: - may occur in patients with asthma, urticaria, angioedema - localized swelling,erythematous dermatitis exfoliative dermatitis -- phenobarbital ABSOLUTE CONTRAINDICATION: ACUTE INTERMITTENT PORPHYRIA – barbiturates enhance porphyrin synthesis DRUG INTERACTIONS A. increased CNS-depressant effects: 1. other CNS depressants (ethanol) 2. isoniazid 3. methylphenidate 4. monoamine oxidase inhibitors B. induction of microsomal hepatic enzymes -> accelerated disappearance of drugs & endogenous substances accelerated metabolism of vitamins D & K hamper bone mineralization & lower Ca`+ absorption (phenobarbital) * coagulation defects in neonates whose mothers are taking phenobarbital > enhance metabolism of steroid hormones -* endocrine disturbances > enhance metabolism of oral contraceptives unwanted pregnancy C. induce hepatic generation of toxic metabolites of chlorocarbon anesthetics & carbon tetrachloride - ~ promote lipid peroxidation - facilitates the periportal necrosis of the liver MISCELLANEOUS HYPNOTIC-SEDATIVE DRUGS: a.Buspirone b.Zolpidem c.Zaleplon d.Carbamates e. Alcohols: i. Paraldehyde ii. Chloral Hydrate iii. Ethchlorvynol i. Meprobamate f. Piperidinediones ii.Ethinamate i. Gluthetimide ii. Methyprylon g. Clomethiazole h. etomidate Buspirone Relieves anxiety without marked sedative or euphoric effects No hypnotic, anticonvulsant or muscle relaxant property Mechanism of action: partial agonist at 5-HT1A receptors less psychomotor impairment than diazepam suitable for generalized anxiety states - > Pharmacokinetics: rapid oral absorption - extensive first-pass metabolism & form active metabolites elimination halflife: 2-4 hrs -> prolong in liver dysfunction -—+ reduced with rifampicin (cytochrome P450 inducer) increased plasma levels with erythromycin & ketoconazole ( inhibitors of CYP3A4) untoward effects: tachycardia, palpitations, nervousness, GIT distress, paresthesias, dose-dependent pupillary constriction BP elevations on patients taking MAO inhibitors Zolpidem An imidazopyridine derivative with hypnotic actions Mechanism of action: binds selectively to BZ, (omega, ) subtype of benzodiazepine receptors and facilitates GABA-mediated neuronal inhibition Actions antagonized by flumazenil Minimal muscle relaxing and anticonvulsant effect Short-term treatment of insomnia Minor effects on sleep patterns but suppress REM sleep at higher doses. Less tolerance & dependence with extended use than with benzodiazepines Pharmacokinetics: rapidly metabolized in the liver to inactive metabolites elimination half-life ---> 1.5 – 3.5 hours Precautions: patients with hepatic dysfunction, elderlies & cimetidine Drug interaction: rifampicin — decreases half-life of zolpidem Ethanol & other CNS depressants — respiratory depression Zaleplon Resembles zolpidem Mechanism of action: binds selectively to BZ, receptor subtype, facilitating inhibitory actions of GABA Decreases sleep latency Little effect on total sleep time or on sleep structure. Pharmacokinetics: rapidly absorbed from GIT rapid onset & short duration of action elimination half-life of about 1 hour. metabolized mainly by hepatic aldehyde oxidase & partly cytochrome P450 > Amnesic effects & next-day psychomotor impairment may occur Alcohols: Paraldehyde Rapid acting hypnotic —> sleep ensues in 10-15 min Rapidly absorbed & widely distributed 70-80% metabolized in the liver > elimination half-life is 4-10 hrs > excreted in expired air & urine untoward effects = acidosis, bleeding gastritis fatty changes in liver & kidney (toxic hepatitis & nephrosis) toxic dose: 25-150 gm Chloral Hydrate Has little analgesic activity Decreases sleep latency, awakenings & slow wave sleep > Metabolized in the liver to trichloroethanol >Excreted mostly in urine as urochoralic acid Untoward effects: Irritating to skin & mucous membrane Unpleasant taste, epigastric distress, nausea, occ. Vomiting CNS: lightheadedness, malaise, ataxia, nightmares "Hangover" idiosyncratic - disoriented, incoherent, paranoid behavior Icterus -acute poisoning Delirium & seizures Ethchlorvynol a hypnotic-sedative with rapid onset & short duration of action > has anti-convulsant & muscle relaxant property acts within 15-30 minutes > distribution half-life is 1-3 hours > elimination half life is 10-25 hrs. untoward effects: mintlike aftertaste dizziness, nausea & vomiting hypotension, facial numbness mild "hangover" hypersensitivity - urticaria, fatal thrombocytopenia, cholestatic jaundice acute intoxication - severe respiratory depression, bradycardia idiosyncratic - mild stimulation to marked excitement & hysteria contraindicated in patients with porphyria > drug interaction: enhance metabolism of oral anticoagulants > toxic dose: 10-25 gram Piperidinediones Gluthetimide Rarely recommended for continued use because of its addiction liability, severity of withdrawal symptoms & certain features of acute intoxication Exhibits pronounced anticholinergic activity > Absorbed from GIT, 50% bound to plasma proteins, 95% metabolized in the liver Half-life is 5-22 hours Untoward effects: "hangover" excitement blurring of vision, gastric irritation, headache, skin rashes thrombocytopenia, aplastic anemia, leukopenia acute intoxication - less severe respiratory depression antimuscarinic actions - xerostomia, ileus, urinary bladder atony, long lasting mydriasis, hyperpyrexia abstinence syndrome - tremulousness, tachycardia, fever, tonic muscle spasms &generalized convulsions > Toxic dose: 10-20 gms Methyprylon, Hypnotic Metabolized in the liver & eliminated almost entirely by urinary excretion Plasma half-life is 4 hrs > Should be avoided in patients with intermittent porphyria Untoward effects: "hangover" nausea, vomiting, diarrhea, esophagitis and headache idiosyncratic excitement acute intoxication - hypotension, shock, pulmonary edema coma - may last up to 5 days Toxic dose: 6 gm Carbamates Meprobamate Introduced as antianxiety agent in 1955 Causes widespread depression of CNS but not anesthesia > Also acts as anticonvulsant > Well absorbed when administered orally Metabolized in the liver & eliminated in the urine Half-life is 6-17 hours Untoward effects: Major - Drowsiness & ataxia Impairment of learning & motor coordination, prolonged reaction time Acute intoxication- severe or fatal respiratory depression, hypotension, shock, heart failure Abrupt discontinuation withdrawal syndrome (anxiety, tremors, insomnia, hallucinations, generalized seizures) Toxic dose: 36 grams Ethinamate is a urethane Rapid onset & short duration of action Inactivated in the liver & excreted as glucoronide in the urine Untoward effects: Nausea, occasional vomiting, rash Idiosyncratic excitement Fever, thrombocytopenia Other Sedative-Hypnotics: Etomidate Used as an intravenous anesthetic Advantages: lacks pulmonary and vascular depressant activity Negative inotropic effect Used as sedative-hypnotics in ICU's, during intermittent positive-pressure breathing and in epidural anesthesia Clomethiazole Has sedative, muscle relaxant and anticonvulsant properties - - Used for hypnosis of elderly & institutionalized patients, for preanesthetic sedation, management of ethanol withdrawal SEDATION DRUG DOSAGE HYPNOSIS DRUG bedtime) DOSAGE (at Alprazolam 0.25-0.5mg 2-3x daily Chloral hydrate 500-1000 mg Buspirone 5-10 mg 2-3x daily Estazolam 0.5-2 mg Chlordiazepoxide 10-20 mg 2-3x/d Flurazepam 15-30 mg Clorazepate Lorazepam 2-4 mg 5-7.5 mg 2x/d Drug Dosage Halazepam Lorazepam 20-40 mg 3-4x/d Drug Dosage(at bedtime Secobarbital 100-200 mg 1-2 mg Temazepam once or twice/d Triazolam 7.5-30 mg Oxazepam 15-30 mg 3-4x/d 0.125-0.5 mg Phenobarbital 15-30 mg Zaleplon 2-3x/d 5-20 mg Prazepam 10-20 mg Zolpidem 2-3x/d 5-10 mg CLINICAL PHARMACOLOGY of SEDATIVE- HYPNOTICS: 1. Treatment of anxiety states Benzodiazepines -* most common anxiolytic drug (generalized anxiety disorder) alprazolam = panic disorders & agoraphobia major depressive disorders Phenobarbital, meprobamate, antihistamines Beta-blockers > clonidine 2.Treatment of sleep disorders Benzodiazepines Zolpidem Zaleplon 3.Preoperative medication 4.anticonvulsant 5.treatment of delirium tremens 6.induction of anesthesia 7. skeletal muscle relaxation in specific N-M disorders meprobamate benzodiazepines 8.diagnostic aid or treatment in psychiatry THANK YOU VERY MUCH AND STUDY WELL! THE ALCOHOLS Ethanol Pharmacokinetics water soluble molecule that is absorbed rapidly from the GIT. After ingestion in the fasting state, peak blood concerntrations are reached within 30 mins Presence of food delay absorption Rapid distribution with tissue levels approximating the concentration in blood. In the CNS, the concentration rises quickly since the brain receives a large proportion of blood flow and ethanol readily crosses biologic membranes Over 90% of alcohol consumed is oxidized in the liver Excreted through the lungs and in the urine Two Major Pathways of Alcohol Metabolism to Acetaldehyde: Alcohol Dehydrogenase Pathway: The primary pathway involves alcohol dehydrogenase (ADH), a cytosolic enzyme that catalyzes the conversion of alcohol to acetaldehyde. Enzyme found in liver, brain and stomach Microsomal Ethanol Oxidizing system (MEOS) also known as the mixed function oxidase system uses NADPH as a cofactor in the metabolism of ethanol chronic alcohol consumption results in significant increases not only in ethanol metabolism but also in the clearance of other drugs eliminated by the MEOS system Acetaldehyde Metabolism * The product of this reaction is acetate which can be further metabolized to CO2 and water. Oxidation is inhibited by disulfiram, a drug that has been used to deter drinking by alcohol dependent patients undergoing treatment When ethanol is consumed in the presence of disulfiram, acetaldehyde accumulates and causes an unpleasant reaction of facial flushing, nausea, vomiting, dizziness, and headache. Other drugs like metronidazole, cefotetan, trimethoprimm inhibit aldehyde dehydrogenase and can cause a disulfiram like reaction if combined with ethanol Some people primarily of Asian descent, have a genetic deficiency in the activity of the mitochondrial form of aldehyde dehydrogenase. Blood Alcohol Concentration (BAC) and clinical effects in nontolerant individuals BAC (mg/dl) Clinical Effect 200-300 Sedation, subjective “high” increased reaction times Impaired motor function, slurred speech, ataxia Emesis, stupor 300-400 Coma >500 Respiratory depression, death 50-100 100-200 PHARMACODYNAMICS OF ACUTE ETHANOL CONSUMPTION: Central Nervous System: causes sedation, relief of anxiety and at higher concentrations slurred speech, ataxia, impaired judgement and disinhibited behavior- drunkenness CNS depressant, at high blood concentrations, it induces coma, respiratory depression and death No specific receptor but has been shown to participate in signaling pathways, including neurotransmitter receptors for amines, amino acids, and opioids; enzymes such as Na+/K+ ATPase, adenylyl cyclase, phosphoinositide specific phospholipase C and ion channels such as those for Ca+ Acute ethanol exposure enhances the action of GABA Also inhibits the ability of glutamate to open the cation channel associated with NMDA subtype of glutamate receptors, which is implicated in many aspects of cognitive function including learning and memory. Heart: >significant depression of myocardial contractility has been observed in individuals who acutely consume moderate amounts of alcohol at blood concentration above 100 mg/dL. Acetaldehyde is implicated as a cause of cardiac dysfunction by altering myocardial stores of catecholamines. Smooth Muscle Ethanol is a vasodilator probably as a result of both CNS effects (depression of the vasomotor center) and direct smooth muscle relaxation caused by acetaldehyde. Severe overdose may cause hypothermia Also relaxes the uterus CONSEQUENCES OF CHRONIC ALCOHOL CONSUMPTION Liver and Gastrointestinal Tract: liver disease is the most common medical complication of alcohol abuse alcoholic fatty liver, a reversible condition may progress to alcoholic hepatitis and finally to cirrhosis and liver failure most common cause of chronic pancreatitis in Western world also alters pancreatic epithelial permeability and promotes the formation of protein plugs and calcium carbonate containing stones malnutrition and vitamin deficiencies due to malabsorption Nervous System Tolerance and physical dependence Alcohol withdrawal – hyperexcitability in mild cases and seizures, toxic psychosis, and delirium tremens in severe ones Psychologic depencence – compulsive desire to experience the rewarding effects of alcohol and for current drinkers, a desire to avoid the negative consequences of withdrawal Up regulation of NMDA subtype of glutamate receptors and voltage sensitive Ca2+ channels may underlie the seizures that accompany the alcohol withdrawal syndrome. GABA neurotransmission –believes to play a central role in tolerance and withdrawal Neurotoxicity generalized symmetric peripheral nerve injury that begins with distal paresthesias of the hands and feet gait disturbances and ataxia due to degenerative changes in the CNS dementia and rarely demyelinating disease. - Wernicke-Korsakoff syndrome – paralysis of the external eye muscles, ataxia and a confused state that can progress to coma and death associated with thiamin deficiency and rarely seen in the absence of alcoholism Most patients are left with a chronic disabling memory disorder known as Korsakoff’s psychosis alcohol may also impair visual acuity, with painless blurring that occurs over several weeks of heavy alcohol consumption Cardiovascular System: dilated cardiomyopathy with ventricular hypertrophy and fibrosis interference of ethanol with the beneficial effects of B blockers and ACE inhibitors heavy drinking, associated with both atrial and ventricular arrhythmias hypertension (more than three drinks per day) A number of observational studies concluded that moderate alcohol consumption actually prevents CHD and even reduces mortality – ethanol’s ability to raise serum levels of HDL cholesterol, the ability to inhibit some of the inflammatory processes that underlie atheroscelrosis and the presence in alcoholic beverages (red wine) of antioxidants and other substances that may protect against atherosclerosis. Blood indirectly affects hematopoiesis through metabolic and nutritional effects ,directly inhibits the proliferation of all cellulalr elements in bone marrow most common is mild anemia resulting from alcohol related folic acid deficiency. Iron Deficiency Anemia may result from gastrointestinal bleeding Endocrine System and Electrolyte balance gynecomastia and testicular atrophy ascites, edema and effusions – decreased protein synthesis and portal hypertension alterations of whole body potassium induced by vomiting and diarrhea severe secondary aldosteronism hypoglycemia – impaired hepatic gluconeogenesis ketosis caused by excessive lipolytic factors Fetal Alcohol syndrome chronic maternal alcohol abuse during pregnancy intrauterine growth retardation microcephaly poor coordination underdevelopment of midfacial region ( appearing as a flattened face minor joint anomalies the fetal liver has little or no alcohol dehydrogenase activity, so the fetus must rely upon maternal and placental enzymes for elimination of alcohol Immune System inhibited in the lungs, enhanced in the liver and pancreas suppression of the function of alveolar macrophages, inhibition of chemotaxis of granulocytes, and reduced number and function of T cells Increased Risk of Cancer risk for cancer of the mouth, pharynx, larynx, esophagus and liver small increase in the risk of breast Ca in women. Alcohol Drug Interactions: chronic ethanol consumption and acetaminophen-induced hepatotoxicity inhibits metabolism of Phenothiazines, tricyclic antidepressants and sedative hypnotic drugs potentiates the effects of vasodilatora and oral hypoglycemic agents enhances the antiplatelet action of aspirin MANAGEMENT OF ACUTE ALCOHOL INTOXICATION: most important goals in the treatment are to prevent severe respiratory depression and aspiration of vomitus treatment of hypoglycemia and ketosis by administration of glucose Thiamine – Wernicke-Korsakoff Syndrome Severe vomiting – large amounts of potassium MANAGEMENT OF ALCOHOL WITHDRAWAL SYNDROME The major objective of drug therapy is prevention of seizures, delirium and arrhythmias Potassium, magnesium and phosphate balance should be restored as rapidly as is consistent with renal function Thiamine therapy initiated Substituting a long acting sedative hypnotic drug for alcohol and then gradually reducing (“tapering”) the dose of the long acting drug (benzodiazepines preferred) PHARMACOTHERAPY OF ALCOHOLISM Disulfiram – tetraethylthiuram an inhibitor of aldehyde dehydrogenase is the drug most commonly used rapidly and completely absorbed from the GIT inhibits the metabolism of phenytoin, oral anticoagulants and isoniazid management should be initiated only when the patient has been free of alcohol for at least 24 hours usual oral dose is 250 mg daily taken at bedtime Naltrexone orally available opioid receptor antagonist that blocks the effects of exogenous and endogenous opioids 50 mgs taken once a day Should be used with caution in alcoholic patients with evidence of mild abnormalities in serum aninotransferase activity Combination with disulfiram should be avoided (hepatotoxins) Topiramate drug used for partial and generalized tonic clonic seizures may be effective in reducing craving in chronic alcoholics OTHER ALCOHOLS: METHANOL (methyl alcohol, wood alcohol) a constituent of many commercial solvents in the home, found in the form of “canned heat” or in windshield washing products can be absorbed through the skin or from the respiratory or GIT and is then distributed in body water. Primary mechanism of elimination of methanol in humans is by oxidation to formaldehyde, formic acid and CO2. Methanol poisoning – visual disturbance described as “like being in a snowstorm.” ETHYLENE GLYCOL used as heat exchangers in antifreeze formulations and as industrial solvents relatively harmless and eliminated by the kidney, it is metabolized to toxic aldehydes and oxalate. Three stages of ethylene glycol overdose Within the first few hours after ingestion – transient excitation followed by CNS depression 4-12 hours – severe metabolic acidosis Finally – delayed renal insufficiency follows deposition of oxalate in renal tubules * Fomepizole * - an alcohol dehydrogenase inhibitor used for the treatment of ethylene glycol poisoning and methanol poisoning THANK YOU VERY MUCH AND STUDY WELL!