15: Anaesthesia Please select a topic: 15.1 General Anaesthesia 15.2 Local anaesthesia Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 1 of 11 Date: 1.12.2012 15.1 General Anaesthesia Intravenous anaesthetics Thiopental sodium 500mg injection Etomidate Lipro 2mg/ml injection Ketamine 10mg/ml, 50mg/ml and 100mg/ml injection Propofol Lipuro 1% and 2% (2% ITU only) Dose - Propofol injection 1% (10mg/mL): induction of anaesthesia, by intravenous injection or infusion, 1.5-2.5mg/kg (less in those over 55 years). Maintenance of anaesthesia, by intravenous injection 25-50mg repeated according to response, or by intravenous infusion 4-12mg/kg/hour. - Thiopental injection 2.5% (25mg/mL): by intravenous injection, induction of anaesthesia, 4-7mg/kg titrated to response. - Etomidate injection 2mg/mL: by slow intravenous injection, 150300micrograms/kg (elderly, 150-200micrograms/kg). Prescribing notes Propofol is contra-indicated in patients allergic to eggs, nuts or soya, and should be used with caution in patients with epilepsy due to increased risk of convulsions. Propofol is used in sub-anaesthetic doses by infusion for sedation. Propofol is used for total intravenous anaesthesia. Thiopental is used for rapid sequence induction of anaesthesia and may be used in other patients who are allergic to propofol. It is contra-indicated in patients allergic to barbiturates or with porphyria. Whilst thiopental has good anti-epileptic properties, it has a very long halflife and as such its effects can take days to wear off. This may severely delay assessment of neurological status in patients who have received it for prolonged periods for status epilepticus. Ketamine may be useful for sedation or induction of anaesthesia by the intramuscular route as well as IV, and for refractory bronchospasm in ventilated patients. For further information on sedation on Critical Care, see Critical Care Department Sedation Guideline. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 2 of 11 Date: 1.12.2012 Inhalational anaesthetics Desflurane liquid Isoflurane liquid Sevoflurane liquid Dose - Dosage is variable and titrated to individual patient requirement. See BNF. Prescribing notes Isoflurane is less expensive than other agents. Sevoflurane is associated with fewer adverse induction effects and can be used for rapid inhalational induction in place of intravenous agents. When used for maintenance of anaesthesia, sevoflurane is more economical when used with low-flow fresh-gas settings. All volatile anaesthetic agents (e.g. isoflurane, sevoflurane) can trigger malignant hyperthermia; nitrous oxide does not trigger malignant hyperthermia. Adequate scavenging or external venting should be used. Use of absorption breathing systems can permit use of low fresh gas flow techniques which can result in significant economies with these agents. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 3 of 11 Date: 1.12.2012 Antimuscarinic drugs Atropine 1mg/10ml minijet Atropine 600 microgram/ml injection Atropine 3mg/10ml injection pre-filled syringe Atropine 1mg/5ml injection pre-filled syringe Glycopyrronium 200 microgram/ml injection Hyoscine hydrobromide 400 microgram/ml injection Dose - Atropine sulphate injection 600micrograms/mL: by intravenous injection, prophylaxis or treatment of bradycardia, 300-600micrograms. During reversal of neuromuscular blocking agent, 0.6-1.2mg in conjunction with neostigmine. In accordance with UK Resuscitation Council Guidelines, asystolic cardiac arrest, 3mg intravenously as a single dose once only; electromechanical dissociation (EMD) if heart rate less than 60/minute on monitor, 3mg intravenously. - Glycopyrronium bromide injection 200micrograms/mL: by intravenous injection, prophylaxis or treatment of bradycardia, 200-600micrograms. In conjunction with neostigmine, up to 600micrograms. Prescribing notes Atropine and glycopyrronium are both suitable for reducing salivation prior to upper airway endoscopy. Glycopyrronium is first choice in older patients as it causes less tachycardia than atropine. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 4 of 11 Date: 1.12.2012 Sedative and peri-operative drugs Diazepam 5mg/ml injection Midazolam 1mg/ml, 2mg/ml and 5mg/ml injection Lorazepam 1mg tablets Temazepam 10mg and 20mg tablets Temazepam 10mg/5ml oral solution Dose - Diazepam tablets 5mg, 10mg; oral solution 2mg/5mL: 5-10mg 1-2 hours before procedure. - Temazepam tablets 10mg, 20mg; oral solution 10mg/5mL: pre-medication, 10-20mg (elderly, 10mg) 1 hour before operation. - Lorazepam tablets 1mg: 2-3mg the night before operation, or 2-4mg 1-2 hours before operation. - Midazolam injection 2mg/mL: by intravenous injection, 1mg (max 10mg) titrated slowly to response. Prescribing notes Lorazepam may be preferred for pre-operative sedation because of its amnesic effects. Flumazenil can be used to reverse the effect of benzodiazepines. Midazolam is the drug of choice for intravenous sedation but has no analgesic effect. For further information on sedation on Critical Care, see Critical Care Department Sedation Guideline. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 5 of 11 Date: 1.12.2012 Non-opioid analgesics Ketorolac 30mg/ml injection Paracetamol 1g/100ml injection Diclofenac 75mg/ml injection (Dyloject®) – Theatres only Diclofenac suppositories 12.5mg, 25mg , 50mg, and 100mg Opioid analgesics Alfentanil 500 microgram/ml Alfentanil 5mg/ml injection – ITU only Fentanyl 100 microgram/2ml injection and 500 microgram/10ml injection Remifentanil 1mg and 2mg injection Morphine sulphate injection 10mg/mL, 15mg/mL, 20mg/mL, 30mg/mL; intravenous infusion 50mg/50mL Diamorphine injection 5mg, 10mg, 30mg, 100mg, 500mg Prescribing notes Fentanyl, alfentanil, remifentanil, morphine and diamorphine are used during anaesthesia under specialist supervision. Since there is a very wide variation in dose requirements, dose should be adjusted to individual patient needs and indication. Opioid analgesics given in small doses before or with induction reduce the dose requirement of some drugs used during anaesthesia. Alfentanil, fentanyl and remifentanil are useful because of their rapid onset and short duration of action. Naloxone may be used to reverse the effects of opioids. Older patients are particularly susceptible to respiratory depression and constipation secondary to opiates. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 6 of 11 Date: 1.12.2012 Muscle relaxants Atracurium 25mg/2.5ml, 50mg/5ml and 250mg/25ml injection Pancuronium 4mg/2ml injection Rocuronium 50mg/5ml injection Vecuronium 10mg injection Suxamethonium 100mg/2ml injection Dose - Atracurium besilate injection 10mg/mL: by intravenous injection, 20-50mg for intubation followed by 5-10mg increments or infusion at 300-600 micrograms/kg/hour. - Vecuronium bromide injection 10mg vial: by intravenous injection, 3-8mg for intubation followed by 1-2mg increments. - Suxamethonium chloride injection 50mg/mL: by intravenous injection, 1mg/kg (range 0.3-1.1mg/kg); usual range 20-100mg. - Rocuronium bromide injection 10mg/mL: by intravenous injection, 30-80mg. Prescribing notes Repeated suxamethonium doses can cause intense bradycardia or cardiac arrest and patients should be pretreated with an anticholinergic agent. Suxamethonium is a depolarising agent causing rapid paralysis. Prolonged paralysis occurs in 1:2400 patients following administration of suxamethonium, as a genetically transmitted defect of metabolism. Suxamethonium can trigger malignant hyperthermia. Suxamethonium should be used with caution in patients with high potassium levels, such as in renal failure or burns. Vercuronium may be a preferred choice in patients with bronchospasm due to minimal histamine-releasing properties. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 7 of 11 Date: 1.12.2012 Anticholinesterases used in anaesthesia Neostigmine 2.5mg injection Neostigmine 2.5mg plus glycopyrronium 500 microgram injection Prescribing notes Neostigmine is used for the reversal of neuromuscular blocking agents. It requires concurrent antimuscarinic administration to prevent serious bradycardia or cardiac arrest. Other drugs for reversal of neuromuscular blockade Sugammadex 200mg/2ml and 500mg/5ml injection Antagonists for central and respiratory depression Doxapram 100mg/5ml injection Flumazenil 500 microgram/5ml injection Naloxone 2mg/2ml syringe and 400 microgram/ml injection Dose Please note that the use and doses of these agents in anaesthesia are different from those given for the treatment of poisoning/overdose. Chapter 16, Appendix 2. - Naloxone injection 400micrograms/mL: by intravenous injection, initially 100200micrograms (1.5-3micrograms/kg); if response inadequate, increments of 1OOmicrograms every 2 minutes; further doses may be required by intravenous bolus or infusion. Higher doses are required for poisoning. Patients should be observed and monitored until the risk of re-narcosis is over. - Flumazenil injection 1OOmicrograms/mL: by intravenous injection, initially 200micrograms over 15 seconds, then 1OOmicrograms at 60-second intervals if required; usual dose range, 300-600micrograms; max total dose 1mg (2mg in intensive care); question aetiology if no response to repeated doses. By intravenous infusion, if drowsiness recurs after injection, 1OO4OOmicrograms/hour, adjusted according to level of arousal. Prescribing notes The antagonist should be matched to the cause of the respiratory depression. All doses should be titrated to the patient's response. Since the duration of action of naloxone may be less than the duration of the opioid causing respiratory depression, repeat doses may be required. Naloxone also antagonises the analgesic effects of opioids. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 8 of 11 Date: 1.12.2012 Flumazenil is potentially hazardous in patients receiving central nervous system drugs, and may precipitate withdrawal symptoms in patients who are benzodiazepine dependent. Drugs for malignant hyperthermia Dantrolene 20 mg injection Dose - Dantrolene sodium injection 20mg vial: by rapid intravenous injection, 12mg/kg (3-6 x 20mg vials requiring 60mL sterile water per vial). Repeated as required to a cumulative max. of 10mg/kg. Prescribing notes Advice regarding the treatment of hyperthermia induced by drugs other than anaesthetics, such as MDMA or cocaine, can be obtained from the National Poisons Information Service or TOXBASE. Patient must be transferred to intensive care as soon as practicable. Body temperature may be reduced by surface cooling with ice, or administration of cooled intravenous infusions. Treatment of malignant hyperthermia may also include : o sodium bicarbonate o mannitol (may need to melt precipitate first) o furosemide o dextrose/insulin infusion o intravenous beta-blocker Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 9 of 11 Date: 1.12.2012 15.2 Local Anaesthesia Lidocaine 1% injection (10mg/ml) Lidocaine 2% injection (20mg/ml) Lidocaine 1%, 2% with adrenaline 1:200 000 injection Lidocaine 2% with adrenaline 1:80 000 injection Lidocaine 10% spray Lidocaine 5% ointment Lidocaine 4% topical ointment (LMX4®) Lidocaine 0.2% Glucose 5% infusion 500ml Bupivacaine 0.25%, 0.5% injection (10ml) Bupivacaine 5mg in Glucose 80mg/ml injection Bupivacaine 0.125% 250ml infusion Bupivacaine 0.25%, 0.5% with adrenaline 1:200 000 Levo-bupivacaine 0.25% and 0.5% injection Levobupivacaine 0.1% with fentanyl 500mg/250ml infusion Prilocaine 1% injection Prilocaine 20mg/ml Glucose 60mg/ml (Prilotekal 2%) injection Mepivacaine 3% cartridges for dental use Ropivacaine 75mg/10ml & 100mg/10ml injection Prescribing notes Local anaesthetics can be very toxic and therefore great care should be taken to avoid inadvertent injection into a vein or accidental overdose. Vasoconstrictors (adrenaline or octopressin) should not be injected into extremities. Choice of local anaesthetic, concentration and the presence of a vasoconstrictor can depend on total dosage required, site of insertion/application and intended surgical procedure. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 10 of 11 Date: 1.12.2012 Maximum doses of each agent also depend on total dose, site of injection, presence of vasoconstrictor and vascular state of the tissues. Levobupivacaine is less cardiotoxic than bupivacaine and can be used for high dose blocks which have a significant potential for accidental intravenous placement. Lower concentrations of anaesthetics cause less stinging on injection; irritation is reduced by warming anaesthetic solutions prior to injection. The total dose of adrenaline should not exceed 500 microgram (i.e. 0.5ml of a 1 in 1000 solution). Lidocaine has a faster onset of action and less toxic than bupivacaine. However bupivacaine has the advantage of a longer duration of action. Drugs for local anaesthetic toxicity Intralipid 20% injection Dose - Intralipid 20% injection: 1.5ml/kg over 1 minute then infusion of 0.25ml/kg/min. Repeat bolus every 3-5mins up to 3ml/kg total dose. Continue infusion until haemodynamic stability is restored. Increase rate to 0.5ml/kg/min if BP declines. Max total dose of 8ml/kg. Red = Hospital use only Green = GP & Hospital use. Drugs not classified as Red, Amber or Amber 2 are classified as Green by default Amber 1 = Drugs with shared care agreement Amber 2 = Initiated by Hospital specialist only Gateshead Health NHS Foundation Trust Drug Formulary Drug & Therapeutics Committee Page 11 of 11 Date: 1.12.2012