Methohexital


Concise Prescribing Info
Indications/Uses
Anesth.
Dosage/Direction for Use
Adult : IV Induction: 50-120 mg given at a rate of 1 mL/5 sec. Usual adult dose: 1-1.5 mg/kg. Maintenance: 20-40 mg via inj every 4-7 minutes or via continuous infusion using a 0.2% solution at a rate of 3 mL/min.
Dosage Details
Intramuscular
Induction of anaesthesia
Child: >1 month As a 1% solution: 25mg/kg.

Intravenous
Anaesthesia
Adult: Induction: 50-120 mg given at a rate of 1 mL/5 sec. Usual adult dose: 1-1.5 mg/kg. Maintenance: 20-40 mg via inj every 4-7 minutes or via continuous infusion using a 0.2% solution at a rate of 3 mL/min.

Rectal
Induction of anaesthesia
Child: >1 mth: 25 mg/kg as a 1% solution.
Reconstitution
Intramuscular:
Reconstitute preferably with sterile water for inj; 5% dextrose inj or 0.9% sodium chloride inj may also be used.
Intravenous:
Reconstitute with sterile water for inj; 5% dextrose inj or 0.9% sodium chloride inj.
Rectal:
Reconstitute preferably with sterile water for inj; 5% dextrose inj or 0.9% sodium chloride inj may also be used.
Incompatibility
Intravenous:
Methohexital should not be mixed with acid solutions, such as atropine sulfate, metocurine iodide, and succinylcholine chloride for IV admin. Lowered pH may cause free barbituric acid to be precipitated.
Contraindications
Porphyria.
Special Precautions
History of epilepsy. Hepatic impairment. Drowsiness may impair ability to drive and operate machinery; debilitated patients; respiratory, circulatory, renal and endocrine dysfunction; patients with asthma; obstructive pulmonary disease; severe HTN or hypotension; myocardial disease; congestive heart failure; severe anaemia; extreme obesity, elderly, pregnancy and lactation.
Adverse Reactions
Cardiorespiratory depression, tachycardia, hypotension, myocardial depression, bronchospasm, hiccups, laryngeal spasm, hypersensitivity reactions, inj-site reactions, skeletal muscle hyperactivity, convulsions, nausea, abdominal pain, abnormal liver function tests.
Overdosage
Pulmonary oedema, circulatory collapse with loss of peripheral vascular tone, and cardiac arrest may occur. Establish an airway and ensure ventilation and oxygenation. Treat symptomatically and monitor closely.
Drug Interactions
Additive effect with other CNS depressants, alcohol and propylene glycol. Enhances hypotensive effects of ACE inhibitors, antipsychotics, β-blockers, MAOIs. Chronic use of barbiturates or phenytoin appears to reduce methohexital efficacy.
Action
Description: Methohexital is a very short-acting barbiturate anaesthetic. It is at least twice as potent as thiamylal and thiopental with a duration of action only around half as long.
Onset: 30 sec (IV), 2-10 min (IM), or 5-11 min (rectal).
Pharmacokinetics:
Distribution: Widely distributed in all tissues and fluids. Protein binding around 73%. Methohexital crosses the placenta and is found in breast milk.
Metabolism: Rapidly metabolised in the liver by demethylation and oxidation.
Excretion: Excretion mainly via the kidneys.
Storage
Store at 20-25°C.
Disclaimer: This information is independently developed by MIMS based on Methohexital from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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