Generic Medicine Info
Indications and Dosage
Severe intractable insomnia
Adult: 100-200 mg at bedtime. As amobarbital Na: 60-200 mg at bedtime.
Elderly: Reduce dose.

Adult: 65-200 mg via IM inj (should not exceed 5 mL at any single site) or IV inj (should not exceed 50 mg/min) at bedtime. Max: 1,000 mg as a single dose.
Elderly: Reduce dose.

Adult: As amobarbital Na: 30-50 mg via IM inj (should not exceed 5 mL at any single site) or IV inj (should not exceed 50 mg/min) given 2-3 times daily. Max: 1,000 mg as a single dose.
Elderly: Reduce dose.
Child: 6-12 yr 65-500 mg.
Special Patient Group
Debilitated patient: Reduce dose.
Renal Impairment
Reduce dose.
Hepatic Impairment
Reduce dose. Severe: Contraindicated.
May be taken with or without food.
Reconstitute 500 mg sterile powd for inj in 5 mL sterile water for inj to make a 10% IV soln. Reconstitute 500 mg sterile powd for inj in 2.5 mL of sterile water for inj to make 20% IM soln. Rotate vial to dissolve; do not shake.
Incompatible w/ acidic soln. Syringe: Thiamine.
Dyspnoea or airway obstruction, porphyria, sleep apnoea, pre-existing CNS depression or coma. Severe hepatic impairment.
Special Precautions
Patient w/ CV disease, depression or suicidal ideation, history of drug addiction or acute alcoholism. Renal and mild to moderate hepatic impairment. Elderly and debilitated patients, childn. Pregnancy and lactation.
Adverse Reactions
Bradycardia, syncope, hypotension; apnoea, atelectasis (post-op), hypoventilation; agitation, anxiety, ataxia, confusion, CNS depression, dizziness, fever, hallucinations, headache, insomnia, nightmares, nervousness, psychiatric disturbances, somnolence, abnormal thinking; hyperkinesias; nausea, vomiting, constipation; liver damage; megaloblastic anaemia (following chronic phenobarbital use); angioedema, rash; inj site reaction.
Potentially Fatal: Erythema multiforme and exfoliative dermatitis.
IM/IV/Parenteral/PO: D
Patient Counseling Information
May impair mental or physical abilities requiring mental alertness (e.g. driving or operating machinery).
Monitoring Parameters
Monitor vital signs during and after admin.
Symptoms: CNS depression, absent or sluggish reflexes, underventilation, hypotension, hypothermia, pulmonary oedema, haemorrhagic blisters. Management: Secure airway, support ventilation and perfusion. Admin activated charcoal. Perform haemodialysis and haemoperfusion in serious cases.
Drug Interactions
May reduce plasma levels of oral anticoagulants (e.g. warfarin, dicoumarol, acenocoumarol, phenprocoumon), corticosteroids, griseofulvin, doxycycline, Na valproate and valproic acid. Constant monitoring of blood levels when concomitantly used w/ phenytoin. May increase CNS depressant effect w/ antihistamines, sedative/hypnotics, tranquilisers. May prolong the effect w/ MAOIs. May reduce the effect of estradiol, progesterone, estrone and other steroidal hormones.
Food Interaction
May enhance CNS depressant effect of alcohol.
Mechanism of Action: Amobarbital interferes w/ the transmission of impulses from the thalamus to the cortex of the brain which develops an imbalance in central inhibitory and facilitatory mechanisms.
Onset: W/in 5 min (IV).
Absorption: Readily absorbed from the GI tract.
Distribution: Rapidly distributed to all tissues and fluids; crosses the placenta; enters breast milk (small amounts). Plasma protein binding: Approx 60%.
Metabolism: Undergoes hepatic metabolism via penultimate oxidation of the 3-methylbutyl substituent forming a tertiary alcohol, hydroxyamobarbital (inactive metabolite).
Excretion: Via urine (approx 50% as 3'-hydroxyamylobarbital, approx 30% as N-hydroxyamylobarbital, <1% as unchanged drug); faeces (approx 5%). Half-life: Approx 40 min (1st phase); approx 20-25 hr (2nd phase).
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Amobarbital, CID=2164, (accessed on Jan. 20, 2020)

Powd: Store between 15-30°C.
MIMS Class
Anticonvulsants / Hypnotics & Sedatives
Amytal Sodium Injection, Powder, Lyophilized, for Solution (Marathon Pharmaceuticals, LLC). DailyMed. Source: U.S. National Library of Medicine. Accessed 10/11/2014.

Anon. Amobarbital. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. Accessed 10/11/2014.

Buckingham R (ed). Amobarbital. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. Accessed 10/11/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Amobarbital, Amobarbital Sodium. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). Accessed 10/11/2014.

Disclaimer: This information is independently developed by MIMS based on Amobarbital 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 © 2024 MIMS. All rights reserved. Powered by
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