Pentobarbital


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Hypnotic 100-200 mg at bedtime. Sedation 20-40 mg 2-4 times daily. IV Hypnotic Initial: 100 mg, then increase to 200-500 mg. IM Hypnotic 150-200 mg. Rectal Hypnotic 120-200 mg.
Dosage Details
Intramuscular
Hypnotic
Adult: 150-200 mg.
Child: 2-6 mg/kg. Max: 100 mg.
Elderly: Dosage adjustment needed.

Intravenous
Hypnotic
Adult: Initial: 100 mg, then increase to 200-500 mg.
Elderly: Dosage adjustment needed.

Oral
Hypnotic
Adult: 100-200 mg at bedtime.
Elderly: Dosage adjustment needed.

Oral
Sedation
Adult: 20-40 mg 2-4 times daily.
Child: 2-6 mg/kg daily in 3 divided doses. Max: 100 mg.
Elderly: Dosage adjustment needed.

Rectal
Sedation
Child: 2-6 mg/kg daily in 3 divided doses. Max: 100 mg.
Elderly: Dosage adjustment needed.

Rectal
Hypnotic
Adult: 120-200 mg.
Child: 2 mth-1yr 30 mg; 2-4 yr 30 or 60 mg; 5-12 yr 60 mg; 12-14 yr 60 or 120 mg.
Elderly: Dosage adjustment needed.
Renal Impairment
Dosage adjustment needed.
Hepatic Impairment
Dosage adjustment needed.
Contraindications
Bronchopneumonia, severe pulmonary impairment. History of porphyria and addiction to sedative and hypnotics. Concomitant Na oxybate.
Special Precautions
Mentally depressed; acute and chronic pain; hepatic and renal impairment. Parenteral admin to patients w/ HTN, hypotension, CV or pulmonary disease. Too rapid IV admin may result in resp depression, apnoea, laryngospasm, or vasodilation w/ fall in BP. Pregnancy and lactation. Elderly.
Adverse Reactions
Drowsiness, somnolence, dizziness, anxiety, insomnia; hypotension, apnoea, resp depression, bronchospasm, laryngospasm, bradycardia, CNS depression, physical and psychological dependence, psychiatric disturbance, confusion, hallucinations, nightmares, thinking abnormality, syncope, hyperkinesias, ataxia, agitation, nervousness, nausea, vomiting, constipation, pain at inj site.
Potentially Fatal: Stevens-Johnson syndrome.
IM/IV/Parenteral/PO/Rectal: D
Patient Counseling Information
May impair ability to perform activities requiring mental alertness or physical coordination (e.g. driving and operating machinery).
MonitoringParameters
Monitor blood count, renal and hepatic function prior to and periodically during long-term therapy. Monitor BP.
Overdosage
Symptoms: Acute: Unsteady gait, slurred speech, and sustained nystagmus. Chronic: Confusion, poor judgment, irritability, insomnia, and somatic complaints. Management: Treatment is supportive and it is important to maintain adequate airway w/ respiration and oxygen admin if necessary.
Drug Interactions
Additive effect w/ other CNS depressants. Increased plasma concentrations w/ MAO inhibitors. May decrease serum levels of phenytoin, carbamazepine, valproic acid. May increase metabolism of anticoagulants, corticosteroids, griseofulvin, doxycycline and hormonal contraceptives.
Potentially Fatal: Increased sleep duration and CNS depression w/ Na oxybate.
Food Interaction
Increased CNS depression w/ alcohol.
Action
Description: Pentobarbital is a barbiturate mainly used as a sedative and hypnotic. It has been suggested that its pharmacologic effect is due to its property to enhance the activity of GABA by altering GABA receptor-mediated inhibitory synaptic transmissions.
Onset: Oral/Rectal: 15-60 min; IV: 1 min; IM: 10-25 min.
Duration: Oral/Rectal: 1-4 hr; IV: Approx 15 min.
Pharmacokinetics:
Absorption: Well absorbed in the GI tract. Time to peak plasma concentration: 30-60 min.
Distribution: Plasma protein binding: Approx 60-70%.
Metabolism: Hepatic metabolism mainly by hydroxylation to inactive metabolite.
Excretion: Via urine as hydroxypentobarbital. Plasma half-life: 1st phase: Approx 4 hr; 2nd phase: 35-50 hr.
Storage
Tab/Inj:
Store between 15-30°C.
Supp:
Store between 2-8°C.
References
Buckingham R (ed). Pentobarbital. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 17/07/2013.

McEvoy GK, Snow EK, Miller J et al (eds). Barbiturates. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 17/07/2013.

McEvoy GK, Snow EK, Miller J et al (eds). Pentobarbital, Pentobarbital Sodium. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 17/07/2013.

Wickersham RM. Pentobarbital Sodium. Facts and Comparisons [online]. St. Louis, MO. Wolters Kluwer Clinical Drug Information, Inc. https://www.wolterskluwercdi.com/facts-comparisons-online/. Accessed 17/07/2013.

Disclaimer: This information is independently developed by MIMS based on Pentobarbital 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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