Pentobarbital

Intramuscular
Hypnotic

Intravenous
Hypnotic

Oral
Hypnotic

Oral
Sedation

Rectal
Sedation

Rectal
Hypnotic

Dosage adjustment needed.

Dosage adjustment needed.

Bronchopneumonia, severe pulmonary impairment. History of porphyria and addiction to sedative and hypnotics. Concomitant Na oxybate.

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.

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

May impair ability to perform activities requiring mental alertness or physical coordination (e.g. driving and operating machinery).

Monitor blood count, renal and hepatic function prior to and periodically during long-term therapy. Monitor BP.

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.

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.

Increased CNS depression w/ alcohol.

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.

Tab/Inj:
Store between 15-30°C.
Supp:
Store between 2-8°C.

Hypnotics & Sedatives

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.