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NERVOUS SYSTEM › PSYCHOLEPTICS › HYPNOTICS AND SEDATIVES › Barbiturates, plain
pentobarbital
N05CA01
Forms & Strengths
- Injection: 50 mg/mL (20 mL vials)
Adult Dosing
- Sedation: 30 mg to 100 mg IM or IV
- Preoperative sedation: 200 mg IM 1 to 2 hours before surgery
- Insomnia: 100 mg orally or IM at bedtime
- Status epilepticus / Barbiturate coma: Loading dose 5 to 15 mg/kg IV over 1 to 2 hours, followed by continuous infusion of 0.5 to 3 mg/kg/hour titrated to EEG burst suppression
Pediatric Dosing
- Sedation: 2 to 6 mg/kg/day divided, max 100 mg/dose
- Preoperative sedation: 2 to 6 mg/kg IM, max 100 mg
- Status epilepticus: Loading dose 5 to 15 mg/kg IV over 1 to 2 hours, followed by continuous infusion titrated to effect
Indications
- Short-term treatment of insomnia
- Preanesthetic sedation
- Control of acute convulsive episodes (e.g., status epilepticus)
- Reduction of intracranial pressure in neurosurgery or head trauma
Mechanism of Action
- Acts as a non-selective CNS depressant
- Binds to GABA-A receptor complexes, enhancing GABA-mediated chloride ion conductance
- Prolongs the opening duration of chloride channels, hyperpolarizing the neuronal membrane
- Decreases the upward conduction of impulses to the reticular formation
Contraindications
- Hypersensitivity to barbiturates
- History of manifest or latent porphyria
- Severe respiratory depression
- Severe hepatic impairment
- Nephrosis
Adverse Reactions
- Respiratory depression and apnea
- CNS depression, somnolence, hangover effect, and confusion
- Hypotension and bradycardia (especially with rapid IV administration)
- Injection site reactions, thrombophlebitis, and pain
- Tolerance, physical dependence, and withdrawal syndrome
Drug Interactions
- Strong CYP450 enzyme inducer (decreases efficacy of oral contraceptives, anticoagulants, and corticosteroids)
- Additive CNS depression with alcohol, opioids, benzodiazepines, and other sedatives
- May decrease serum concentrations of doxycycline, beta-blockers, and metronidazole
- Valproic acid inhibits barbiturate metabolism, increasing toxicity risk
Curated Content: Needs Vetting Before Put to Clinical Use