Nurses Compass
Drug Guide
Pentobarbital
Classification
Therapeutic: Sedative-Hypnotic, Anticonvulsant
Pharmacological: Barbiturate
FDA Approved Indications
- Short-term treatment of insomnia
- Preoperative sedation
- Control of convulsive seizures
Mechanism of Action
Pentobarbital enhances the activity of gamma-aminobutyric acid (GABA) at GABA_A receptors, increasing chloride ion influx and causing hyperpolarization of neurons, leading to sedative, hypnotic, and anticonvulsant effects.
Dosage and Administration
Adult: Dosage varies based on indication; for sedation, typically 160-200 mg at bedtime. For preoperative sedation, 60-100 mg IV or IM or as directed by medical protocol.
Pediatric: Use and dosing must be individualized; start with lower doses, typically 1-3 mg/kg for sedation.
Geriatric: Lower doses are recommended due to increased sensitivity and decreased metabolism.
Renal Impairment: Use with caution; monitor for increased sedative effects.
Hepatic Impairment: Use with caution; metabolism may be decreased, requiring dose adjustments.
Pharmacokinetics
Absorption: Well absorbed after oral and parenteral administration.
Distribution: Widely distributed in body tissues including the brain.
Metabolism: Primarily hepatic metabolism via oxidation to inactive metabolites.
Excretion: Renal excretion of unchanged drug and metabolites.
Half Life: About 15-50 hours in adults; may be prolonged in the elderly and those with hepatic impairment.
Contraindications
- Hypersensitivity to barbiturates or other components.
- Porphyria.
Precautions
- Use with caution in patients with respiratory impairment, liver disease, or a history of substance abuse.
- Risks of dependence, overdose, and respiratory depression. Life-threatening respiratory and cardiovascular depression can occur.
Adverse Reactions - Common
- Drowsiness (Common)
- Dizziness (Common)
- Gastrointestinal upset (Uncommon)
Adverse Reactions - Serious
- Respiratory depression (Serious)
- Hypersensitivity reactions including Stevens-Johnson syndrome (Serious)
- Dependence and withdrawal syndrome (Serious)
Drug-Drug Interactions
- Other CNS depressants (e.g., opioids, benzodiazepines, alcohol) increasing sedative effects and risk of respiratory depression.
- CYP450 enzyme inducers or inhibitors affecting metabolism.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor respiratory and cardiovascular status, level of consciousness, and signs of dependence.
Diagnoses:
- Impaired gas exchange
- Risk for dependence
- Risk for injury related to sedation.
Implementation: Administer as prescribed, monitor vitals and mental status, and educate about dependence and overdose risks.
Evaluation: Assess for therapeutic effect, side effects, and signs of toxicity.
Patient/Family Teaching
- Do not operate machinery or drive until effects are known.
- Avoid alcohol and other CNS depressants.
- Report signs of respiratory depression, excessive sedation, or allergic reactions.
- Do not suddenly stop medication to avoid withdrawal.
Special Considerations
Black Box Warnings:
- Risks of respiratory depression, somnolence, coma, and death when used with other CNS depressants or in overdose.
Genetic Factors: Patients with a history of porphyria should avoid.
Lab Test Interference: May interfere with certain laboratory tests, monitor accordingly.
Overdose Management
Signs/Symptoms: Confusion, ataxia, nystagmus, respiratory depression, coma, hypotension.
Treatment: Supportive care including airway management, monitor vital signs, activated charcoal if within an hour of ingestion, and hemodialysis in severe cases.
Storage and Handling
Storage: Store in a tightly closed container at room temperature away from light and moisture.
Stability: Stable under recommended storage conditions for the duration of the expiration date.