Phenobarbital
| Drug monograph · NCLEX study reference | |
| Therapeutic class | Anticonvulsant, sedative |
|---|---|
| Pharmacologic class | Barbiturate (controlled C-IV) |
| Onset / peak / duration | Long acting. |
| Half-life / level | Half-life 53 to 118 hours; therapeutic level 15 to 40 mcg/mL. |
| Routes | PO (oral), IV |
| High-alert (ISMP) | No |
| Black box warning | None |
| Antidote / reversal | Supportive care; no specific reversal. |
| Pregnancy / lactation | Use only if essential. |
Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.
Phenobarbital — Anticonvulsant, sedative; Barbiturate (controlled C-IV).
Identification
- Therapeutic class: Anticonvulsant, sedative.
- Pharmacologic class: Barbiturate (controlled C-IV).
Pharmacology
- Mechanism of action: Enhances GABA activity to raise the seizure threshold.
- Onset / peak / duration: Long acting.
- Half-life / therapeutic level: Half-life 53 to 118 hours; therapeutic level 15 to 40 mcg/mL.
Clinical use
- Indications: Seizures (including neonatal and status), sedation.
- Usual dose, route, frequency: PO or IV, dosed by level.
- Maximum dose / adjustments: Slow IV administration; reduce in hepatic and renal impairment.
Safety
- Contraindications: Porphyria, severe respiratory disease, prior dependence.
- Black box warning: None.
- Interactions: Strong CYP inducer (lowers many drugs), CNS depressants and alcohol (respiratory depression), warfarin, oral contraceptives.
- Pregnancy / lactation: Use only if essential.
- High-alert: No.
Adverse effects
- Common side effects: Sedation, dizziness, cognitive slowing.
- Serious effects to report: Respiratory depression, dependence, severe rash.
- Antidote / reversal: Supportive care; no specific reversal.
Nursing process
- Assessment before administration: Respiratory status, level, seizure baseline.
- Interventions during therapy: Slow IV; monitor respirations; taper to stop.
- Monitor: Drug level, respiratory status, seizure frequency.
- Evaluation / expected outcome: Seizure control.
Patient teaching
- Patient teaching: Avoid alcohol; do not stop abruptly; backup contraception.
- Notify provider if: Slowed breathing, rash, excessive drowsiness.
- Administration tips: Slow IV; consistent dosing.