NEMBUTAL SODIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NEMBUTAL SODIUM (NEMBUTAL SODIUM).
Barbiturate that enhances GABA-A receptor activity, prolonging chloride channel opening and increasing neuronal inhibition. Depresses the reticular activating system at higher doses.
| Metabolism | Hepatic via CYP2C9 and CYP2C19; undergoes glucuronidation and oxidation to inactive metabolites; enterohepatic recirculation occurs. |
| Excretion | Renal: ~25% unchanged; hepatic metabolism to inactive metabolites; ~50% excreted as metabolites in urine; biliary/fecal: minor. |
| Half-life | Terminal elimination half-life: 15-40 hours in adults; clinically relevant for accumulation with repeated dosing, especially in hepatic impairment. |
| Protein binding | 70-80% bound to albumin and beta globulins. |
| Volume of Distribution | Vd: 0.8-0.9 L/kg; reflects extensive tissue distribution, particularly into fat. |
| Bioavailability | Oral: ~70-90% (variable due to first-pass metabolism); IM: near 100%. |
| Onset of Action | IV: 30-60 seconds (anesthesia); IM: 10-15 minutes (sedation); Oral: 15-30 minutes (sedation). |
| Duration of Action | IV: 5-15 minutes (anesthesia); IM: 1-2 hours (sedation); Oral: 3-6 hours (sedation). Clinical note: Duration depends on redistribution and dose; prolonged in liver disease. |
| Molecular Weight | 248.28 |
30 mg IV or IM every 6 to 8 hours as needed for sedation; 65 to 100 mg IV or IM for hypnosis; 200 to 500 mg IV or IM for anticonvulsant effect in status epilepticus. Maximum single dose 500 mg.
| Dosage form | CAPSULE |
| Renal impairment | GFR 10-50 mL/min: Administer every 12-24 hours. GFR <10 mL/min: Administer every 24-48 hours or avoid use due to prolonged half-life. |
| Liver impairment | Child-Pugh Class A: Reduce dose by 25%. Child-Pugh Class B: Reduce dose by 50%. Child-Pugh Class C: Avoid use or reduce dose by 75% with close monitoring. |
| Pediatric use | Neonates: 2-6 mg/kg IV/IM for sedation; Infants and Children: 1-3 mg/kg IV/IM for sedation, up to 5 mg/kg for anticonvulsant; maximum single dose 150 mg. |
| Geriatric use | Initiate with 15-30 mg IV or IM; reduce dose by 50% due to increased sensitivity and decreased clearance; avoid in patients with impaired renal or hepatic function. |
| 1st trimester | Avoid use; risk of congenital malformations (cleft palate) and neonatal withdrawal. Use only if clearly needed. |
| 2nd trimester | Use with caution; may cause maternal dependence and neonatal withdrawal. Avoid prolonged use. |
| 3rd trimester | Avoid near term; risk of neonatal respiratory depression, hypotonia, and withdrawal syndrome. |
Clinical note
Comprehensive clinical and safety monograph for NEMBUTAL SODIUM (NEMBUTAL SODIUM).
| Placental transfer | Rapidly crosses placenta; achieves fetal concentrations similar to maternal levels. |
| Breastfeeding | Excreted into breast milk; may cause infant sedation and withdrawal. Use only if benefits outweigh risks; monitor infant for drowsiness and poor feeding. |
| Lactation Rating |
■ FDA Black Box Warning
May be habit-forming; risk of tolerance, physical and psychological dependence. Abrupt discontinuation may precipitate severe withdrawal reactions including seizures and death. Administer only under strict medical supervision.
| Serious Effects |
Hypersensitivity to barbituratesPorphyria (variegate or acute intermittent)Severe respiratory insufficiencySevere hepatic impairment
| Precautions | Respiratory depression, hypotension, and laryngospasm especially with rapid IV administration. Use caution in hepatic/renal impairment, porphyria, or history of substance abuse. Avoid intra-arterial injection (risk of necrosis). |
| Food/Dietary | Avoid alcohol and excessive caffeine. Grapefruit juice may alter metabolism; limit intake. High-fat meals can delay absorption if taken orally. |
Loading safety data…
| L4 (Possibly Hazardous) |
| Teratogenic Risk | Nembutal Sodium (pentobarbital) is classified as FDA Pregnancy Category D. First trimester: Associated with increased risk of congenital malformations, particularly oral clefts, cardiovascular defects, and neural tube defects. Second and third trimesters: Chronic use can lead to fetal dependence and withdrawal syndrome; acute administration near term may cause neonatal respiratory depression, hypotonia, and hypothermia. Risk of hemorrhagic disease of the newborn due to vitamin K deficiency. |
| Fetal Monitoring | Maternal: Monitor vital signs (heart rate, blood pressure, respiratory rate), level of sedation, and signs of respiratory depression. Fetal: Non-stress test and biophysical profile for chronic use; continuous fetal heart rate monitoring during labor if used near delivery. Neonatal: Assess for withdrawal symptoms (irritability, tremors, hypertonia, seizures) and respiratory depression for 24–48 hours after delivery. |
| Fertility Effects | Pentobarbital may interfere with hormonal contraception by inducing hepatic CYP3A4, reducing efficacy of oral contraceptives. In males, high doses can cause testicular atrophy and impaired spermatogenesis in animal studies; human data limited. In females, chronic use may disrupt menstrual cyclicity and ovulation. Reversibility upon discontinuation is presumed. |
| Clinical Pearls | NEMBUTAL SODIUM (pentobarbital sodium) is a short-acting barbiturate used for induction of coma in refractory intracranial hypertension and for sedation in procedures. Monitor for respiratory depression and hypotension, especially during bolus administration. Tolerance develops with repeated use; abrupt cessation may cause withdrawal. Contraindicated in porphyria. Use with caution in hepatic impairment. |
| Patient Advice | This medication causes drowsiness and may impair your ability to drive or operate machinery. · Do not consume alcohol or other central nervous system depressants while taking this medication. · Take exactly as prescribed; do not increase dose or frequency without consulting your doctor. · Do not stop taking this medication suddenly, as withdrawal symptoms may occur. · Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. · Report any difficulty breathing, severe dizziness, or unusual swelling to your healthcare provider immediately. |