SODIUM BUTABARBITAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SODIUM BUTABARBITAL (SODIUM BUTABARBITAL).
Barbiturate that enhances GABA-A receptor activity, increasing chloride ion conductance and causing CNS depression.
| Metabolism | Primarily hepatic via CYP450 enzymes (e.g., CYP2C9, CYP2C19); glucuronide conjugation. |
| Excretion | Renal excretion of unchanged drug and metabolites; approximately 30-50% as unchanged drug in urine. Minor fecal elimination (<5%). |
| Half-life | Terminal elimination half-life 40-60 hours in adults; prolonged in hepatic impairment and elderly. |
| Protein binding | Approximately 35-50% bound to plasma proteins (albumin). |
| Volume of Distribution | 0.8-1.0 L/kg; indicates extensive distribution into total body water and tissues, including brain. |
| Bioavailability | Oral: 80-95% (well absorbed); not administered via other routes except intravenous. |
| Onset of Action | Oral: 30-60 minutes; Intravenous: within 5 minutes. |
| Duration of Action | Sedation: 4-6 hours; Hypnosis: 6-8 hours. Duration may be prolonged with repeated dosing due to accumulation. |
| Molecular Weight | 237.25 |
50-100 mg orally or intramuscularly 3-4 times daily as a sedative; 100-200 mg orally or intramuscularly for preoperative sedation.
| Dosage form | TABLET |
| Renal impairment | GFR 30-50 mL/min: administer 50% of usual dose every 8-12 hours; GFR 10-29 mL/min: administer 25% of usual dose every 12-16 hours; GFR <10 mL/min: avoid use or administer 12.5% of usual dose every 24 hours. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50% and increase dosing interval to every 8-12 hours; Child-Pugh Class C: contraindicated. |
| Pediatric use | Sedative: 2-6 mg/kg/day orally or intramuscularly divided every 6-8 hours, maximum 100 mg/dose; Preoperative sedation: 1-3 mg/kg intramuscularly 30-90 minutes before procedure, maximum 100 mg/dose. |
| Geriatric use | Initiate at 25-50 mg orally or intramuscularly 2-3 times daily; increase gradually based on response and tolerability; avoid doses >100 mg/day due to increased risk of cognitive impairment and falls. |
| 1st trimester | Avoid; barbiturates cross placenta and may be teratogenic. Risk of congenital malformations, including cleft palate and cardiac defects, especially in first trimester. |
| 2nd trimester | Avoid if possible; can cause fetal dependence and withdrawal. Use only if clear benefit outweighs risk. |
| 3rd trimester | Avoid; associated with neonatal withdrawal syndrome, respiratory depression, and bleeding due to vitamin K deficiency. |
Clinical note
Comprehensive clinical and safety monograph for SODIUM BUTABARBITAL (SODIUM BUTABARBITAL).
| Placental transfer | Crosses placental barrier freely; achieves fetal levels similar to maternal levels due to high lipid solubility. |
| Breastfeeding | Butabarbital is excreted into breast milk in small amounts. It may cause drowsiness, poor feeding, or withdrawal in neonates. Use with caution; alternative agents preferred during lactation. |
■ FDA Black Box Warning
May be habit forming; risks of dependence, withdrawal, and abuse. Use with caution in patients with history of substance abuse.
| Serious Effects |
Known hypersensitivity to barbituratesHistory of porphyria (acute intermittent porphyria, variegate porphyria)Severe respiratory insufficiency (e.g., COPD, sleep apnea)Severe hepatic impairmentMyasthenia gravisAddiction to sedative-hypnotics or history of substance abuse
| Precautions | Respiratory depression (especially with alcohol/other CNS depressants), tolerance, physical dependence, withdrawal syndrome, paradoxical excitation, use in pregnancy (neonatal hemorrhage), pediatric/geriatric sensitivity, hepatic/renal impairment. |
| Food/Dietary | Avoid grapefruit juice as it may increase barbiturate levels. Alcohol should be avoided due to additive CNS depression. High-fat meals may delay absorption; take on empty stomach for faster onset if desired. |
Loading safety data…
| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | First trimester: Crosses placenta; associated with oral clefts (odds ratio 2.0) and neural tube defects. Second and third trimesters: Chronic use may cause fetal dependence and withdrawal; high doses near term may cause respiratory depression in neonate. |
| Fetal Monitoring | Monitor maternal vital signs, sedation level, signs of withdrawal; fetal monitoring (non-stress test/biophysical profile) with chronic use; neonatal monitoring for respiratory depression and withdrawal symptoms postpartum. |
| Fertility Effects | No established effects on fertility; barbiturates may induce hepatic enzymes affecting hormone metabolism; theoretical risk of menstrual irregularities. |
| Clinical Pearls | Sodium butabarbital is a short-acting barbiturate used for sedation and insomnia. Avoid in patients with porphyria. Monitor for respiratory depression, especially with concurrent CNS depressants. Tolerance and dependence develop rapidly; limit use to 2 weeks. Rebound insomnia may occur upon discontinuation. Contraindicated in severe hepatic impairment. |
| Patient Advice | Take exactly as prescribed; do not increase dose or duration. · May cause drowsiness; avoid driving or operating machinery. · Avoid alcohol and other CNS depressants (e.g., opioids, benzodiazepines). · Do not stop abruptly; withdrawal risks including seizures. · May be habit-forming; store securely. · Notify prescriber if pregnant, breastfeeding, or history of depression/suicidal thoughts. |