SECONAL SODIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SECONAL SODIUM (SECONAL SODIUM).
Secobarbital is a barbiturate that acts as a central nervous system depressant. It potentiates GABA-A receptor activity, increasing chloride ion conductance and leading to neuronal hyperpolarization and inhibition.
| Metabolism | Primarily hepatic via CYP2C19, CYP2C9, and CYP3A4; undergoes glucuronidation. Active metabolite: hydroxysecobarbital. |
| Excretion | Primarily renal elimination of inactive metabolites; <5% excreted unchanged in urine. Minimal biliary/fecal excretion. |
| Half-life | Terminal elimination half-life: 15–40 hours (average 30 hours); prolonged in hepatic impairment, elderly, and neonates. |
| Protein binding | Approximately 45–60% bound to albumin. |
| Volume of Distribution | Vd 1.0–1.5 L/kg; distributes widely into tissues including brain, with high lipid solubility. |
| Bioavailability | Oral: approximately 90% (rapidly and completely absorbed; first-pass metabolism minimal). Rectal: approximately 80–100% (variable). |
| Onset of Action | Oral: 30–60 minutes. Rectal: 15–30 minutes. Parenteral (IM/IV): IV immediate (within 1 minute), IM within 10–15 minutes. |
| Duration of Action | Oral: 1–4 hours (hypnotic effect). IV: 15–40 minutes (anesthetic induction). Duration increased with repeated dosing due to accumulation. |
| Molecular Weight | 260.27 |
100-200 mg orally at bedtime for insomnia; 65-130 mg IM or IV for procedural sedation. Usual adult maximum: 500 mg/day.
| Dosage form | INJECTABLE |
| Renal impairment | GFR 10-50 mL/min: administer q12-24h. GFR <10 mL/min: avoid use or reduce dose by 50% and monitor CNS effects. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: contraindicated. |
| Pediatric use | Generally not recommended for children <12 years. For sedation: 3-5 mg/kg orally; maximum 100 mg. For status epilepticus: 15-20 mg/kg IV over 10-15 minutes, monitor respiratory depression. |
| Geriatric use | Reduce initial dose by 50% (e.g., 50-100 mg orally) due to increased sensitivity and risk of falls; avoid prolonged use. Maximum single dose: 200 mg. |
| 1st trimester | Associated with congenital malformations (e.g., oral clefts) when used during first trimester; avoid unless compelling indication. |
| 2nd trimester | May cause fetal dependence and withdrawal; use only if clearly needed. |
| 3rd trimester | Use near term may cause neonatal respiratory depression, hypotonia, and withdrawal symptoms; avoid or use lowest effective dose. |
Clinical note
Comprehensive clinical and safety monograph for SECONAL SODIUM (SECONAL SODIUM).
| Placental transfer | Rapidly crosses the placenta with fetal serum concentrations reaching 50-100% of maternal levels. |
| Breastfeeding | Secobarbital is excreted into breast milk in low concentrations. Prolonged use may cause drowsiness or withdrawal in nursing infants. Consider risk-benefit; monitor infant for sedation. |
■ FDA Black Box Warning
WARNING: Abuse, misuse, and addiction. Secobarbital can cause physical and psychological dependence. Withdrawal can be life-threatening. Concomitant use with opioids or other CNS depressants may result in profound sedation, respiratory depression, coma, or death.
| Serious Effects |
Hypersensitivity to barbituratesPorphyria (variegate or acute intermittent)Severe hepatic impairmentRespiratory depression (severe)
| Precautions | Respiratory depression: use with caution in patients with respiratory compromise. Tolerance and dependence: risk of abuse. Acute withdrawal syndrome: may be fatal. Use in elderly: increased risk of adverse events. Hepatic impairment: dose adjustment may be required. Suicidal ideation: monitor for depression. |
| Food/Dietary | Avoid alcohol. Grapefruit juice may increase barbiturate levels (monitor). No other significant food interactions. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: Associated with increased risk of congenital malformations including cleft lip/palate and cardiac defects. Second and third trimesters: Chronic use may lead to fetal dependence and withdrawal postnatally; risk of neonatal respiratory depression near term. High doses may cause vitamin K deficiency and neonatal hemorrhage. |
| Fetal Monitoring | Maternal: Serum drug levels, liver function, respiratory status, sedation score. Fetal: Ultrasound for growth and anomalies, fetal movement counts, non-stress test, biophysical profile in third trimester. |
| Fertility Effects | May affect female fertility by interfering with ovulation through hypothalamic-pituitary suppression. In males, may decrease sperm motility and count with chronic use. |
| Clinical Pearls | Secobarbital is a short-acting barbiturate with rapid onset; use for short-term insomnia or procedural sedation. Avoid in porphyria. High abuse potential; monitor for respiratory depression, especially in elderly or with alcohol. Taper to prevent withdrawal seizures. |
| Patient Advice | Take exactly as prescribed; do not increase dose or duration. · Avoid alcohol and other CNS depressants. · Do not drive or operate machinery until you know how this drug affects you. · Do not stop suddenly; withdrawal can be severe (seizures). · Store securely away from children. · May cause dependence; use only for short periods. |