SECONAL SODIUM

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SECONAL SODIUM (SECONAL SODIUM).

How it works

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.

What the body does with it

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.

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SECONAL SODIUM (SECONAL SODIUM).

Breastfeeding	Excreted into breast milk; M/P ratio approximately 0.4. Infant exposure may cause sedation, poor feeding, and respiratory depression. Alternative agents preferred; if used, monitor infant for drowsiness and weight gain.
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.

Warnings & precautions

■ 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.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to barbiturates, history of porphyria, severe respiratory insufficiency, acute or chronic pain (due to paradoxical excitation), history of substance abuse, pregnancy (especially third trimester), breastfeeding.

Clinical Precautions

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.

Clinical Tips & Counseling

Drug interactions

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SECONAL SODIUM

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SECONAL SODIUM (SECONAL SODIUM).

How it works

What the body does with it

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.

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SECONAL SODIUM (SECONAL SODIUM).

Breastfeeding	Excreted into breast milk; M/P ratio approximately 0.4. Infant exposure may cause sedation, poor feeding, and respiratory depression. Alternative agents preferred; if used, monitor infant for drowsiness and weight gain.
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.