VA Class:CN301
Secobarbital is a barbiturate sedative-hypnotic.
Secobarbital sodium is used principally as a hypnotic in the short-term treatment of insomnia for periods up to 2 weeks in duration; barbiturates appear to lose their efficacy for sleep induction and maintenance after this period of time. If retreatment is necessary, it should be undertaken only upon further evaluation of the patient and after drug-free intervals of 1-2 weeks. Alternative nondrug therapies should be attempted for the treatment of chronic insomnia. The drug also is useful preoperatively to relieve anxiety and provide sedation and has been used for routine sedation.
Secobarbital sodium has been administered IV or IM (parenteral preparations of secobarbital sodium are no longer commercially available in the US) to control status epilepticus or acute seizure episodes resulting from meningitis, poisons, eclampsia, alcohol withdrawal, tetanus, or chorea. The drug also has been used parenterally to provide basal hypnosis for general, spinal, or regional anesthesia or to facilitate intubation procedures. Secobarbital sodium has been used rectally to induce anesthesia in children (e.g., prior to ear, nose, or throat procedures). Secobarbital sodium also has been used parenterally to control acute episodes of agitated behavior in psychoses, but has little value in long-term management of psychoses.
Secobarbital sodium may be administered orally. Secobarbital sodium also has been administered parenterally and rectally, but the injection and suppositories of the drug no longer are commercially available in the US.
Dosage of secobarbital sodium must be individualized. Following chronic administration, the drug should be withdrawn slowly to avoid the possibility of precipitating withdrawal symptoms if the patient is physically dependent on the drug.
The oral hypnotic dose of secobarbital sodium for adults is 100 mg administered before bedtime.154 For the treatment of insomnia, the drug should not be administered for periods exceeding 2 weeks. To prevent rebound in rapid eye movement (REM) sleep, withdrawal of a single therapeutic dose over 5 or 6 days has been recommended when barbiturates are discontinued following prolonged use. When the drug is used to provide preoperative sedation, the usual oral dose is 200-300 mg for adults administered 1-2 hours prior to surgery.154 Although secobarbital sodium is not generally used for routine sedation, a sedative dose of 100-300 mg daily has been administered orally in 3 divided doses to adults. Reduced dosage may be necessary in debilitated or geriatric patients and in patients with renal or hepatic impairment.154
The recommended dose of secobarbital sodium for preoperative sedation in children is 2-6 mg/kg (up to a maximum dose of 100 mg) administered orally 1-2 hours before surgery.154 Although secobarbital sodium generally is not used for routine sedation, a sedative dosage of 6 mg/kg daily has been administered orally in 3 divided doses to children.
Secobarbital sodium shares the toxic potentials of the barbiturates, and the usual precautions of barbiturate administration should be observed. (See Cautions in the Barbiturates General Statement 28:24.04.)
Secobarbital sodium shares the actions of the sedative-hypnotic barbiturates.
Approximately 90% of an oral dose of secobarbital is absorbed from the GI tract within 2 hours after ingestion, and peak plasma concentrations are reached within 2-4 hours. Virtually all of the drug is absorbed following rectal administration. Plasma secobarbital concentrations of 1-5 mcg/mL generally produce sedation, and plasma concentrations of 5-15 mcg/mL produce sleep in most patients; however, plasma concentrations of greater than 10 mcg/mL may produce coma. Plasma concentrations in excess of 30 mcg/mL are potentially lethal.
When hypnotic doses of secobarbital are administered orally, the onset of action usually occurs within 15 minutes. Full hypnotic effect of the drug usually occurs 15-30 minutes following oral or rectal administration, 7-10 minutes following IM administration, and 1-3 minutes following IV administration. (Rectal and parenteral preparations of the drug are no longer commercially available in the US.) The duration of the hypnotic effect is 1-4 hours following oral or rectal administration of an average dose of secobarbital and about 15 minutes following IV administration of a 100- to 150-mg dose.
Approximately 30-45% of the drug is bound to plasma proteins.
Secobarbital has an elimination half-life of about 30 hours.
Secobarbital is metabolized by the liver via penultimate oxidation of the 1-methylbutyl substituent to form 5-allyl-5(3'-hydroxy-1'-methylbutyl)barbituric acid (hydroxysecobarbital), the major metabolite. Oxidation of the allyl substituent may also occur to form 5-[2',3'-dihydroxypropyl-5-(1'-methylbutyl)]barbituric acid (secodiol). These inactive metabolites are excreted in urine unchanged or as glucuronide conjugates. Hydroxysecobarbital may also be further oxidized to a ketone or a carboxylic acid. The allyl substituent at C 5 may be removed, and small quantities of the resulting 5-(1'-methylbutyl)barbituric acid metabolite have been found in urine. Approximately 5% of an oral hypnotic dose of secobarbital is excreted in urine unchanged. Increasing urinary flow enhances excretion of secobarbital only slightly, and alkalinization of the urine produces no clinically important increase in excretion of the drug.
Secobarbital is a barbiturate. The pKa of the drug has been variously reported as 7.74-7.9, and the drug is very lipid soluble. Secobarbital sodium occurs as a white, odorless powder with a bitter taste and is hygroscopic. The sodium salt is very soluble in water and soluble in alcohol.
Secobarbital sodium capsules should be stored in tight containers154, 155 at controlled room temperature between 15-30°C.154
Additional Information
For further information on chemistry and stability, pharmacology, pharmacokinetics, uses, cautions, chronic toxicity, acute toxicity, drug interactions, laboratory test interferences, and dosage and administration of secobarbital, see the Barbiturates General Statement 28:24.04.
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.
Parenteral and oral secobarbital sodium preparations are subject to control under the Federal Controlled Substances Act of 1970 as schedule II (C-II) drugs.
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Capsules | 100 mg* | Seconal® Sodium Pulvules® (C-II) |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
AHFS® Drug Information. © Copyright, 1959-2022, Selected Revisions November 13, 2017. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, MD 20814.