Drug Groups

illicit; approved

Description

A carbamate with hypnotic, sedative, and some muscle relaxant properties, although in therapeutic doses reduction of anxiety rather than a direct effect may be responsible for muscle relaxation. Meprobamate has been reported to have anticonvulsant actions against petit mal seizures, but not against grand mal seizures (which may be exacerbated). It is used in the treatment of anxiety disorders, and also for the short-term management of insomnia but has largely been superseded by the benzodiazepines. (From Martindale, The Extra Pharmacopoeia, 30th ed, p603) Meprobamate is a controlled substance in the U.S.

Indication

For the management of anxiety disorders or for the short-term relief of the symptoms of anxiety.

Pharmacology

Meprobamate is an anxiolytic drug. It was the best selling minor tranquilizer for a time but has largely been replaced by benzodiazepines. Meprobamate has most of the pharmacological effects and dangers of the barbiturates (though it was marketed as being safer). However, it is less sedating at effective doses. It is reported to have some anticonvulsant properties against absence seizures, but can exacerbate generalized tonic-clonic seizures. It has also been used as a hypnotic (sleeping pill). However, its is currently only licensed as an anxiolytic and it is a third or fourth-order choice.

Toxicity

Symptoms of overdose include coma, drowsiness, loss of muscle control, severely impaired breathing, shock, sluggishness, and unresponsiveness. Death has been reported with ingestion of as little as 12 g meprobamate and survival with as much as 40 g.

Affected Organisms

Biotransformation

Hepatic.

Absorption

Well absorbed from the gastrointestinal tract.

Half Life

Plasma half-life is about 10 hours.

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