Meprobamate Stats & Data
Pharmacology
DrugBankDescription
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is used in the treatment of anxiety disorders, and also for the short-term management of insomnia but has largely been superseded by the benzodiazepines.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.
Mechanism of Action
Meprobamate's mechanism of action is not fully understood; in animal studies, meprobamate is reported to act at multiple sites in the central nervous system, such as the thalamus and limbic system. It binds to the GABAA receptors, leading to inhibitory effects on the neurons transmitting signals in the reticular formation and spinal cord. Consequently, effects such as sedation and altered perception of pain are observed.
Pharmacodynamics
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 It was the best selling minor tranquilizer for a time but has largely been replaced by benzodiazepines.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) but it is less sedating at effective doses. Meprobamate exhibits some anticonvulsant effects in absence seizures; however, it is reported to potentially 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.
Metabolism
Meprobamate undergoes hepatic metabolism.
Absorption
Well absorbed from the gastrointestinal tract.
Toxicity
Symptoms of overdose include coma, drowsiness, loss of muscle control, severely impaired breathing, shock, sluggishness, and unresponsiveness. There have been a case of death resulting from oral ingestion of 12 g of meprobamate. One case study reports the consumption of 40 g of meprobamate resulting in successful survival.
Indication
For the management of anxiety disorders or for the short-term relief of the symptoms of anxiety.