Meprobamate

Meprobamate (marketed under the brand names Miltown® by Wallace Laboratories, Equanil® by Wyeth, and Meprospan®) is a carbamate derivative which is used as an anxiolytic drug. It was the best-selling minor tranquilizer for a time, but has largely been replaced by the benzodiazepines.

History
Meprobamate was first synthesized by Bernie Ludwig at Carter Products in May 1950. Wallace Laboratories bought the license and named it Miltown after the village Milltown in New Jersey. Launched in 1955, it rapidly became a best seller and famous in the popular media as "Happy Pills." This continued throughout the 1960s but by 1970 it was listed as a controlled substance after it was discovered to cause physical and psychological dependence.

Pharmacology
Although it was marketed as being safer, meprobamate has most of the pharmacological effects and dangers of the barbiturates (though 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.

Meprobamate's mechanism of action is not known. It has been shown in animal studies to have effects at multiple sites in the central nervous system, including the thalamus and limbic system. Meprobamate binds to GABA A receptors which interrupt neuronal communication in the reticular formation and spinal cord, causing sedation and altered perception of pain.

Related drugs include carisoprodol (a prodrug of meprobamate) and tybamate.

Indications
Meprobamate is used for treatment of anxiety disorders or for short-term relief of anxiety.

It has also been used off-label as a sedative. However, it is currently only licensed as an anxiolytic, and is not used as often as the benzodiazepines for this purpose.

Meprobamate is available in 200mg and 400mg tablets for oral administration. Meprobamate is also a component of the combination drug Equagesic (discontinued in the UK in 2002) acting as a muscle relaxant.

Overdose
Symptoms of meprobamate 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 12g of meprobamate and survival with as much as 40g.

Legal Issues
Meprobamate is a Schedule IV drug under the Convention on Psychotropic Substances. Meprobamate may cause GI concretions in overdose, therefore charcoal should be considered even after 4 hours or if levels are rising.

Trivia
Meprobamate was the first drug ever used to lower High Blood Pressure or Hypertension, however it was later replaced by better drugs like Metoprolol which does not make the patient sleepy.