Carisoprodol has a unique mechanism of action, qualitatively different from that of meprobamate (Miltown). The muscle relaxant carisoprodol has anxiolytic effects by metabolizing to meprobamate. Some of its effects are believed to occur following being converted into meprobamate. Its mechanism of action is probably similar to meprobamate. Carisoprodol (as with its metabolite meprobamate) is particularly dangerous in combination with alcohol. It was revealed that the sale of meprobamate earned $40,000,000 for the defendants. Related drugs include carisoprodol and tybamate (prodrugs of meprobamate), felbamate, mebutamate, and methocarbamol. A University of Michigan study found that meprobamate affected driving skills. Meprobamate and other muscle-relaxing drugs often were subjects of misuse in the 1950s and 60s. Meprobamate is available in 200- and 400-mg tablets for oral administration. Meprobamate, like barbiturates, possesses an analgesic/anesthetic potential. Meprobamate was found to help in the treatment of alcoholics by 1956. By 1957, meprobamate had become the fastest-growing drug in history. Meprobamate has the ability to activate currents even in the absence of GABA. Specifically, meprobamate is more toxic than benzodiazepines, which are also useful as a muscle relaxant.