Abuse potential

Unlike other carbamates such as meprobamate and its prodrug carisoprodol, methocarbamol has greatly reduced abuse potential. Studies comparing it to the benzodiazepine lorazepam and the antihistamine diphenhydramine, along with placebo, find that methocarbamol produces increased “liking” responses and some sedative-like effects; however, at higher doses dysphoria is reported. It is considered to have an abuse profile similar to, but weaker than, lorazepam.[13]

Metabolism[edit]

Methocarbamol is the carbamate of guaifenesin, but does not produce guaifenesin as a metabolite, because the carbamate bond is not hydrolyzed metabolically; metabolism is by Phase I ring hydroxylation and O-demethylation, followed by Phase II conjugation. All the major metabolites are unhydrolyzed carbamates.[14][15]

Marketing[edit]

Generic Methocarbamol 750mg Oral Tablet.

Methocarbamol without other ingredients is sold under the brand name Robaxin in the U.K., U.S. and Canada; it is marketed as Lumirelax in France, Ortoton in Germany and many other names worldwide.[16] In combination with other active ingredients it is sold under other names: with acetaminophen (Paracetamol), under trade names Robaxacet and Tylenol Body Pain Night; with ibuprofen as Robax Platinum; with acetylsalicylic acid as Robaxisal in the U.S. and Canada.[17][18] However, in Spain the tradename Robaxisal is used for the Paracetamol combination instead of Robaxacet. These combinations are also available from independent manufacturers under generic names.