Methylphenobarbital (INN), also known as mephobarbital (USAN, JAN) and mephobarbitone (BAN), marketed under brand names such as Mebaral, Mephyltaletten, Phemiton, and Prominal, is a drug which is a barbiturate derivative and is used primarily as an anticonvulsant,[2] but also as a sedative and anxiolytic.

A new drug application would have needed to have been submitted to gain marketing approval, which would have taken an estimated five years, during which time patients would be required to change their therapies in any case.

The last available tablets bore an expiration date of March 31, 2012, and the drug will no longer be available in the US when supplies are depleted.

[citation needed] The use of antiepileptic drugs including methylphenobarbital during pregnancy may be associated with birth defects.

[4] Symptoms of overdose of mephobarbital include confusion, decrease in or loss of reflexes, somnolence, fever, irritability, hypothermia, poor judgment, shortness of breath or slow/troubled breathing, slow heartbeat, slurred speech, staggering, trouble in sleeping, unusual movements of the eyes, weakness.