ABSTRACT
Mephobarbital (MPB) was introduced into therapeutics by Blum in 1932 and retains some currency as an antiepileptic drug. The importance of stereochemical considerations to the clinical pharmacology and pharmacokinetics of MPB is paramount. This was recognized over two decades ago by German workers who published some incisive chemical and pharmacologic studies on MPB and chemically related chiral barbiturates. Single-dose pharmacokinetic studies were performed in six adult males given racemic MPB orally. R-mephobarbital has been shown to be metabolized by the same cytochrome P-450 isoenzyme as S-mephenytoin. MPB therefore also exhibits this same genetic polymorphism, and some 3–5% of Caucasians who lack the relevant cytochrome P-450 are poor metabolizers. In clinical practice the indications for MPB use are virtually identical to those for use of PB. MPB may offer the reputed advantage of being somewhat less sedating in doses which confer equal protection against epileptic seizures.
