Isoniazid and Other Drugs
1 Division of Clinical Neuropharmacology, Division of Child Neurology, Department of Neurology and Neurosurgery, (Neurology), and Pharmacology, Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St Louis, MO 63110
We read with interest the paper by Block on carbamazepine-isoniazid interaction.1 Although this report mentions that isoniazid has been previously shown to interfere with phenytoin metabolism,2 it fails to mention the interaction between isoniazid and primidone. Sutton and Kupferberg3 have described a patient in whom the addition of isoniazid prolonged the half-life of primidone (Mysoline) and decreased its biotransformation to phenobarbital and phenylethylmalonamide (PEMA). In 1964, Kato et a14 had already demonstrated the inhibitory effect of isoniazid on the metabolism of certain barbiturates in vitro.




