Influence of aminophylline and 8-(p-sulfophenyl)theophylline on the anticonvulsive action of diphenylhydantoin, phenobarbital, and valproate against maximal electroshock-induced convulsions in mice.

Aminophylline (theophylline2.ethylenediamine) in the dose of 12.5 mg/kg (i.p.) was ineffective upon all antiepileptic drugs studied and at the higher dose of 25 mg/kg, impaired the anticonvulsant action of phenobarbital and valproate against maximal electroshock in mice. The protection offered by diphenylhydantoin was diminished by aminophylline at 50 mg/kg (0.238 mmol of anhydrous theophylline/kg). In contrast, 8-(p-sulfophenyl)theophylline (a theophylline derivative unable to cross the blood-brain barrier) in the dose of 80 mg/kg (0.238 mmol/kg) did not influence the protective activity of diphenylhydantoin, phenobarbital, and valproate. It might be concluded that the aminophylline-induced impairment of the anticonvulsant action of common antiepileptic drugs results from the central effects of this methylxanthine.