Modulation of the protective efficacy of common antiepileptic drugs by xanthine derivatives: implications for the clinical use of xanthines in epileptic patients.

Aminophylline and caffeine (methylxanthines) in non-convulsive doses considerably reduced the protective efficacy of common antiepileptic drugs against maximal electroshock-induced convulsions. On the other hand, a new xanthine derivative, enprofylline (3-propylxanthine) which is devoid of convulsive potential and is four to five times more potent as a bronchodilator than aminophylline, remained without influence upon the protection offered by a variety of antiepileptics against electroconvulsions. Similar results were obtained when diprophylline and pentoxifylline were used. The only difference was in the case of pentoxifylline which moderately diminished the protective activity of diphenylhydantoin. It is suggested that the clinical use of aminophylline in epileptic patients for pulmonary reasons should be limited or even stopped. Furthermore, enprofylline, diprophylline and to the lesser degree pentoxifylline seem to possess no dangerous potential to epileptic patients on anticonvulsive therapy.