Inhibition of the action of anticonvulsants by lithium treatment.

The present study demonstrates that the effectiveness of anticonvulsants significantly decreases following lithium treatment (3 doses of 50 mg/kg of LiCl given every 12 hr). The anticonvulsant action of phenytoin, phenobarbital and of 3 carbonic anhydrase inhibitors: methazolamide, acetazolamide, ethoxzolamide, was assessed in rats subjected to maximal electroshock. In a chronic study on tolerance development to the anticonvulsant action of acetazolamide, lithium treatment (10 mg/kg per day) has been shown to inhibit gradually the action of acetazolamide. These results are consistent with the hypothesis that norepinephrine and dopamine are involved in the action of anticonvulsants.