Asterixis associated with carbamazepine.

Some antiepileptic drugs, when administered at toxic plasma levels or more rarely at levels within the therapeutic range, induce asterixis. We report the case of a patient with painful syndrome of central origin being treated with carbamazepine, in which asterixis appeared with toxic serum levels. A pharmacologic interference was also observed between carbamazepine and beta-methyldigoxin, which in our patient was being used to treat disease. The blood digoxin levels were inversely proportional to those of carbamazepine. The therapeutic effectiveness of digoxin being sharply reduced when carbamazepine reached toxic levels.