Effects of the calcium antagonists verapamil and nitrendipine on carbamazepine withdrawal

This study was aimed at examining the effects of two frequently used Ca2+ a ntagonists, nitrendipine and verapamil, oil withdrawal after cessation of l ong-term treatment with the anticonvulsant drug carbamazepine in rats. The 48-h interruption of long-term (21 days) carbamazepine treatment led to the appearance of withdrawal characterized by increases bl seizure intensity, the percentage of rats rats with tonic seizures and mortality. Oral treatme nt with the two calcium antagonists in combination with carbamazepine aboli shed the signs of carbamazepine withdrawal. Seizure intensity, the percenta ge of rats rats with tonic seizures and mortality in the groups treated wit h lire combinations of carbamazepine + verapamil and carbamazepine + nitren dipine were significantly lower than those of the group of rats treated wit h carbamazepine alone. In conclusion, some Ca2+ antagonists could attenuate the manifestations of anticonvulsant withdrawal and thus could be used ns adjuvants in long-term anticonvulsant therapy. (C) 1999 Prous Science. All rights reserved.