Carbamazepine inhibits spontaneous activity in experimental neuromas.

In eight adult Sprague-Dawley rats the effect of parenteral carbamazepine on spontaneous discharges from saphenous neuromas (7-42 days following nerve section) was tested. Intravenous carbamazepine produced immediate inhibition of spontaneous activity originating in both A-alpha/beta and A-delta fibers at doses of 2.51-11.2 (7.9 +/- 3.3) mg/kg. In four additional animals, serum levels of carbamazepine were determined following iv administration of the drug. These results indicated that ectopic spontaneous impulse generation from experimental neuromas was inhibited by carbamazepine in the range of serum concentration in which the agent is used to treat trigeminal neuralgia and other painful neuropathies in humans. This implies that the effectiveness of this agent in the treatment of these disorders may result from suppression of peripherally originating ectopic spontaneous activity.