Tocainide is a derivative of lidocaine with anti-arrhythmic action and, unlike lidocaine, can be used for oral treatment. Tocainide was alternatively with carbamazepine given to 12 patients with trigeminal neuralgia in a double-blind cross-over study for 2 weeks. The analgesic effect was estimated each day by the patients using a 0-10-point scale summarizing the frequency and severity of the attacks. The similarity in analgesic effect of the two drugs was striking. A possible analgesic mechanism could be that tocainide blocks the sodium channels in the hyperexcitable nerve membranes in the pain-producing foci in trigeminal neuralgia.