Potent therapeutic effect of carbamazepine-10,11-epoxide in trigeminal neuralgia
T. Tomson and L. Bertilsson
The clinical effects of carbamazepine-10,11-epoxide were assessed in six
patients with trigeminal neuralgia. The patients were first given an
optimal therapeutic dose of carbamazepine. Part of or the entire
carbamazepine dose was then exchanged for the metabolite
carbamazepine-10,11-epoxide for three to six days. The patients were
unaware of changes in the therapeutic regimen (single-blind). Carbamazepine
dosages ranged from 400 to 1,400 mg/day and carbamazepine-10,11-epoxide
dosages ranged from 300 to 1,000 mg/day. The clinical effects were assessed
by the patients' recordings of pain attacks. When
carbamazepine-10,11-epoxide and carbamazepine were given in similar doses,
the pain control was comparable. On a plasma concentration basis,
carbamazepine-10,11-epoxide had a considerably higher pain-relieving
potency than carbamazepine. During carbamazepine treatment, the epoxide
metabolite contributes to the antineuralgic effect to an extent that might
be comparable to that of the parent drug. No side effects were seen during
carbamazepine-10,11-epoxide therapy.
