Pharmacotherapy of trigeminal neuralgia.

The efficacy of the anticonvulsant drug carbamazepine in the management of trigeminal neuralgia is evidenced in several controlled trials, and the numbers needed to treat to obtain one patient with at least 50% pain relief (NNT) is 1.7. Single small trials have shown that baclofen alone provides pain relief (NNT = 1.4) and that lamotrigine has an additional effect in patients with insufficient relief using carbamazepine or phenytoin (NNT = 2.1). Uncontrolled observations and clinical practice indicate that phenytoin, clonazepam, sodium valproate, gabapentin, and lidocaine will also relieve trigeminal neuralgia. In case of lacking effect of a single drug, combination of two or more drugs may be used, but with the exception of the lamotrigine-carbamazepine combination, this is not evidence-based medicine. Acute exacerbation has successfully been treated with intravenous loading with phenytoin or lidocaine, but again these procedures have not been tested in controlled trials. In conclusion, carbamazepine is the mainstay of pharmacotherapy of trigeminal neuralgia, and secondary drug choices are baclofen, lamotrigine, oxcarbazepine, phenytoin, gabapentin, and sodium valproate. Controlled trials testing the effect of some of these drugs, new drugs, and drug combinations are needed.