Definite and sustained improvement with pimozide of two patients with severe trigeminal neuralgia. Some neurochemical, neurophysiological and neuroendocrinological findings.

In the present study we report two typical cases of trigeminal neuralgia in whom all conventional drug treatments were attempted without success, and in whom low doses of pimozide, a dopaminergic blocking agent, provoked a definite and sustained improvement. All biological markers used in these cases provided indirect evidence that a central serotonergic hypoactivity is an underlying mechanism in this disease. A low intestinal tone, raised levels of norepinephrine, dopamine, platelet serotonin and non-platelet plasma serotonin were registered during relapses and normalized during improvement periods. Pimozide was not able to improve the depressive state diagnosed in these two cases, nor in 13 other trigeminal neuralgia patients (not reported in this study).