The effect of oral verapamil on the visual evoked potentials in multiple sclerosis patients.

Abstract

Ionic channel rearrangements through demyelinated axons or supporting media play a significant role in remission of neurological deficits in multiple sclerosis (MS) patients. The role of calcium channel blockers on the MS demyelination sequels is controversial. We studied the change of visual evoked potential (VEP) P100 induced by verapamil in MS patients. We conducted a randomized double blind, placebo controlled, clinical trial on two groups of 20 clinically definite MS patients who had no relapse during the previous one year. Changes in P100 latency were compared between subjects taking 3 dosages of oral verapamil 40 mg, every 8 hours and subjects taking placebo. In the verapamil group, the P100 latencies shortened an average of 6.1 +/- 4 ms compare to placebo group 1 +/- 0.5 ms (P<0.05). Verapamil had no significant effect on the VEP duration. The present study suggests pharmacological manipulation of calcium-dependent process, possibly at the level of demyelinated axon, can rapidly facilitate conduction of electrical impulses in visual pathways of stable MS patients.