Tocainide therapy in muscle cramps and spasms due to neuromuscular disease.

Significant improvement in symptoms of disabling cramps and muscle spasms was obtained in 9 patients with motor neuron diseases, tetany, and myotonic disorders who were treated with tocainide, a lidocaine analog. No significant side effects were observed except for light-headedness and fatigue in 1 patient, who also showed slight prolongation of intraventricular conduction time. Tocainide is useful in treating disabling muscle spasms and cramps associated with conditions characterized by neuromuscular irritability. This effect is probably based on stabilization of the membrane potential at various levels (motor neurons, peripheral nerve, or muscle fiber membrane).