A comparative electrophysiologic study of diazepam and tetrazepam in patients with spasticity

In 14 patients with spasticity efficacy and tolerance of 10 mg diazepam and 50 mg tetrazepam have been compared in a double-blind double-dummy cross-over study. To assess efficacy, the changes in four electrophysiologic tests have been used: Hmax/Mmax ratio, Tmax/Mmax ratio, vibratory inhibition of K reflex, and conditioned amplitudes of Sol H reflex at 70 and 200 ms after stimulation of the tibial nerve at the ankle. Tolerance was evaluated by the induced somnolence (intensity x duration). Electrophysiologic test results were moderately modified in the same direction after both drugs. For the Hmax/Mmax, Tmax/Mmax ratio, and conditioned values, the differences between diazepam and tetrazepam were not significant. For vibratory inhibition, changes induced by tetrazepam were more intense and of longer duration than after diazepam (p = 0.07), indicating that tetrazepam is more potent for reinforcing presynaptic inhibition. Tolerance, as assessed by intensity and duration of somnolence, was significantly better for tetrazepam. The efficacy and tolerance of tetrazepam suggest that it is a more useful agent for the treatment of spasticity than diazepam.