Effect of single oral doses of various neuroleptic drugs on salivary secretion rate, pH, and buffer capacity in healthy subjects.

The effects of melperone, thioridazine, levomepromazine, and chlorprotixene on salivary secretion rate, pH, and buffer capacity was studied in eight healthy volunteers given single oral doses of placebo or 10, 25, and 50 mg of the drugs in a single-blind crossover design. Both resting and stimulated saliva samples were collected before and every hour for 6h after administration. All drugs reduced secretion rate and lowered pH and buffer capacity, mostly in a dose-dependent manner. The effects of levomepromazine and chlorprotixene were more pronounced than those of melperone and thioridazine.