Effect of chlorpromazine on skeletogenesis. The result of maternal administration of the drug in experimental rats.

Chlorpromazine hydrochloride (CPZ) is known to induce intrauterine and extrauterine growth retardation. A single dose of CPZ (100 mg/kg) was administered to pregnant CF rats on the 14th day of gestation (sperm positive=day 0). Fetuses were collected from the 16th to the 20th day of gestation and processed for alizarin red-S stain. Ossification was delayed by 1 to 3 days in the long bones of the extremities, by 1 day in the scapulae and by 2 to 3 days in the ilium. Ischium and pubis remained unossified until the 20th day of gestation. Ossification of the skull bones was also delayed as manifested by the presence of wide sutures in the treated cases. The number and range of ossified vertebral bodies and arches in the treated group were always less than those in the control group. The sternebrae were most affected. The ribs also showed a significant delay in maturity.