Effects of chlorpromazine and other drugs acting on the central nervous system on human sperm motility.

The in vitro effects of chlorpromazine, diazepam, phenytoin and phenobarbitone on human sperm motility were investigated. Only chlorpromazine inhibits human sperm motility and the concentration which decreases sperm motility to 50% of control is 0.22 mM. Caffeine can shift the dose-response curve of chlorpromazine-inhibited sperm motility to right. We support the hypothesis that chlorpromazine acts on the cellular membrane but consider the inhibition of sperm motility an unlikely cause of decreased fertility in chlorpromazine treated patients.