REVERSIBLE INHIBITION OF FERTILITY IN MALE-RATS WITH NIFEDIPINE

Nifedipine, a dihydropyridine calcium channel blocking drug, was inves tigated for its effects on fertility of male rats. The drug was admini stered subcutaneously, on a single day, using different treatment regi mens (0.05 mg kg(-1) once a day, 0.05 mg kg(-1) twice a day 0.1 mg kg( -1) once a day or 0.25 mg kg(-1) once a day). The highest dose of nife dipine inhibited fertility (measured by quantal pregnancy, fertility i ndex and number of uterine implants) on day of administration. Fertili ty was restored by day 3 following treatment. The effective dose did n ot impair libido, ejaculatory competence (in terms of vaginal sperm nu mbers) or post-implantation losses but caused a significant elevation in preimplantation losses. It is concluded that nifedipine inhibited f ertility by reducing fertilising potential of spermatozoa.