Sildenafil citrate (Viagra) impairs fertilization and early embryo development in mice.

OBJECTIVE: To determine the effects of sildenafil citrate, a cyclic monophosphate-specific type 5 phosphodiesterase inhibitor known to affect sperm function, on fertilization and early embryo cleavage. DESIGN: This acute mammal study included male and female mice assigned randomly, the females sacrificed after mating and their oocytes/embryos evaluated at four time periods after treatment. SETTING: Academic research environment. ANIMAL(S): Male and female CBAB(6) mice. INTERVENTION(S): Female mice were injected intraperitoneally with 5 IU gonadotropin (hCG) to stimulate follicular growth and induce ovulation. They were each caged with a male that had been gavaged with sildenafil citrate (0.06 mg/0.05 mL) and allowed to mate. After 12, 36, 60, and 84 h, females were killed, their oviducts were dissected out, and retrieved embryos were assessed for blastomere number and quality. MAIN OUTCOME MEASURE(S): Fertilization rates and numbers of embryos were evaluated after treatment. RESULT(S): Fertilization rates (day 1) were markedly reduced (-33%) in matings where the male had taken sildenafil citrate. Over days 2-4, the numbers of embryos developing in the treated group were significantly fewer than in the control group. There was also a trend for impaired cleavage rates within those embryos, although this did not reach significance. CONCLUSION(S): The impairments to fertility caused by sildenafil citrate have important implications for infertility centers and for couples who are using this drug precoitally while attempting to conceive.

Sildenafil citrate improves sperm motility but causes a premature acrosome reaction in vitro.

OBJECTIVE: To determine whether sildenafil citrate, a cyclic monophosphate-specific type 5 phosphodiesterase inhibitor, influences sperm motility or the acrosome reaction. DESIGN: Laboratory analysis of sperm motility after exposure to sildenafil citrate using computer-assisted semen analysis and acrosome reaction by fluorescein isothiocyanate-labeled peanut agglutinin staining. SETTING: An assisted reproductive technology (ART) unit. PATIENT(S): Fifty-seven male patients. INTERVENTION(S): Sperm were divided into 90% (those with the best fertilizing potential used in assisted conception) and 45% (the poorer population) fractions by density centrifugation and incubated with sildenafil citrate (0.67 muM) at 37 degrees C for up to 180 minutes. MAIN OUTCOME MEASURE(S): Both the number and velocity of progressively motile sperm were significantly increased by sildenafil citrate between 15 and 135 minutes. Furthermore, samples revealed that these effects were consistent in the 90% and 45% populations of sperm. In both populations, sildenafil also caused a significant increase in the proportion of acrosome-reacted sperm-22.1% compared with 11.8% in the control group of the good quality fraction and 16.6% compared with 9.4% in the control group of the poorer quality fraction. CONCLUSION(S): The use of sildenafil citrate may adversely affect male fertility.

The hidden impact of diabetes on male sexual dysfunction and fertility.

Diabetes affects an increasingly large number of young men of reproductive age. Erectile and ejaculatory difficulties arise due to vascular and neuropathic problems. The treatment of these may have effects on fertility potential. Erectile dysfunction can be treated with mechanical devices and intracavernosal injections. Although these have not been shown to affect fertility directly, they may result in poor compliance and hence reduced frequency of ejaculation with subsequent deterioration in sperm quality. Other medical treatments may have a more direct effect. The phosphodiesterase (PDE) inhibitor pentoxifylline has been shown to affect sperm quality and early embryo development. Therefore, Viagra, also a PDE inhibitor, may affect sperm quality. There is conflicting evidence about this in the literature. Ejaculatory difficulties are also more common in diabetics although treatments such as Trucut testicular biopsy and intracytoplasmic sperm injection have improved the outlook for these patients. There is also some evidence that spermatogenesis is affected by diabetes and that patients have a reduced sperm motility and semen volume. Therefore, diabetes has a significant impact on the fertility of men with this disease both directly and indirectly. The extent of iatrogenic influence on the reduced fertility potential of these patients needs to be researched as a matter of urgency.