Jr. Andrade et al., In vitro effects of sildenafil and phentolamine, drugs used for erectile dysfunction, on human sperm motility, AM J OBST G, 182(5), 2000, pp. 1093-1095
OBJECTIVE: The aim of this study was to determine the effects of sildenafil
and phentolamine on sperm motility in vitro.
STUDY DESIGN: Semen or washed sperm was mixed with Various doses of sildena
fil or phentolamine and analyzed for motility during a 30-minute period. Th
e pH was measured for each of the samples tested, Statistical analyses were
performed with analysis of variance.
RESULTS: A 200-mu g/mL dose of sildenafil had no effect on sperm motility.
However, the highest dose (2000 mu g/mL) significantly reduced motility by
about 50%. The pH was reduced in this high-dose sample. The lowest dose of
phentolamine (20 mu g/mL) had no effect, whereas a dose of 200 mu g/mL resu
lted in a significant reduction in sperm motility. The highest dose (2000 m
u g/mL) stopped virtually all sperm from moving.
CONCLUSION: This study demonstrated a direct dose-related effect of phentol
amine on reducing sperm motility. Only the highest dose of sildenafil had a
n effect, which may have been caused by a decline in pH.