Drug does not impair sperm count and other semen characteristics.


WASHINGTON, D.C.— Long-term use of vardenafil (Levitra) at the maximum recommended dosage does not adversely affect sperm concentration, total sperm count per ejaculate, or sperm morphology or motility, a study recently found.

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The study, which is the first to look at the effect of long-term use of vardenafil on semen characteristics, found no changes even after six months, said lead investigator Keith Jarvi, MD, professor of surgery at the University of Toronto.


Because recent data suggest that many men in their reproductive years now use phosphodiesterase-5 (PDE-5) inhibitors for erectile dysfunction (ED), Dr. Jarvi and his colleagues examined the long-term effects of these agents on sperm concentration and other semen characteristics. They compared the effects of vardenafil (20 mg), sildenafil (Viagra, at 100 mg), and placebo in 200 men aged 25-64 years (mean age 39 years). Some men did not have ED; the others had ED but were able to produce semen samples without ED therapy.


Following an unmedicated screening period of four weeks, each subject underwent daily treatment with vardenafil, sildenafil, or placebo for six months. After the treatment phase, men with abnormal semen analyses also participated in a three-month follow-up. The primary variable was the proportion of subjects treated with vardenafil who had a 50% or greater reduction in mean sperm concentration from baseline to six-month last observation carried forward (LOCF), compared with placebo-treated men.


The investigators found that the difference (vardenafil minus placebo) in the proportion of subjects with a 50% or greater decrease in mean sperm concentration from baseline to six-month LOCF was -0.007%. In addition, the outcomes were similar for both sildenafil and vardenafil.

An analysis of the mean changes from baseline to six-month LOCF revealed that sperm concentration was 2 million/mL for vardenafil, 8 million/mL for sildenafil, and 1 million/mL for placebo. The percentage change of normal sperm morphology was -1% for vardenafil, -1% for sildenafil, and 0% for placebo. The change in total sperm motility was similar for vardenafil, sildenafil, and placebo. The researchers observed no statistically significant difference in the median changes in total sperm count per ejaculate (millions) for men taking vardenafil, sildenafil, or placebo.


Dr. Jarvi, who presented findings here at the annual meeting of the American Society for Reproductive Medicine, called this reassuring. He told Renal & Urology News that there appears to be a class effect with PDE-5-inhibitors. “We also looked at sildenafil and we found it had no effect [on fertility parameters]. Tadalafil (Cialis) is the other drug in this class, and a previous study similarly showed no effect,” Dr. Jarvi said.