How Would You Find Out You’re Sterile If You’re Taking Dutasteride?

Dear Dr. Rassman,

reading your ISHRS-post concerning the korean Avodart study left me a bit confused and raised several questions/remarks: You talked about a colleague of yours reporting two of his patients have become sterile on the drug. Luckily, this sterility turned out to be reversible. First of all, after thinking about this a little while, I wondered how they have even found out to be sterile given that under no circumstances you should have unprotected sex while on dutasteride due to a potential risk of harming unborn life.

Secondly, there is a study discussing the effect of both active ingredients, finasteride and duasteride, on semen paramaters in healthy men. I´m citing from the abstract that can be found on PubMed.org: “In both treatment groups total sperm count was significantly decreased at 26 wk (D, -28.6%; F, -34.3%) but not at 52 wk (D, -24.9%; F, -16.2%) or the 24-wk follow-up (D, -23.3%; F, -6.2%). At 52 wk, semen volume was decreased (D, -29.7%; F, -14.5%, significantly for D) as was sperm concentration (D, -3.2%; F, -7.4%, neither significant).”

The study dates from May 2007 and was conducted by scientist of the University of Washington, Seattle.

Now my question is: Given the results stated above as well as the information you got directly from Merck, posted earlier on this blog, don´t you think the sterility the two men faced was due to the intake of dutasteride IN COMBINATION with some genetic predisposal to fertility problems if the changes in semen parameteres aren´t that dramatical?

And second: Is there any evidence or even theory this sterility could be irreversible?

Many thanks in advance!

I just reported what I was told by my colleague who was concerned about the sperm count of his son, so he did a test to determine what it was after the dutasteride was give for 6 months. He did it with another one of his patients (maybe more, but he only told me of two) and no sperm were seen on the count.

I don’t want to panic people reading this who are on dutasteride, but I might suggest that they check their sperm count maybe once a year or so. If the Korean dutasteride study had included the sperm count, it would’ve saved us the focused concern on sterility as a complication of the drug (temporary or permanent).