Chronic treatment with finasteride daily does not affect spermatogenesis or semen production in young men.
OBJECTIVE
Finasteride, an oral type 2, 5alpha-reductase inhibitor, is used in 1 mg. daily doses for the treatment of male pattern hair loss. A dose of 5 mg. finasteride daily reduces ejaculate volume by approximately 25%, and reduces prostate volume by approximately 20% and serum prostate specific antigen (PSA) by approximately 50% in men with benign prostatic hyperplasia. To our knowledge no data exist on the effect of 1 mg. finasteride daily on ejaculate volume or other semen parameters, or on the prostate in young men. Therefore, we studied the potential effect and reversibility of effect of 1 mg. finasteride daily on spermatogenesis, semen production, the prostate and serum PSA in young men.


METHODS
In this double-blind, placebo controlled multicenter study 181 men 19 to 41 years old were randomized to receive 1 mg. finasteride or placebo for 48 weeks followed by a 60-week off-drug period. Of the 181 men 79 were included in a subset for the collection and analysis of sequential semen samples.


RESULTS
There were no significant effects of 1 mg. finasteride on sperm concentration, total sperm per ejaculate, sperm motility or morphology. Ejaculate volume in subjects on finasteride decreased 0.3 ml. (-11%) compared to a decrease of 0.2 ml. (-8%) for placebo, with a median between treatment group difference of -0.03 ml. (1%, 90% confidence interval -10.4 to 13.1, p = 0.915). There were significant but small decreases in prostate volume (-2.6%) and serum PSA (-0.2 ng./ml.) in the finasteride group, which reversed on discontinuation of the drug.


CONCLUSIONS
Treatment with 1 mg. finasteride daily for 48 weeks did not affect spermatogenesis or semen production in young men. The effects of 1 mg. finasteride daily on prostate volume and serum PSA in young men without benign prostatic hyperplasia were small and reversible on discontinuation of the drug.
Overstreet
J W
JW
Department of Obstetrics and Gynecology, University of California, Davis, USA.
Fuh
V L
VL
Gould
J
J
Howards
S S
SS
Lieber
M M
MM
Hellstrom
W
W
Shapiro
S
S
Carroll
P
P
Corfman
R S
RS
Petrou
S
S
Lewis
R
R
Toth
P
P
Shown
T
T
Roy
J
J
Jarow
J P
JP
Bonilla
J
J
Jacobsen
C A
CA
Wang
D Z
DZ
Kaufman
K D
KD
D000328:Adult; D000367:Age Factors; D000505:Alopecia / Q000188:drug therapy; D004334:Drug Administration Schedule; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D018120:Finasteride / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D012661:Semen / Q000187:drug effects*; D013091:Spermatogenesis / Q000187:drug effects*; D013997:Time Factors
D004791:Enzyme Inhibitors; D018120:Finasteride