Inhibition of Seminal emission is the main cause of anejaculation induced by a new highly selective alpha1A-blocker in normal volunteers.
BACKGROUND
Recent studies have highlighted the influence of alpha1-adrenoceptor antagonists on ejaculatory function.


OBJECTIVE
We evaluated the effect of a new, highly selective alpha1A-blocker, silodosin, on ejaculatory function of normal volunteers.


METHODS
The study included 15 healthy male urologists who voluntarily participated in the study. They took 4 mg of silodosin or a placebo twice daily for 3 days in a randomized, double-blind crossover design.


METHODS
We investigated the ejaculatory volume, sperm count in urine after ejaculation, and fructose concentration in seminal plasma before and after administration of the agents.


RESULTS
All volunteers on silodosin had a complete lack of ejaculation. Three days after completion of silodosin, the mean ejaculatory volume recovered to the baseline level. There was no sperm in urine after ejaculation under silodosin administration in any volunteer.


CONCLUSIONS
All volunteers on silodosin had anejaculation and did not show post-ejaculate sperm in their urine. The mechanism of ejaculatory dysfunction caused by silodosin is a loss of seminal emission.
Kobayashi
Ko
K
Sapporo Medical University School of Medicine, Sapporo, Japan. kou@sapmed.ac.jp
Masumori
Naoya
N
Hisasue
Shin-ichi
S
Kato
Ryuichi
R
Hashimoto
Kohei
K
Itoh
Naoki
N
Tsukamoto
Taiji
T
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004542:Ejaculation / Q000187:drug effects*; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D012661:Semen / Q000187:drug effects*; D012669:Seminal Vesicles / Q000187:drug effects; D013076:Sperm Count
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D007211:Indoles; C095285:silodosin