Ejaculatory dysfunction caused by the new alpha1-blocker silodosin: A preliminary study to analyze human ejaculation using color Doppler ultrasonography.
OBJECTIVE
In order to clinically investigate the mechanism of ejaculatory dysfunction attributable to the alpha1-blocker silodosin, a real-time observation of ejaculation by healthy males was performed.


METHODS
Following intake of silodosin, a newly developed selective alpha1-blocker for benign prostatic hypertrophy, ejaculation was dynamically observed using color Doppler ultrasound in three healthy males. Normal ejaculation was also investigated in the same manner.


RESULTS
With silodosin intake, no antegrade ejaculation was observed in cases 1 or 2. In case 1, seminal fluid slowly but continuously flowed out from the seminal vesicles into the bladder. In case 2, only a small amount of seminal fluid flowed into the bladder during the ejaculatory sensation. In case 3, ejection of a small amount of semen from the external urethral orifice was observed and inflow of a small amount of seminal fluid into the bladder was also captured. Without silodosin intake, all three subjects exhibited antegrade ejaculation.


CONCLUSIONS
The mechanism of ejaculatory dysfunction is intricately related to retrograde ejaculation (retrograde inflow of seminal fluid), insufficient contraction of the seminal vesicles, and insufficient rhythmic contraction of the muscles of the pelvic floor.
Nagai
Atsushi
A
Department of Urology, Kawasaki Medical School, Kurashiki, Okayama, Japan. nagai@med.kawasaki-m.ac.jp
Hara
Ryoei
R
Yokoyama
Teruhiko
T
Jo
Yoshimasa
Y
Fujii
Tomohiro
T
Miyaji
Yoshiyuki
Y
D000317:Adrenergic alpha-Antagonists / Q000009:adverse effects*; D000328:Adult; D004542:Ejaculation; D006801:Humans; D007211:Indoles / Q000009:adverse effects*; D008297:Male; D012735:Sexual Dysfunction, Physiological / Q000139:chemically induced* / Q000000981:diagnostic imaging*; D018615:Ultrasonography, Doppler, Color; D055815:Young Adult
D000317:Adrenergic alpha-Antagonists; D007211:Indoles; C095285:silodosin