From the Guidelines
Flomax (tamsulosin) commonly causes retrograde ejaculation as its main ejaculatory dysfunction side effect. This occurs when semen flows backward into the bladder instead of forward through the urethra during ejaculation, resulting in reduced or no semen during orgasm (dry orgasm). Tamsulosin works by relaxing smooth muscles in the prostate and bladder neck to improve urine flow in men with benign prostatic hyperplasia (BPH), but this same mechanism affects the bladder neck during ejaculation. The medication's alpha-1 adrenergic receptor blocking action particularly targets the alpha-1A receptors that control the bladder neck's closure during ejaculation. According to the aua guideline on management of benign prostatic hyperplasia 1, the use of tamsulosin has been extensively investigated for the treatment of LUTS, and its adverse event profile appears slightly different from other alpha-blocking agents, with a higher probability of ejaculatory dysfunction. Some key points to consider about tamsulosin and ejaculatory dysfunction include:
- The medication's mechanism of action, which relaxes smooth muscles in the prostate and bladder neck, can affect the bladder neck's closure during ejaculation, leading to retrograde ejaculation.
- Studies indicate retrograde ejaculation occurs in approximately 8-18% of men taking tamsulosin, making it more likely to cause this side effect than other alpha blockers, as noted in the guideline 1.
- This side effect is typically reversible when the medication is discontinued, though it may take time to resolve completely.
From the FDA Drug Label
Abnormal Ejaculation Abnormal ejaculation includes ejaculation failure, ejaculation disorder, retrograde ejaculation, and ejaculation decrease. As shown in Table 1, abnormal ejaculation was associated with Tamsulosin Hydrochloride Capsules administration and was dose-related in the U. S. studies.
The type of ejaculatory dysfunction that Flomax (tamsulosin) causes includes ejaculation failure, ejaculation disorder, retrograde ejaculation, and ejaculation decrease 2.
From the Research
Ejaculatory Dysfunction Caused by Flomax (Tamsulosin)
- The type of ejaculatory dysfunction caused by Flomax (tamsulosin) is primarily anejaculation or reduced ejaculation, rather than retrograde ejaculation 3, 4, 5.
- Studies have shown that tamsulosin can decrease ejaculate volume and cause anejaculation in a significant percentage of patients, with one study reporting a 35% incidence of no ejaculation 4.
- The exact mechanism of tamsulosin-induced ejaculatory dysfunction is not fully understood, but it is thought to be related to the drug's effect on the alpha1-adrenoceptors in the vas deferens and seminal vesicles 4, 5.
- Tamsulosin has also been shown to have a negative effect on sperm parameters, including decreased sperm concentration, motility, and morphology 6.
- The incidence of ejaculatory dysfunction with tamsulosin is higher compared to other alpha1-adrenoceptor antagonists, such as alfuzosin 3, 4.