Highly selective α1A-adrenergic blocker
ATC code: G04CA04 (Silodosin)
Brand names
Rapaflo
A highly selective α1A-adrenoceptor antagonist on prostate, bladder neck, and proximal urethra. α1A/α1B selectivity is 162:1 – much higher than tamsulosin's 16:1. This reduces hypotension and syncope risk but raises retrograde ejaculation rates (28% with silodosin vs 8% with tamsulosin per Yuan 2013 meta-analysis). Onset 3–4 hours after first dose. CYP3A4- and UGT2B7-metabolized.
First line
First-line for symptomatic benign prostatic hyperplasia with moderate-to-severe symptoms per EAU 2024 alongside tamsulosin and alfuzosin. Dose 8 mg once daily. Effective on IPSS and Qmax. Particularly suitable in patients with orthostatic hypotension risk factors – less BP drop than tamsulosin. Does not reduce prostate size – with a large gland, combine with a 5α-reductase inhibitor (, ).
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Silodosin is a highly selective α1A-adrenergic blocker. It is prescribed for men with benign prostatic hyperplasia (BPH) (AUA 2023, AEMPS Ficha Técnica). Silodosin is prescribed to men for anti-aging improvement of urination outside a BPH indication. No clinical studies of prophylactic use in this setting exist. The drug has pronounced retrograde ejaculation (in 28% of patients – abnormally frequent versus other α1-blockers), orthostatic hypotension, dizziness, and risk of intraoperative cataract surgery complications (intraoperative floppy iris syndrome). If silodosin was prescribed outside confirmed BPH, consider seeking a second opinion.
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Not used in women.
Not used in women.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Silodosin is evaluated for the following indications with varying evidence strength: Benign prostatic hyperplasia (evidence tier A), Anti-aging and longevity (evidence tier F). See the full indication matrix with dosing and citations above on this page.
Common side effects of Silodosin (≥ 1 in 100): Retrograde ejaculation (28%), Dizziness, Nasal congestion, Diarrhea, Orthostatic hypotension (less than tamsulosin). See the Safety section for uncommon and serious reactions.
FDA category B. Not used in women.
Not used in women.
Silodosin is contraindicated in: Silodosin hypersensitivity; Severe renal impairment (eGFR under 30); Severe hepatic impairment; Age under 18; Female sex (not prescribed). Full list in the Safety section.