Trade name Rapaflo
Oral medication for the symptomatic treatment of benign prostatic hyperplasia.
Bioavailability of 32% and protein binding of 97%.
Metabolism is by glucuronidation and minor CYP3A4 activity.
Excretion by renal and fecal routes.
Acts as an α1-adrenoceptor antagonist with high uroselectivity.
Causes practically no orthostatic hypotension in contrast to other α1 blockers
Because of high urologic selectivity, causes more problems with ejaculation than other such agents.
May ease the passage of distal ureteral stones
Silodosin may aid the passage of a unilateral distal ureteral stone 4 to 10 mm in diameter (Sur RL et al).
The rate of stone passage was about 23% higher with silodosin compared with placebo.
An 8 mg daily dose for up to 4 weeks of treatment.
Results with silodosin were similar for men and women.
The distal ureter contains the highest concentration of alpha-1 adrenergic receptors and silodosin is an alpha-blocker.
Bockage of the alpha-adrenergic receptors relaxes the ureter and potentially providing a spasmolytic effect,
But silodosin performed no better than placebo at eliminating ureteral stones generally, including medial and proximal stones.
Silodosin had no significant advantages in patient use of pain relievers, emergency room visits, or hospital admissions.
Adverse effects, which included retrograde ejaculation, nausea, dizziness, headache, and nasal congestion.