BRAND NAMES
 MECHANISM OF ACTION
Silodosin exerts a selective postsynaptic action, inhibiting the binding of norepinephrine to the α1 receptors.
Three α1 receptor subtypes have been identified, α1a, α1b and α1d:
- α1a and α1d subtypes are predominant in the prostate, bladder, and detrusor muscle.
- α1b subtypes are largely located on vascular smooth muscle.
Silodosin is selective for the α1a subtype; blockade of α1a can lead to smooth muscle relaxation in the lower urinary tract resulting in improved urinary flow rates.
- Treatment of the signs and symptoms of benign prostatic hyperplasia (hesitation before urine flow starts, intermittency, dribbling, weak urinary stream, incomplete emptying of the bladder, nocturia, daytime frequency, urgency and burning).
- Adults and elderly patients: The recommended dose is 8 mg daily, with a meal, preferably at the same time every day.
- Patients with moderate renal impairment: dose should be reduced to 4 mg once daily.
 DOSAGE FORMS AND STRENGTHS
Capsules: 8 mg and 4 mg
- Hypersensitivity to Silodosin
- Severe renal impairment (CCr < 30 mL/min)
- Severe hepatic impairment (Child-Pugh score > 10)
- Concomitant administration with strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir)
 WARNINGS AND PRECAUTIONS
- Postural hypotension and dizziness may develop when beginning Silodosin treatment
- Patients should be screened for the presence of prostate cancer prior to treatment and at regular intervals afterwards because prostate cancer causes many of the symptoms associated with BPH and the two disorders frequently co-exist.
- Concomitant administration of Silodosin with a PDE5 inhibitor (Viagra, Levitra, Cialis, Stendra) can result in additive blood pressure lowering effects and symptomatic hypotension.
- Concomitant administration with strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, itraconazole and ritonavir) is contraindicated because they may cause plasma concentrations of silodosin to increase.
 PREGNANCY AND LACTATION
- Pregnancy Category B (US). Silodosin is not indicated for use in women.
 SIDE EFFECTS
Most common adverse reactions are :
- Ejaculatory disorders such as retrograde ejaculation and anejaculation (ejaculatory volume reduced or absent). This may temporarily affect male fertility but it is reversible within a few days upon discontinuation of treatment
- Orthostatic hypotension
- Nasal congestion
 RELATED LINKS
|Benign Prostatic Hypertrophy|
|5α reductase inhibitors||Dutasteride (Avodart) • Finasteride (Proscar)|
|Alpha 1 antagonists||Alfuzosin (Uroxatral, Xatral) • Doxazosin (Cardura) • Prazosin • Silodosin (Silodyx, Rapaflo) • Tamsulosin (Omnic, Flomax, Secotex) • Terazosin (Hytrin)|
|Phytotherapy||Pygeum africanum • Serenoa repens|
|PDE5 inhibitors||Tadalafil (Cialis)|
|Combination products||Dutasteride/Tamsulosin (Combodart, Jalyn, Duodart)|