Silodosin

How it works

It selectively blocks alpha-1A adrenoceptors in the prostate, bladder neck and urethra, relaxing smooth muscle and reducing bladder outflow obstruction and associated voiding symptoms.

Prescribing in practice

• It commonly causes abnormal or retrograde ejaculation, and patients should be advised of this before starting treatment.
• It is associated with intraoperative floppy iris syndrome, so any planned cataract or glaucoma surgery should be flagged to the ophthalmologist before commencing.
• Caution is needed in renal or hepatic impairment and with concomitant potent CYP3A4 inhibitors or other antihypertensives because of the risk of hypotension.

Monitoring

Monitor symptom response and blood pressure, particularly for postural hypotension on initiation and dose changes.

Counselling the patient

• Reduced or absent semen on ejaculation is expected and not harmful.
• Tell your eye surgeon you take this medicine before any cataract operation.
• Stand up slowly, especially when first starting, to avoid dizziness.

Evidence & guidelines

Alpha-blockers are recommended by NICE for moderate to severe lower urinary tract symptoms in benign prostatic hyperplasia; see the SPC for product-specific cautions.