Can terazosin (alpha-1 adrenergic blocker) be used to treat overactive bladder?

Terazosin for Overactive Bladder

No, terazosin should not be used as monotherapy for overactive bladder (OAB)—it is an alpha-1 blocker indicated for benign prostatic hyperplasia (BPH) and works by relaxing prostatic smooth muscle, not by addressing the detrusor overactivity that characterizes OAB. 1

Mechanism and Indication Mismatch

• Terazosin blocks alpha-1 adrenoceptors in the prostate, prostatic capsule, and bladder neck, reducing bladder outlet obstruction in men with BPH 1, 2
• The drug has relatively few alpha-1 receptors in the bladder body itself, meaning it does not affect bladder contractility or the involuntary detrusor contractions that define OAB 1
• OAB requires antimuscarinic agents (like tolterodine, solifenacin, oxybutynin) or beta-3 agonists (mirabegron) that directly target detrusor overactivity 3

When Terazosin May Be Appropriate in the Context of Storage Symptoms

Terazosin can be used in combination with antimuscarinics when men have both BPH with bladder outlet obstruction AND overactive bladder symptoms (urgency, frequency, nocturia). 3

Combination Therapy Evidence:

• The 2023 European Association of Urology guidelines support combining alpha-blockers with antimuscarinics in men with both voiding (obstructive) and storage (OAB) symptoms 3
• Terazosin combined with tolterodine showed efficacy and safety in a prospective study of men with LUTS associated with BPH 3
• Meta-analysis confirms efficacy and safety of alpha-blocker plus anticholinergic combinations in BPH patients with LUTS 3

The Clinical Algorithm:

1. If the patient is a man with BPH causing outlet obstruction PLUS OAB symptoms: Consider terazosin (or another alpha-blocker) combined with an antimuscarinic 3
2. If the patient has isolated OAB without outlet obstruction: Use antimuscarinics or mirabegron as first-line, NOT terazosin 3
3. If the patient is a woman with OAB: Terazosin has no role; use standard OAB medications 3

Critical Pitfalls to Avoid

• Do not prescribe terazosin for pure OAB symptoms (urgency, frequency, urgency incontinence) without documented bladder outlet obstruction 1
• Monitor for orthostatic hypotension, dizziness, and asthenia, which are the most common adverse effects of terazosin 4, 2, 5
• Warn patients undergoing cataract surgery about intraoperative floppy iris syndrome (IFIS) associated with all alpha-blockers 4
• In hypertensive men, do not assume terazosin adequately treats hypertension—separate antihypertensive therapy may be needed 6

Dosing Considerations When Used Appropriately

• Start at 1 mg daily and titrate upward to minimize first-dose hypotension 1, 7
• Efficacy is dose-dependent; clinical data support titration up to 10 mg daily 4, 7
• Therapeutic effects on BPH symptoms begin within 2 weeks and are sustained long-term 2, 5