What medications are used to treat urinary frequency in men with Benign Prostatic Hyperplasia (BPH) or overactive bladder?

Medications for Urinary Frequency in Men

For men with urinary frequency, start with an alpha-blocker (such as tamsulosin 0.4 mg daily) as first-line therapy, and if storage symptoms persist, add either an antimuscarinic agent (such as solifenacin or tolterodine) or a beta-3 agonist (mirabegron 25-50 mg daily) as combination therapy. 1

First-Line Monotherapy

Alpha-blockers are the initial treatment for men with urinary frequency related to BPH:

• Tamsulosin, alfuzosin, doxazosin, or silodosin improve symptoms by 15-30% and increase urinary flow rates 2
• These agents work best in men with smaller prostates (<40 mL) 2
• Common side effects include dizziness, orthostatic hypotension, and ejaculatory dysfunction (especially with tamsulosin and silodosin) 2
• Warn patients undergoing cataract surgery about increased risk of intraoperative floppy iris syndrome 2

For men with larger prostates (>40 mL), add a 5-alpha-reductase inhibitor:

• Finasteride 5 mg daily or dutasteride 0.5 mg daily reduces prostate volume by 18-28% over months 2, 3
• These medications reduce risk of acute urinary retention by 57-68% and need for surgery by 55-64% at 4 years 2, 3
• Sexual side effects include decreased libido, erectile dysfunction, and reduced ejaculate volume 2, 3
• Clinical effect is slow and directly related to baseline prostate size 2

Combination Therapy for Persistent Storage Symptoms

When urinary frequency persists despite alpha-blocker therapy, add antimuscarinic or beta-3 agonist therapy:

Antimuscarinic Agents (Preferred for Urgency-Predominant Symptoms)

• Solifenacin, tolterodine, trospium, or oxybutynin can be added to alpha-blocker therapy 2, 1
• Check post-void residual (PVR) volume before starting—do not use if PVR >150 mL 1
• These agents significantly improve urgency, urge incontinence, and daytime frequency 2
• Combination of solifenacin 5 mg plus trospium 5 mg with tamsulosin reduced incontinence episodes from 3.4 to 0.9 per day in men with severe overactive bladder 4
• Side effects include dry mouth, constipation, and small increases in PVR, but urinary retention is rare when baseline PVR <150 mL 2

Beta-3 Agonists (Alternative with Better Tolerability)

• Mirabegron 25-50 mg daily improves frequency, urgency, and urge incontinence 2, 1
• Does not significantly affect voiding parameters or increase PVR 2
• Well tolerated in elderly men with multiple comorbidities 2
• Contraindicated in severe uncontrolled hypertension 2
• Side effects include hypertension, urinary tract infections, headache, and nasopharyngitis 2

Alternative Monotherapy Options

Phosphodiesterase-5 inhibitors (tadalafil 5 mg daily):

• Produces small reduction in International Prostate Symptom Score compared to placebo 2
• Improves erectile function simultaneously (IIEF score +3.6) 2
• Contraindicated with nitrates, recent stroke (<6 months), or significant cardiac disease 2
• Side effects include headache, flushing, dyspepsia, and nasal congestion 2

Monitoring and Safety Protocol

Before initiating antimuscarinic therapy:

• Measure post-void residual volume—avoid if >150 mL 1
• Document baseline International Prostate Symptom Score 1

During treatment:

• Reassess at 4-12 weeks to evaluate symptom response 1
• Monitor PVR and perform uroflowmetry during follow-up 1
• Instruct patients to discontinue antimuscarinics if voiding symptoms worsen 2

Specific Combination Regimens

Alpha-blocker + 5-ARI (for large prostates >40 mL):

• Combination of finasteride 5 mg plus doxazosin reduces symptom progression risk to 6.2% versus 17.4% with placebo 3
• Reduces acute urinary retention risk by 67% and surgery need by 64% 3
• Expect increased side effects: asthenia, postural hypotension, peripheral edema, and sexual dysfunction occur more frequently with combination 3

Alpha-blocker + antimuscarinic (for persistent storage symptoms):

• Tolterodine extended-release or solifenacin with tamsulosin significantly improves storage symptoms 2
• The NEPTUNE trial showed combination solifenacin plus tamsulosin improved both voiding and storage symptoms 2

Alpha-blocker + mirabegron (for storage symptoms with better tolerability):

• The MATCH and PLUS studies demonstrated mirabegron add-on to tamsulosin significantly improved overactive bladder symptoms 2
• Lower risk of urinary retention compared to antimuscarinics 2

Critical Pitfalls to Avoid

• Do not combine tadalafil 5 mg with alpha-blockers—offers no additional symptom improvement over monotherapy and increases side effects 2
• Do not use antimuscarinics as monotherapy in men with significant voiding symptoms—address obstruction with alpha-blockers first 1
• Do not prescribe antimuscarinics without checking PVR—risk of retention increases with elevated baseline PVR 1
• Do not expect immediate results from 5-ARIs—clinical effect requires months and depends on prostate size 2