Benign Prostatic Hyperplasia (BPH): Pharmacologic Management with Alpha-Blockers and 5-ARIs

Drug	Dose	Route & Frequency	Duration	Indication
Terazosin (α₁-adrenergic blocker)	Start 1 mg hs, increase gradually to 5–10 mg hs	po hs (by mouth, at bedtime)	Long-term; reassess after 4–6 weeks	First-line for LUTS relief — relaxes smooth muscle in prostate and bladder neck to improve urinary flow
OR
Doxazosin (α₁-adrenergic blocker)	Start 4 mg → titrate up to 8 mg po hs	po hs (by mouth, at bedtime)	Long-term; reassess after 4–6 weeks	Alternative α₁-blocker for symptomatic relief when Tamsulosin is unavailable; also lowers BP
AND
Finasteride (5-α reductase inhibitor)	5 mg po od	po od (once daily, with or without food)	6–12 months minimum	Reduces prostate size (>40 mL) by inhibiting testosterone → DHT conversion, prevents disease progression and acute urinary retention

Tamsulosin (0.4 mg) 1×1 po hs

or

Doxazosin (4 mg) 1×1 po hs

AND Finasteride (5 mg) 1×1 po od

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Introduction

Benign Prostatic Hyperplasia (BPH) is a nonmalignant enlargement of the prostate gland commonly affecting men aged over 50 years. The enlargement leads to bladder outlet obstruction (BOO), resulting in lower urinary tract symptoms (LUTS) such as frequency, urgency, nocturia, weak urinary stream, and incomplete emptying.

The primary goal of management is to relieve symptoms, prevent progression, and avoid complications like urinary retention, infection, or renal failure.

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Pathophysiology

BPH is due to stromal and epithelial proliferation in the transitional zone of the prostate under the influence of dihydrotestosterone (DHT) — the active metabolite of testosterone produced by 5-alpha reductase enzyme. The enlargement causes mechanical obstruction (static component) and increased smooth muscle tone mediated by α-adrenergic receptors (dynamic component). Hence, both hormonal suppression and smooth muscle relaxation are targeted in treatment.

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Pharmacologic Therapy (First-Line Treatment)

Treatment selection depends on prostate size, severity of symptoms, and patient preference. Pharmacologic therapy remains the cornerstone for mild-to-moderate BPH before considering surgical intervention.

1. α-1 Adrenergic Blockers

(For rapid symptomatic relief regardless of prostate size)

These agents relax smooth muscle in the bladder neck, prostate capsule, and prostatic urethra, reducing urethral resistance and improving urinary flow.

Example Regimen:

• Tamsulosin (0.4 mg) 1×1 po pc (after meals) daily

  • ⏱ Duration: Long-term; reassess after 4–6 weeks

  • 💡 Mechanism: Selective α1A receptor blockade → smooth muscle relaxation in prostate and bladder neck

  • ⚠️ Adverse effects: Dizziness, orthostatic hypotension, retrograde ejaculation, rhinitis

Alternative α-blockers:

Drug	Dose	Frequency	Route	Notes
Alfuzosin	10 mg	po pc od	Once daily	Good cardiovascular safety profile
Doxazosin	4 mg → titrate to 8 mg	po pc od	Start low to avoid hypotension
Terazosin	5 mg → increase to 10 mg	po hs	Titrate slowly due to first-dose syncope

Clinical Note:

• α-blockers improve symptoms within days to weeks.

• They do not reduce prostate volume or prevent disease progression.

2. 5-Alpha Reductase Inhibitors (5-ARIs)

(For prostates > 40 mL or PSA > 1.5 ng/mL)

These drugs block the conversion of testosterone to DHT, leading to a 20–30% reduction in prostate volume and improvement in urinary flow over 6–12 months.

Example Regimen:

• Finasteride (5 mg) 1×1 po od (daily)

  • ⏱ Duration: Minimum 6–12 months for noticeable improvement

  • 💡 Mechanism: Type II 5-alpha reductase inhibition → decreases DHT production

  • ⚠️ Adverse effects: Decreased libido, erectile dysfunction, gynecomastia

Alternative:

• Dutasteride (0.5 mg po od) – inhibits both Type I and II 5α-reductase, leading to greater DHT suppression.

Clinical Note:

• Benefits are most evident in patients with large prostates and elevated PSA.

• Reduces risk of acute urinary retention and need for surgery by up to 50%.
  

3. Combination Therapy

(For moderate to severe LUTS with enlarged prostate)

Rationale: Addresses both dynamic (muscle tone) and static (prostate enlargement) components of obstruction.

Example Regimen:

• Tamsulosin (0.4 mg) + Finasteride (5 mg) po od

  • ⏱ Duration: 6–12 months

  • 💡 Effect: Faster symptom relief and greater long-term reduction in prostate volume and progression.

Key Evidence:

• MTOPS Trial (NEJM, 2003): Combination therapy reduced clinical progression of BPH by 66% compared to monotherapy.
  

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Non-Pharmacologic / Surgical Options

When medical management fails or complications develop, surgical intervention is indicated.

Transurethral Resection of the Prostate (TURP)

• Gold standard for surgical treatment of BPH.

• Removes obstructing prostatic tissue using a resectoscope via the urethra.
  

Indications for Surgery:

✅ Refractory urinary retention ✅ Recurrent urinary tract infection ✅ Bladder stones ✅ Gross hematuria secondary to BPH ✅ Renal insufficiency due to chronic obstruction ✅ Severe symptoms unresponsive to medical therapy

Postoperative Care:

• Continuous bladder irrigation (CBI) to prevent clot retention

• Foley catheter for 1–3 days post-procedure

• Monitor for TURP syndrome (hyponatremia, confusion, hypertension)

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Duration and Monitoring

Therapy	Reassessment	Key Monitoring
α-blocker	4–6 weeks	Blood pressure, LUTS improvement
5-ARI	6–12 months	PSA level, prostate volume
Combination	6 months	Symptom score (IPSS), PVR, urinary flow rate

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Follow-up Plan

• First follow-up: 4–6 weeks after initiating therapy

• Subsequent visits: Every 3–6 months to assess symptom control and side effects

• Annual review: Digital Rectal Exam (DRE) + PSA (if indicated)

• Reevaluate therapy if:

  • No improvement after 6 months

  • New complications (UTI, hematuria, retention)

  • Suspicion of malignancy
    

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Patient Counseling

• Explain that BPH is a benign condition, not prostate cancer.

• Encourage adherence to medication, as effects may take weeks (α-blockers) to months (5-ARI).

• Warn about common side effects and when to report them.

• Advise on lifestyle modifications:

  • Limit evening fluid intake

  • Avoid caffeine and alcohol

  • Empty bladder regularly (double voiding)

  • Avoid decongestants and anticholinergic drugs
    

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Summary Table

Drug Class	Example (Generic Name)	Dose	Frequency / Route	Duration	Mechanism of Action	Key Side Effects / Precautions
α-1 Adrenergic Blocker	Tamsulosin	0.4 mg	po pc od (once daily after meals)	Long-term (reassess after 4–6 weeks)	Selective α₁A receptor blockade → relaxes smooth muscle in the prostate and bladder neck → improves urinary flow and reduces dynamic obstruction	Dizziness, postural hypotension, rhinitis, retrograde ejaculation
Alternative α-blockers	Alfuzosin / Doxazosin / Terazosin	Alfuzosin 10 mg / Doxazosin 4–8 mg / Terazosin 5–10 mg	po pc od or hs	Long-term	Non-selective α₁ blockade → smooth muscle relaxation in prostate and vascular smooth muscle	Orthostatic hypotension (especially first dose), fatigue
5-Alpha Reductase Inhibitor (5-ARI)	Finasteride	5 mg	po od (once daily)	6–12 months (for full effect)	Inhibits Type II 5-α-reductase → ↓ conversion of testosterone to DHT → ↓ prostate volume (20–30%), ↓ LUTS progression	Decreased libido, erectile dysfunction, gynecomastia
Alternative 5-ARI	Dutasteride	0.5 mg	po od	6–12 months	Inhibits both Type I and II 5-α-reductase → more profound suppression of DHT	Same as Finasteride
Combination Therapy	Tamsulosin + Finasteride	0.4 mg + 5 mg	po od	6–12 months	Dual mechanism: α-blocker provides immediate relief; 5-ARI prevents progression by reducing prostate size	Additive side effects (sexual dysfunction, hypotension)
Add-on for irritative LUTS (if PVR <150 mL)	Tolterodine / Oxybutynin	Tolterodine 2 mg / Oxybutynin 5 mg	po bid	Symptom-based, reassess every 3 months	Antimuscarinic → reduces detrusor overactivity	Dry mouth, constipation, urinary retention risk

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Conclusion

The management of BPH requires a tailored approach based on prostate size, severity of symptoms, and patient tolerance.

• Mild cases: lifestyle + α-blocker monotherapy

• Moderate to severe: combination therapy

• Refractory or complicated: surgical intervention (TURP)

With proper pharmacologic and supportive management, most patients achieve significant symptom relief and improved quality of life.

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References

1. American Urological Association (AUA) Guidelines: Management of Benign Prostatic Hyperplasia (2023)

2. European Association of Urology (EAU) Guidelines: Male LUTS Including BPH (2023)

3. Thai Clinical Practice Guideline (CPG) for BPH (2022)

4. McConnell JD et al., NEJM, 2003 — MTOPS Trial

5. Abrams P, Chapple CR, et al., Eur Urol, 2014 — Combination Therapy Efficacy