# Benign Prostatic Hyperplasia: Medical Management

## Introduction

Benign prostatic hyperplasia (BPH) is a histologic diagnosis characterized by non-malignant proliferation of prostatic stromal and epithelial cells, leading to lower urinary tract symptoms (LUTS) in aging men. It affects approximately 50% of men by age 60 and up to 90% by age 85. Medical management is the first-line approach for most symptomatic patients.

## Pathophysiology

BPH involves both static and dynamic components of obstruction. The static component results from glandular enlargement compressing the urethra, while the dynamic component involves smooth muscle tone in the prostatic stroma and bladder neck. Testosterone is converted to dihydrotestosterone (DHT) by 5-alpha reductase in the prostate, and DHT drives glandular growth. Alpha-1 adrenergic receptors mediate smooth muscle contraction in the prostate and bladder neck. Chronic obstruction leads to detrusor muscle hypertrophy and eventually detrusor failure.

## Clinical Presentation

### Lower Urinary Tract Symptoms (LUTS)

Storage (irritative) symptoms include frequency, urgency, nocturia, and urge incontinence. Voiding (obstructive) symptoms include weak stream, hesitancy, intermittency, straining, sensation of incomplete emptying, and post-void dribbling. Symptoms are assessed using the International Prostate Symptom Score (IPSS), where scores of 0 to 7 indicate mild, 8 to 19 moderate, and 20 to 35 severe symptoms. LUTS significantly impact quality of life and sleep.

### Complications

Complications include acute urinary retention requiring catheterization, recurrent urinary tract infections, bladder stones, chronic kidney disease from bilateral hydronephrosis (rare), and gross hematuria from prostatic venous congestion.

## Evaluation

### History and Physical

LUTS should be characterized using the IPSS questionnaire. Medications that exacerbate symptoms, including anticholinergics, decongestants (alpha-agonists), diuretics, and opioids, should be reviewed. Digital rectal exam (DRE) assesses prostate size, consistency, and symmetry, with hard nodules suggesting malignancy. A focused neurologic exam is indicated if neurogenic bladder is suspected.

### Laboratory and Diagnostic Testing

Urinalysis rules out infection and hematuria. PSA testing involves shared decision-making for prostate cancer screening, and PSA also correlates with prostate volume. Serum creatinine is checked if obstruction or renal impairment is suspected. Post-void residual (PVR) measured by bladder scan or catheterization provides objective data, with elevated PVR greater than 200 mL suggesting significant obstruction. Uroflowmetry measures peak urinary flow rate (Qmax), with less than 10 mL per second suggesting obstruction. Renal ultrasound is obtained if there is concern for hydronephrosis but is not routinely indicated.

![The International Prostate Symptom Score questionnaire with severity classification](images/ipss-questionnaire.jpg)

## Watchful Waiting

Watchful waiting is appropriate for patients with mild symptoms (IPSS 0 to 7) and no complications. Lifestyle modifications include reducing evening fluid intake to minimize nocturia, limiting caffeine and alcohol, using the double voiding technique (void, wait, then void again), timed voiding every 2 to 3 hours, and reviewing and modifying contributing medications. Symptoms are reassessed every 6 to 12 months.

## Pharmacotherapy

### Alpha-1 Adrenergic Blockers (First-Line)

| Drug Class | Examples | Mechanism | Onset | Key Side Effects |
|------------|----------|-----------|-------|-----------------|
| Alpha-1 blockers | Tamsulosin 0.4 mg, silodosin 8 mg, alfuzosin 10 mg | Relax prostatic/bladder neck smooth muscle | Days to 2 weeks | Orthostatic hypotension, dizziness, retrograde ejaculation |
| 5-Alpha reductase inhibitors | Finasteride 5 mg, dutasteride 0.5 mg | Block testosterone→DHT; reduce prostate size 20-30% | 3-6 months | Sexual dysfunction, gynecomastia; halves PSA |
| PDE5 inhibitors | Tadalafil 5 mg daily | Smooth muscle relaxation | 1-2 weeks | Headache, flushing; also treats ED |
| Anticholinergics (add-on) | Tolterodine, solifenacin | Reduce detrusor overactivity | 1-2 weeks | Dry mouth, constipation; check PVR first |
| Beta-3 agonist (add-on) | Mirabegron 25-50 mg | Bladder relaxation | 4-8 weeks | Hypertension, UTI |

Alpha-blockers relax smooth muscle in the prostatic stroma and bladder neck, addressing the dynamic component of obstruction. Agents include tamsulosin (0.4 mg daily), silodosin (8 mg daily), alfuzosin (10 mg daily), doxazosin, and terazosin. Onset of effect occurs within days to 2 weeks. Side effects include orthostatic hypotension (less common with tamsulosin and silodosin), dizziness, and retrograde ejaculation. Intraoperative floppy iris syndrome is a concern, and ophthalmologists should be informed before cataract surgery. Tamsulosin is the most commonly prescribed agent due to its uroselectivity and fewer cardiovascular effects.

### 5-Alpha Reductase Inhibitors (5-ARIs)

5-ARIs block the conversion of testosterone to DHT, reducing prostate volume by 20 to 30% over 6 to 12 months. Agents include finasteride (5 mg daily) and dutasteride (0.5 mg daily). Onset of effect is 3 to 6 months for symptom improvement, with full effect at 12 months. These agents are best suited for patients with large prostates (greater than 30 to 40 g) and elevated PSA. Side effects include sexual dysfunction (decreased libido, erectile dysfunction, decreased ejaculate volume) and gynecomastia. 5-ARIs reduce PSA by approximately 50%, so measured PSA should be multiplied by 2 when screening for prostate cancer. They reduce the risk of acute urinary retention and the need for surgery.

### Combination Therapy

Combination therapy with an alpha-blocker and a 5-ARI is more effective than either agent alone for men with moderate-to-severe symptoms and prostatic enlargement. The MTOPS and CombAT trials demonstrated superior symptom improvement and reduced disease progression with combination therapy. This approach should be considered for patients with large prostates and significant symptoms who are at risk for progression.

### Phosphodiesterase-5 Inhibitors

Tadalafil 5 mg daily is FDA-approved for BPH/LUTS and also treats concurrent erectile dysfunction. It relaxes smooth muscle in the prostate, bladder, and urethra via the nitric oxide/cGMP pathway. It can be combined with alpha-blockers but should be avoided with doxazosin and terazosin due to hypotension risk. Tadalafil is particularly appropriate when BPH and erectile dysfunction coexist.

### Anticholinergics and Beta-3 Agonists

These agents are considered for storage-predominant symptoms (urgency, frequency) not adequately controlled by alpha-blockers. Mirabegron (a beta-3 agonist) is preferred due to fewer side effects than anticholinergics. Anticholinergics should be used cautiously because they can worsen urinary retention in patients with significant obstruction. PVR should be monitored when adding these agents.

![Comparison table of BPH medications including mechanism, onset, key side effects, and best candidates](images/bph-medication-comparison.jpg)

## Referral to Urology

Urology referral is indicated for refractory symptoms despite optimized medical therapy, recurrent urinary retention, recurrent UTIs or bladder stones, hematuria requiring further evaluation, elevated PVR (greater than 200 to 300 mL) or evidence of upper tract obstruction, patient preference for surgical options, and abnormal DRE or PSA concerning for prostate cancer.

## Surgical Options (Overview)

Transurethral resection of the prostate (TURP) remains the gold standard surgical treatment. Laser enucleation (HoLEP) and vaporization techniques are alternatives. Minimally invasive options include UroLift (prostatic urethral lift), Rezum (water vapor therapy), and aquablation. Prostatectomy, either open or robotic, is reserved for very large prostates (greater than 80 to 100 g).

![Flowchart showing the stepwise management of BPH from watchful waiting through pharmacotherapy to surgical referral](images/bph-management-algorithm.jpg)

## Key Clinical Pearls

Alpha-blockers should be started first for rapid symptom relief, with a 5-ARI added for patients with large prostates to reduce long-term progression risk. 5-ARIs take 3 to 6 months for effect and reduce PSA by 50%, which must always be accounted for when interpreting PSA results. Patients should be counseled about intraoperative floppy iris syndrome with tamsulosin before any planned cataract surgery. Tadalafil 5 mg daily is an excellent option for patients with concurrent BPH and erectile dysfunction.

## References

1. AUA Guideline: Management of Benign Prostatic Hyperplasia (BPH). American Urological Association, 2021.
2. McConnell JD, et al. The long-term effect of doxazosin, finasteride, and combination therapy on the clinical progression of BPH (MTOPS). *N Engl J Med*. 2003;349(25):2387-2398.
3. Roehrborn CG, et al. The effects of combination therapy with dutasteride and tamsulosin on clinical outcomes in men with symptomatic BPH (CombAT). *Eur Urol*. 2010;57(1):123-131.
4. Oelke M, et al. EAU guidelines on the treatment and follow-up of non-neurogenic male LUTS. *Eur Urol*. 2013;64(1):118-140.