Chapter 104: Benign Prostatic Hyperplasia

KEY CONCEPTS

• Although symptomatic benign prostatic hyperplasia (BPH) is rare in men younger than 50 years, it is common in men aged 60 years and older. Prostate growth is androgen-dependent. Symptoms commonly result from both static and dynamic factors.

• BPH symptoms may be exacerbated by medications, including antihistamines, phenothiazines, tricyclic antidepressants, and anticholinergic agents. In these cases, discontinuing the causative agent can relieve symptoms.

• For patients with mild disease who are asymptomatic or have mildly bothersome symptoms and no complications of BPH disease, watchful waiting is indicated. Watchful waiting includes behavior modification, lifestyle modification, discontinuation of medications that contribute to voiding symptoms, and return visits to the physician at 6- or 12-month intervals for assessment of worsening symptoms or signs of bladder outlet obstruction.

• If symptoms progress to a moderate or severe level, drug therapy or surgery is indicated. α₁-Adrenergic antagonists quickly relieve voiding symptoms, but do not prevent disease progression. 5α-Reductase inhibitors delay symptom progression and reduce the incidence of BPH-related complications in patients with prostates of at least 30 to 40 g, but may not reduce voiding symptoms for 3 to 6 months.

• All α₁-adrenergic antagonists are equally effective in relieving BPH symptoms. Older second-generation immediate-release formulations of α₁-adrenergic antagonists (eg, terazosin, doxazosin) can cause adverse cardiovascular effects, mainly first-dose syncope, orthostatic hypotension, and dizziness. For patients who cannot tolerate these hypotensive adverse effects, a third-generation, pharmacologically uroselective α_1A-adrenergic antagonist (eg, tamsulosin, silodosin) or an extended-release formulation of alfuzosin, a second-generation, functionally uroselective agent, is a good alternative.

• 5α-Reductase inhibitors are useful primarily for patients with large prostates greater than 40 g who wish to avoid surgery and cannot tolerate the side effects of α₁-adrenergic antagonists. 5α-Reductase inhibitors have a slow onset of action, taking up to 6 months to exert maximal clinical effects, which is a disadvantage of their use, especially as single-drug therapy for BPH. In addition, decreased libido, erectile dysfunction, and ejaculation disorders are common adverse effects, which may be troublesome in sexually active patients.

• Phosphodiesterase type 5 inhibitors can be used in patients with moderate-to-severe BPH and erectile dysfunction. They improve obstructive and irritative voiding symptoms, but do not significantly increase urinary flow rate or reduce postvoid residual (PVR) urine volume. Hence, a phosphodiesterase type 5 inhibitor is considered less effective than an α-adrenergic antagonist for BPH. A phosphodiesterase type 5 inhibitor may be used alone; however, symptom improvement and an increase in peak urinary flow rate have been demonstrated when it is used along with an α-adrenergic antagonist or a 5α-reductase inhibitor.

• Anticholinergic agents are indicated in patients with moderate-to-severe lower urinary tract symptoms (LUTS) with a predominance of irritative voiding symptoms. In this case, the drugs are commonly added to an existing ...