FOUNDATION OVERVIEW: BENIGN PROSTATIC HYPERPLASIA
Benign prostatic hyperplasia (BPH) is the most common benign neoplasm in aging men. The prostate gland surrounds the urethra, the tube that carries urine from the bladder out of the body. As the prostate gets bigger, it may squeeze or partly block the urethra causing problems with urinating. The prostate begins to grow as men age, increasing the risk for BPH. Patients with BPH have increased smooth muscle tissue in the prostate containing α1-adrenergic receptors resulting in vasoconstriction and narrowing of the urethral lumen. Additionally, patients have physical obstruction symptoms resulting from an enlarged prostate.
Lower urinary tract symptoms (LUTS) suggestive of BPH alter bladder emptying or storage. Voiding symptoms are found early in the disease course and include urinary hesitancy, weak urinary stream, and the sensation of incomplete bladder emptying. Storage symptoms include urinary frequency, nocturia, urinary urgency, and urge incontinence. These symptoms occur after several years as the bladder smooth muscle hypertrophies and weaken. BPH increases the risk of urinary tract infections, bladder stones secondary to urinary stasis, and renal impairment. A serious complication of BPH is acute urinary retention, which often requires immediate catheterization.
Patients with LUTS should be referred to their physician as a detailed history and physical examination are necessary to exclude other possible etiologies, including prostate cancer, urinary tract infections, neurological or endocrine disorders. A digital rectal examination (DRE) determines the prostate size and can identify nodules suggestive of malignancy. A urinalysis excludes urinary tract infections or bladder stones. Pharmacists should be aware of medications that worsen LUTS. Examples include medications with anticholinergic properties such as antihistamines, tricyclic antidepressants, and opiates. Furthermore, as prostate tissue contains α1-adrenergic receptors, α-agonists such as pseudoephedrine or other decongestants exacerbate symptoms or attenuate therapy with α1-adrenergic antagonists.
BPH treatment depends on multiple factors: LUTS severity, concurrent medical illness that affects hemodynamic stability, prostate size, and presence of BPH-related complications. The American Urological Association (AUA) has a scoring system to rate BPH symptoms. Patients with mild BPH (AUA score of 0-7) are candidates for watchful waiting (if symptoms are not bothersome). This is a reasonable strategy as symptoms of BPH wax and wane and treatment may not be needed. If this strategy is used, patients should be monitored for worsening of symptoms indicating the need for pharmacologic treatment.
For patients with moderate to severe BPH (AUA score 8-35), α1-adrenergic antagonists are effective in reducing LUTS (Table 65-1). This class of medications improves voiding symptoms by relaxing prostatic smooth muscle tissue, thereby allowing passage of urine through the urethra. However, they do not reduce the prostate size or prevent progression of BPH. The primary distinction between α1-adrenergic antagonists is their selectivity for the α1A-adrenergic receptor, which ultimately affects tolerability. ...