Benign prostatic hyperplasia (BPH) is an enlarged prostate gland. 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. The goals of treatment are to control symptoms, as evidenced by a minimum of a 3-point decrease in the AUA symptom index, prevent progression of BPH disease by reducing the risk of developing complications, and delay the need for surgical intervention. Drug therapy for BPH can be categorized into three types: agents that relax prostatic smooth muscle (reducing the dynamic factor), agents that interfere with testosterone's stimulatory effect on prostate gland enlargement (reducing the static factor), and agents that relax bladder detrusor muscle (improving the urine storage capacity of the bladder). Of the agents ...