Management of Benign Prostatic Hyperplasia (BPH): Pharmacotherapy

Posted by admin on February 14th, 2010 No Comments

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Pharmacotherapy: Alpha-Adrenergic Blockers

Pharmacologic agents designed to relax prostatic smooth muscle (alpha-adrenergic blockers) and reduce prostatic size (androgen suppression) have been reported to be safe and effective in treating benign prostatic hyperplasia (BPH). The selective alpha-1 blockers doxazosin and terazosin, and the 5-alpha reductase inhibitor finasteride, have been approved by the FDA for the treatment of BPH. Patients with clinically significant BPH are candidates for pharmacotherapy unless they are experiencing severe symptomatology (e.g., serious urinary retention). These agents are reported to improve symptoms of benign prostatic hyperplasia (BPH) with minimal morbidity at a substantial cost savings relative to TURP.

Pharmacotherapy: Alpha-Adrenergic Blockers

Alpha-1 adrenergic blockers prazosin (Minipress), terazosin (Hytrin) and doxazosin (Cardura) have all been extensively studied in patients with benign prostatic hyperplasia (BPH). These agents relax smooth muscle at the bladder neck and prostatic urethra, offering symptomatic improvement in a relatively short period of time.

Although prazosin has demonstrated efficacy in patients with BPH, it has fallen out of favor since it is short-acting, requiring multiple daily dosing. Terazosin has been studied extensively and has consistently demonstrated efficacy. Patients on terazosin, frequently titrated to doses of 10 mg once daily, show an increase in peak urinary flow rate (PUFR) and a decrease in their symptoms. Doxazosin, although not studied as extensively as terazosin, has also demonstrated similar efficacy in this patient population. Similar agents studied outside the United States, such as tamsulosin and alfuzosin, have demonstrated some efficacy.

The long-acting alpha-1 blockers terazosin and doxazosin are frequently used to treat common comorbid disease states such as hypertension. Occasionally, however, the maximum dose of an alpha-1 blocker necessary to treat benign prostatic hyperplasia (BPH) in normotensive men cannot be achieved due to the risk of hypotension developing. However, studies have demonstrated that alpha-1 blockade will significantly lower blood pressure in patients with BPH who are hypertensive; yet in normotensive BPH patients, the blood pressure is not significantly decreased. Common dosages employed for alpha-1 antagonists in BPH and hypertension can be found in Table 3. Additionally, alpha-1 blockers have a favorable effect on the lipoprotein profile by slightly lowering LDL and VLDL, and increasing HDL, thereby decreasing the risk for coronary artery disease.

Table 3 Common Dosages Utilized for Alpha-1 Antagonists in BPH and Hypertension
Drug	Dose for BPH	Dose for Hypertension
Prazosin	2 mg BID to TID	6 mg to 15 mg divided 2 to 3 times daily
Doxazosin	2 mg to 8 mg QD	2 mg to 16 mg QD
Terazosin	5 mg to 10 mg QD	2 mg to 5 mg QD

Approximately 10%–15% of patients receiving an alpha-1 blocker develop a clinically significant adverse event. Side effects such as dizziness, headache, asthenia, syncope and hypotension have been reported, especially after the first dose. In order to minimize this “first dose” effect, it is important to take the once-daily dose at bedtime, titrating upwards slowly.

Alpha Blockers Overview Hyperplasia of the stromal tissue may or may not lead to significant enlargement of the prostate, but it usually leads to dynamic benign prostatic hyperplasia by increasing prostatic smooth muscle, which triggers increased smooth-muscle tension and resistance to urine flow. (The dynamic and ...
Benign Prostatic Hyperplasia: Alpha Blockers Overview Numerous alpha blockers have been approved for the treatment of benign prostatic hyperplasia in the major pharmaceutical markets (United States, France, Germany, Italy, Spain, United Kingdom, and Japan), largely replacing the need for surgical treatment in the past ten years. Alpha blockers, with ...
Terazosin Terazosin (Abbott's Hytrin, generics) is a long-acting, alpha1-adrenergic-receptor blocker with a prolonged half-life that permits once-daily dosing. Abbott markets terazosin in the United States and several European countries; Mitsubishi-Tokyo Pharmaceuticals is the licensee in Japan. In March 2000, the FDA granted Mylan approval ...
Cardiovascular Effects By blocking the alpha-1 adrenoceptor, these drugs cause peripheral vasodilation, which reduces total peripheral vascular resistance and thereby lowers high blood pressure. Indeed, reduction in blood pressure was the primary indication for which alpha-1 adrenoceptor antagonists were developed. The effects of selective alpha-1 blockade ...
Drug Interactions in the Treatment of ED, LUTS and BPH: Selective Alpha-1-Adrenergic Receptor Blockers Pharmacodynamics Alpha1 receptors are located in nonvascular smooth muscles (e.g., bladder trigone and sphincters, gastrointestinal tract and sphincters, prostate adenoma and capsule, and ureters) and in nonmuscular tissues (e.g., central nervous system, liver, and kidneys). Symptoms of benign prostatic hyperplasia (BPH) are related to bladder ...

Tags: Alfuzosin, Cardura, Doxazosin, Finasteride, Hytrin, Minipress, Prazosin, Tamsulosin, Terazosin
Posted in: Management

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