Reviews for Primary Care - Fall 2007 - (Page 7) Alpha Blockers for BPH Treatment that tamsulosin causes anejaculation rather than retrograde ejaculation.50 The mechanism for the increased incidence of ejaculatory dysfunction associated with tamsulosin has been attributed to its affinity for dopaminergic and other central nervous system receptors.50,51 Selective alpha blockers like prazosin offered the advantage of improved tolerability over nonselective alpha blockers like phenoxybenzamine. The long-acting selective alpha 1 blockers like terazosin and doxazosin offered the convenience of once a day dosing with better tolerability compared with the shorter-acting agents like prazosin. Tamsulosin achieved a therapeutic effect without the need for dose titration and with minimal effects on blood pressure. The convenience of eliminating the dose titration came at the expense of ejaculatory dysfunction. Therefore, there was a need for a long-acting selective alpha 1 blocker that did not require dose titration, had minimal side effects on blood pressure, and had no effects on ejaculatory function (retrograde ejaculation or anejaculation). Alfuzosin 10 mg OD is the fourth alpha 1 selective blocker approved by the FDA for the treatment of symptomatic BPH. Radioligand binding studies failed to show any receptor selectivity of alfuzosin for the alpha 1 subtypes.45,46 The excellent tolerance has been attributed to its slow release formulation. Two randomized, placebo-controlled trials were conducted as part of the NDA for the approval of alfuzosin in the United States for the treatment of symptomatic BPH (Figure 4, Table 7).53,54 Alfuzosin 10 mg achieved a clinically significant improvement in LUTS without dose titration. The AUA Guidelines Committee concluded that alfuzosin has comparable clinical efficacy to tamsulosin and the other approved alpha blockers but does not cause ejaculatory dysfunction.55 Alpha Blockers for Treating Acute Urinary Retention Acute urinary retention is a potentially life threatening consequence of BPH. The initial management of acute urinary retention is to temporarily insert an indwelling urinary catheter. The catheter is typically removed in a few days in order to attempt a trial of voiding without a catheter. A randomized, double-blind, placebo-controlled study has shown that alfuzosin increases the likelihood of successfully removing the catheter while also decreasing the risk of a subsequent Table 7 Alfuzosin: Adverse Effects52 Alfuzosin (n 473) Upper respiratory tract infection Dizziness Headache Fatigue 3.0% 5.7% 3.0% 2.7% Placebo (n 678) 0.6% 2.8% 1.8% 1.8% Figure 4. The effect of alfuzosin on lower urinary tract symptoms and peak flow rate relative to placebo.52 Qmax, peak urinary flow. Alfuzosin 10 mg/day Mean Change in Symptom Score Mean Change in Qmax (mL/s) 4 P P 2 1.7 1.4 1 0.2 0 Study 1 N 337 Study 2 N 283 .0004 2.3 .03 0 Placebo 3 2 1.6 4 3.6 P .001 6.9 4.9 P .002 6 8 Study 1 N 337 Study 2 N 289 VOL. 1 NO. 1 2007 REVIEWS FOR PRIMARY CARE 7
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.