The erectile dysfunction drug tadalafil has been approved for treatment of the signs and symptoms of benign prostatic hyperplasia, the Food and Drug Administration announced on Oct. 6.
Tadalafil, the phosphodiesterase-5 (PDE5) inhibitor marketed as Cialis by Eli Lilly, was also approved for treating BPH and erectile dysfunction (ED), when they occur simultaneously, according to the FDA statement. The agency first approved tadalafil for treating erectile dysfunction in 2003.
Men with BPH have an enlarged prostate, which can cause symptoms ranging from difficulty urinating and a weak urine stream to a sudden urge to urinate and more frequent urination.
In two studies of men with BPH, those treated with 5 mg/day of tadalafil experienced statistically significant improvements in symptoms, as indicated by reductions in the total International Prostate Symptom Score (IPSS), when compared with the score in men who received a placebo.
Similarly, in a placebo-controlled study of men with both ED and BPH, those treated with 5 mg/day of tadalafil had improvements in symptoms of both conditions, with the ED improvement measured by the erectile function domain score of the International Index of Erectile Function.
The FDA noted that tadalafil is contraindicated in patients taking nitrates, such as nitroglycerin, because it has been shown to potentiate the hypotensive effects of nitrates. In addition, combining tadalafil with alpha-blockers for treating BPH "is not recommended because the combination has not been adequately studied for the treatment of BPH, and there is a risk of lowering blood pressure," the statement said.
Tadalafil is the first PDE5 inhibitor to be approved for BPH. The eight drugs previously approved for treating BPH symptoms are the 5-alpha reductase inhibitors finasteride (Proscar) and dutasteride (Avodart); alpha-blockers terazosin (Hytrin), doxazosin (Cardura), tamsulosin (Flomax), alfuzosin (Uroxatral), and silodosin (Rapaflo); and the combination of dutasteride plus tamsulosin (Jalyn).