EFFECT OF TADALAFIL THAT WAS ADDITIONALLY ADMINISTERED TO PATIENTS RECEIVING AN ALPHA1-BLOCKER IN JAPANESE MEN WITH LOWER URINARY TRACT SYMPTOMS SUGGESTIVE OF BENIGN PROSTATIC HYPERPLASIA

(Objectives) Alpha1-blockers have been widely used for the treatment of lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH). As improvement of symptoms occur relatively early after the administration of alpha-1 blockers, the blockers are considered to be extremely beneficial. However, some patients respond poorly to the blockers, providing additional treatment is difficult. Here we examined the efficacy of tadalafil that was additionally administered to patients receiving an oral alpha-1 blocker. (Subjects and methods) The subjects were patients who had been diagnosed with BPH/LUTS, had received an oral alpha1-blocker for at least 1 month, and had responded poorly to the alpha-1 blocker treatment (International Prostate Symptom Score IPSS ≥8 and/or QOL index ≥3). Tadalafil 5 mg was administered on consecutive days to patients orally receiving an alpha-1 blocker. The following were measured before and at 4 and 8 weeks after the administration of tadalafil to evaluate the add-on effect of Tadalafil: IPSS, QOL index, Overactive Bladder Symptom Score (OABSS), maximal urinary flow rate, residual urine volume, and International Index of Erectile Function-5 (IIEF-5). (Results) We studied 41 patients until 8 weeks after the drug administration. Tadalafil produced significant improvement in IPSS, QOL index, OABSS, and IIEF-5 at 4 weeks after the administration, as compared with before administration (P < 0.05). The improvement was even more significant at 8 weeks. However, the maximal urinary flow rate or residual urine volume did not differ significantly at any time point. (Conclusions) The results of this study revealed that additional administration of tadalafil improves not only urinary conditions but also sexual function in patients with BPH/LUTS.