The effect of udenafil on the hemodynamics of healthy male volunteers administered tamsulosin

Objective: The purpose of this study is to evaluate the hemodynamic interactions between udenafil and tamsulosin. Methods: After a placebo lead-in period, 27 healthy volunteers received 200 mg udenafil + tamsulosin placebo, udenafil placebo +0.4 mg tamsulosin, or 200 mg udenafil +0.4 mg tamsulosin. Blood pressure and pulse rate (PR) were measured at 15 time points from 0 to 24 hours. Results: A single dose of udenafil, when administered with multiple tamsulosin doses, produced statistically significant increases in PR (mean: 10.7; 95% confidence interval: 5.3, 16.2 bpm; p < 0.001) compared with tamsulosin administered with an udenafil placebo. Systolic and diastolic blood pressure measurements remained unchanged. Two subjects who took udenafil with tamsulosin had a decrease in standing systolic blood pressure (SBP) greater than 30 mmHg in comparison to their baseline SBP; however, compared with the frequency of a decrease in standing SBP greater than 30 mmHg in comparison to the baseline, there was no significant difference in frequency among the four treatments (p = 0.243). There was no difference in the Cmax, AUClast, or AUCinf of udenafil and its active metabolite DA-8164 between the administration of udenafil and udenafil with tamsulosin. Conclusion: The coadministration of udenafil and tamsulosin was not associated with clinically significant hemodynamic changes in healthy volunteers. Although this study was conducted on a small number of healthy young subjects, the use of udenafil for the treatment of erectile dysfunction in patients taking tamsulosin for the treatment of benign prostatic hyperplasia is not expected to cause significant safety problems.