Effect of tamsulosin on the pharmacokinetics of dutasteride in Chinese male healthy volunteers.

The purpose of this study was to evaluate the effect of tamsulosin (0.2 mg) on the pharmacokinetics of dutasteride (0.5 mg) in a group of healthy Chinese male volunteers. This was an open-label, single-sequence, 3-period, drug-drug interaction phase 1 study. Twenty-four healthy Chinese male volunteers were enrolled and administered a single dose of 0.5 mg dutasteride and, following a 28- to 30-day washout period, 0.2 mg tamsulosin once daily for 7 days. On day 5, subjects received 0.2 mg tamsulosin coadministered with 0.5 mg dutasteride. Serum dutasteride and tamsulosin concentrations were monitored. In the presence or absence of tamsulosin, there were no apparent changes in dutasteride AUC and Cmax . Adverse events reported were mild to moderate in intensity and resolved by the end of the study. In healthy Chinese male volunteers, tamsulosin 0.2 mg at steady state had no apparent effect on dutasteride pharmacokinetics. Dutasteride and tamsulosin when administered alone or in combination were well tolerated.