Whe pharmacokinetics of bunazosin 6 mg sustained-release tablet (E 1015) compared with that of the standard 2 mg sugar-coated plain tablet (Detantol (R)), and the effect of food on the plasma concentrations of bunazosin after E 1015 administration were studied. Twelve healthy volunteers received one Detantol (R) (2 mg) after breakfast, one E 1015 (6 mg) after breakfast or E 1015 (6 mg) in a fasting condition in a randomized crossover study with one-week intervals. The plasma and urine concentrations of bunazosin, and the serum protein binding were measured. The subjects reported a number of complaints, including headache, dizziness, nasal congestion. No clear difference in the number of complaints among treatments were observed. No clinically significant changes that were considered drug related were noted in the electrocardiograms, clinical laboratory test results and vital signs.