At a baseline maximum urinary flow rate of greater than 15 ml per second in 128 patients the median flow rate change was -2.1 and -0.8 ml per second ( p = 0.246 ) , at a maximum of 10 to 15 ml per second in 522 the change was 0.2 and 0.8 ml per second ( p = 0.044 ) , and at a maximum of less than 10 ml per second in 547 the change was 1.2 and 1.8 ml per second ( p = 0.189 ) for placebo and tadalafil , respectively .