Purpose: The aim of this study was to define if tadalafil causes detrusor muscle impairment and to observe the effect of combination of tadalafil with tamsulosin on the lower urinary tract of rats with bladder outlet obstruction (BOO) induced by chronic nitric oxide deficiency. Materials and Methods: Thirty-one male rats were randomized to following groups: 1 - control; 2 - L-Nitroarginine methyl ester (L-NAME)...