 Selective alpha @-@ 1 blockers have a variety of uses . Because one of their effects is to relax the muscles in the neck of the bladder , they are often used to treat benign prostatic hyperplasia , and to help with the expulsion of bladder stones . Their effects on the central nervous system make them useful for treating generalized anxiety disorder , panic disorder , and posttraumatic stress disorder . They may , however , have significant side @-@ effects , including a drop in blood pressure . 
