I have a number of gastrointestinal conditions including pelvic floor disorder which causes my brain to send the wrong signals to the muscles "down there" when I go to the bathroom. This causes me to strain which has, in turn, caused me a lot of soreness in my back and shoulders. My muscles feel so tight that I think I might have actually pulled some muscles. Anyways, I take oxycodone on a regular basis for chronic abdominal pain as well. Just curious what, if any, effects tizanidine has had on constipation.