I've had the same problem and found that Senna leaves works better than anything else I've tried. I get them at my health food grocery (Whole Foods) in a tea bag (
Welcome to Alvita) and drink it before I go to bed. I can control the strength by how long I let it steep. The best part about it is that its a natural substance therefore I'm not putting more toxins in my body or having to take even more medications.