I don't recall having constipation because of an AP, including Trilafon, but had horrible constipation on the drug Cogentin (benztropine sp?) Cogentin was for easing my past akathisia. I had to stop Cogentin for that reason.

I don't have major issues with constipation, usually, but when I do, and it's not because of a medication, it's usually because of stress. Travel is a big trigger for it, especially international travel. It's likely because my "routine" gets disrupted, too. Routine is so important for my "regularity".