Enemas are a good idea as suggested, but a warm water enema should be enough, you do not have to do a Fleet enema. If you are going to do them regularly, I would suggest buying a stainless steel enema bucket to make your life easier.
I keep Renew Life Cleansemore on hand for occasional constipation. For me, one seems to be be too much so I`ll open a capsule and take half. It is horrid tasting but it works, and of course you can always just leave the capsules whole. It contains triphala and magnesium but no senna or cascara sagrada, the latter two can be habit forming.
In my most recent research, I have come across constipation as a symptom of hypothyroidism.