Hi Sandy,
Do hope you are seeing success with alli and are well on the road to a healthier and slimmer you. With a little tweaking you can get the best benefits of this product and program.
There are no known interactions between ali and wellbutrin, so you need not change your wellbutrin's dosing schedule. Since alli does inhibit the absorbtion of fat it can block some of the absorption of the fat soluble vitamins (A,D,E,K) and other medications or supplements which are fat soluble (wellbutrin is water soluble).
Your bouts of constipation seem to be due to the runny stools from the day before. You may be evacuating the bowels one day and then building up the next. The fat content on your meals do have an effect. It is more of a challenge when eating on the road, but with practice it can be done. Many chain restaurants do have lighter choices and provide nutritional information. It is best to stay away from fried foods choosing grilled and asking for the dressing on the side.
As well as keeping yourself hydrated, you should also be getting in plenty of fiber, which not only helps in keeping you regulal but may reduce the runny days.
Hope this helps.
Sophia De Monte RPh