These are the interactions listed on WebMD (looking at iboga):
"Drying medications (Anticholinergic drugs) interacts with IBOGA
Iboga contains chemicals that can affect the brain and heart. Some of these drying medications called anticholinergic drugs can also affect the brain and heart. But iboga works differently than drying medications. Iboga might decrease the effects of drying medications.
Some of these drying medications include atropine, scopolamine, and some medications used for allergies (antihistamines), and for depression (antidepressants).
Various medications used for glaucoma, Alzheimer's disease, and other conditions (Cholinergic drugs) interacts with IBOGA
Iboga contains a chemical that affects the body. This chemical is similar to some medications used for glaucoma, Alzheimer's disease, and other conditions. Taking iboga with these medications might increase the chance of side effects.
Some of these medications used for glaucoma, Alzheimer's disease, and other conditions include pilocarpine (Pilocar and others), donepezil (Aricept), tacrine (Cognex), and others."
I don't know if that means that these are just reported cases, or if these are the only interactions that would happen, but it was the only info I could easily find.