Mestinon gives me diarrhea so I was taking Immodium usually once a day - that seems to cause constipation. Have any of you learned any tricks to deal with this?

Anything that could constipate you might work. I have used a daily banana. Also I saw something about An old antidepressant that starts with A to counter side effects like that. Different things constipate different folks. Cheese affects my grandson that way. Sculptor44

Try taking a light snack with your mestinon, for example a small pancake even 1/2 pancake, may help with reducing the diarrhea issues.

If you have lactose intolerance, that could be the problem, at least in part. The mestinon pills use lactose as the filler (the stuff they mix the actual medicine with to be able to pack the pills into shape.)

I found that using a lactase pill (over the counter, like Lact-Aid or Dairy-Ease) with each dose of mestinon helped tremendously. Worked it down to using just 1/2, then 1/4, of the lactase tablet, which seemed to be enough for me.

Taking it with some food also seems to help, as suggested above. something to temper the effect of the pill on empty stomach and guts.

Why the manufacturers use lactose in pills, knowing so many people have trouble with it, is beyond me.