I used to suffer a lot from heartburn and indigestion. Really, a good chunk of my life since maybe 14 years old. I'm in my mid 40s now. Though I can't be sure if any medications exacerbated it along the way, I can say I had it more before taking any kind of medication than when I was (have been) on medications. I think one of the main causes for my gastrointestinal distress has been stress. I noticed it more when elevated in mood than not.

Knock on wood, I've had relatively little heartburn and indigestion in recent years. Only on rare occasions, while earlier in my life it almost seemed constant. My husband used to make fun of how many Tums I used to take. Nowadays I prefer Alka Seltzer fruit chewables. They are much more pleasant than Tums. When it's bad, I take a Nexium.

Do talk to your doctors (not just your psychiatrist, but your GP) about these issues. Also be sure that any OTC relief aids are OK with all of your medications. I may be remembering wrong, but I think I was told to avoid certain antacids when I took Lithium.