Is it fine to take antacids or indigestion remedies at the same time as stimulant medication?

It depends on which stimulant and which indigestion remedy you mean. They aren't universally safe to take together. • Amphetamine stimulants (such as Adderall, lisdexamfetamine): antacids that raise stomach pH, particularly alkaline products containing sodium bicarbonate or calcium carbonate, can increase amphetamine absorption/exposure and is a specific contra indication. • Acid-reducing medicines such as PPIs (omeprazole, etc.) and H2 blockers can also affect drugs whose absorption depends on stomach acidity, so the specific stimulant matters. • Methylphenidate (Ritalin, Concerta, etc.) has different interaction considerations, so the answer isn't the same as for amphetamines. So I wouldn't assume that taking an antacid at exactly the same time is fine without knowing the medications.