Antacids (Tums, Maalox, Mylanta) and Rifampin interaction
Antacids (Tums, Maalox, Mylanta) and Rifampin: the Rifampin prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Rifampin (Rifadin IV) label · effective 2026-05-27
Quinine Prevention or Management: Avoid concomitant use Decrease AUC by 75%–85% Telithromycin Decrease AUC by 86% Theophylline Decrease exposure by 20% to 40% Effect of Other Drugs on Rifampin Concomitant antacid administration may reduce the absorption of rifampin.
Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.