Captopril and Potassium interaction
Captopril and Potassium: the Captopril 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
Curated guidance for Potassium
These medicines reduce potassium excretion; adding potassium supplements or salt substitutes can cause hyperkalemia, which affects heart rhythm.
From the Captopril label · effective 2026-02-06
Potassium-sparing diuretics such as spironolactone, triamterene, or amiloride, or potassium supplements should be given only for documented hypokalemia, and then with caution, since they may lead to a significant increase of serum potassium.
Salt substitutes containing potassium should also be used with caution.
Patients should be advised not to use potassium-sparing diuretics, potassium supplements or potassium-containing salt substitutes without consulting their physician.
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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.