Quick answer

Ask your pharmacist or doctor before combining. NIH says potassium iodide taken with ACE inhibitors such as lisinopril could raise blood potassium to an unsafe level. The prescription potassium iodide label lists the same interaction and names high potassium and serious heart rhythm effects. Neither source gives a cutoff amount.^1,2

Key facts

NIH's consumer sheet says potassium iodide taken with ACE inhibitors could raise blood potassium to an unsafe level.¹
NIH's professional sheet says the combination can increase the risk of hyperkalemia, which is blood potassium that is too high.³
The prescription potassium iodide solution label says use with ACE inhibitors may result in hyperkalemia and cardiac arrhythmias or cardiac arrest.²
NIH names potassium iodide, one of the usual supplement forms of iodine. The passages do not name sodium iodide or kelp.^1,3
The lisinopril label lists potassium supplements and potassium-containing salt substitutes among the factors that raise the risk of high potassium.⁴

Ask your pharmacist or doctor first

Potassium iodide taken with ACE inhibitors such as lisinopril can raise blood potassium to an unsafe level. NIH and the potassium iodide label both list this interaction.^1,2,3

On the medicine's label

Does iodine interact with ACE inhibitors?

MedlinePlus describes lisinopril, an ACE inhibitor, as a medicine for high blood pressure and heart failure. NIH's iodine fact sheet for consumers says that taking potassium iodide with medicines for high blood pressure known as ACE inhibitors could raise the amount of potassium in your blood to an unsafe level. Its health professional sheet says the combination can increase the risk of hyperkalemia.^1,3,5

The prescription potassium iodide label says use with ACE inhibitors may result in hyperkalemia and cardiac arrhythmias or cardiac arrest. That label is for a saturated solution sold as an expectorant, a different product from a dietary supplement.²

Is it the iodine or the potassium?

Hyperkalemia means too much potassium in the blood, so the concern in these sources is the potassium that comes with potassium iodide. ACE inhibitors reduce the potassium lost in urine, and NIH says experts recommend monitoring potassium in people who take them, especially with kidney problems or other risk factors. The lisinopril label lists potassium-sparing diuretics, potassium supplements and potassium-containing salt substitutes among the factors that raise the risk.^4,6

Too much potassium in the blood (hyperkalemia) can cause muscle weakness, paralysis, heart palpitations, a burning or prickling feeling in the hands and feet, and irregular heart rhythms that can be life threatening. It can also cause no symptoms until it is severe.⁶

How much potassium is in an iodine supplement?

NIH's potassium sheet says potassium iodide on a label is there as a source of iodine, in microgram amounts, not as a source of potassium. The prescription potassium iodide solution is a different product, with label doses in the hundreds of milligrams. NIH and the label name the combination with ACE inhibitors without giving an amount below which it stops mattering, so whether your product is a concern is a question for your pharmacist.^2,6

Which iodine products contain potassium iodide?

NIH says iodine in supplements is usually potassium iodide or sodium iodide, that many multivitamin and mineral supplements contain iodine, and that kelp supplements are another source. In one analysis, 74% of 89 best-selling US adult multivitamins contained iodine, all as potassium iodide. The NIH passages on ACE inhibitors name potassium iodide. The sources checked do not say whether sodium iodide or kelp behaves the same way, which is not a finding either way.^1,7

Does the same apply to other medicines that keep potassium?

Ask your pharmacist or doctor first

Potassium iodide taken with potassium-sparing diuretics such as spironolactone or amiloride can raise blood potassium too high. NIH and the potassium iodide label both list this interaction.^1,2,3

On the medicine's label

The NIH iodine sheets and the label name ACE inhibitors and potassium-sparing diuretics. They do not address angiotensin receptor blockers, a related kind of blood pressure medicine. That is not a finding either way, so ask your pharmacist if you take one.^3,6

What to ask your pharmacist about iodine and your blood pressure medicine

Does my iodine supplement, multivitamin or kelp product contain potassium iodide?
Do I also use a potassium salt substitute or take a potassium supplement?⁴
When was my potassium last checked, and do I have kidney problems?
Is my blood pressure medicine an ACE inhibitor, an angiotensin receptor blocker or a water pill?

Questions people ask

Does iodine interact with ACE inhibitors?

NIH and the prescription potassium iodide label say potassium iodide taken with ACE inhibitors can raise blood potassium. Neither gives a cutoff amount, so ask your pharmacist about your own product.^2,3

Does iodine interact with any medications?

NIH names antithyroid medicines, ACE inhibitors and potassium-sparing diuretics, and the potassium iodide label also lists lithium.^1,2

What interacts with ACE inhibitors?

The lisinopril label lists potassium-sparing diuretics, potassium supplements and potassium-containing salt substitutes among the factors that raise the risk of high potassium, along with kidney problems and diabetes. Ask your pharmacist about everything you take.⁴

Is the iodine in a multivitamin a concern with an ACE inhibitor?

The sources do not say. NIH names potassium iodide, and many multivitamins contain it, so show your pharmacist the Supplement Facts panel.¹

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Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.