Angiotensin-Converting Enzyme (ACE) Inhibitors

Angiotensin-converting enzyme (ACE) inhibitors constitute a family of drugs used to treat high blood pressure and heart failure, as well as to improve survival following a heart attack. ACE inhibitors are also used to slow the progression of kidney disease in people with diabetes.

Interactions that are common to all ACE inhibitors are described below. For interactions involving specific ACE inhibitors, refer to the highlighted drugs listed below.

Summary of Interactions with Vitamins, Herbs, and Foods
(for details about the summarized interactions, read the full article)

May be Beneficial: Side effect reduction/prevention—Taking these supplements may help reduce the likelihood and/or severity of a potential side effect caused by the medication.	Iron
Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.	High-potassium foods Potassium supplements Salt substitutes
Depletion or interference	None known
Supportive interaction	None known
Reduced drug absorption/bioavailability	None known
Interactions common to many, if not all, ACE Inhibitors are described in this article. Interactions reported for only one or several drugs in this class may not be listed in this article. Some drugs listed in this article are linked to articles specific to that respective drug; please refer to those individual drug articles. The information in this article may not necessarily apply to drugs in this class for which no separate article exists. If you are taking an ACE Inhibitor for which no separate article exists, talk with your doctor or pharmacist.

Interactions with Dietary Supplements

Potassium
An uncommon yet potentially serious side effect of taking ACE inhibitors is increased blood potassium levels.¹ ² ³ Taking potassium supplements,⁴ potassium-containing salt substitutes (No Salt®, Morton Salt Substitute®, and others),⁵ ⁶ ⁷ or large amounts of high-potassium foods at the same time as ACE inhibitors could cause life-threatening problems.⁸ Therefore, individuals should consult their healthcare practitioner before supplementing additional potassium and should have their blood levels of potassium checked periodically while taking ACE inhibitors.

Iron
In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor, supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks reduced the severity of the cough by a statistically significant 45%, compared with a nonsignificant 8% improvement in the placebo group.⁹

References

1. Good CB, McDermott L, McCloskey B. Diet and serum potassium in patients on ACE inhibitors. JAMA 1995;274:538.

2. Rush JE, Merrill DD. The Safety and tolerability of lisinopril in clinical trials. J Cardiovasc Pharmacol 1987;9(Suppl 3):S99–107.

3. Sifton DW, ed. Physicians’ Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 1965–8.

4. Burnakis TG, Mioduch HJ. Combined therapy with captopril and potassium supplementation. A potential for hyperkalemia. Arch Intern Med 1984;144:2371–2.

5. Burnakis TG. Captopril and increased serum potassium levels. JAMA 1984;252:1682–3 [letter].

6. Ray K, Dorman S, Watson R. Severe hyperkalemia due to the concomitant use of salt substitutes and ACE inhibitors in hypertension: a potentially life threatening interaction. J Hum Hypertens 1999;13:717–20.

7. Sifton DW, ed. Physicians’ Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 1965–8.

8. Stoltz ML. Severe hyperkalemia during very-low-calorie diets and angiotensin converting enzyme use. JAMA 1990;264:2737–8 [letter].

9. Lee SC, Park SW, Kim DK, et al. Iron supplementation inhibits cough associated with ACE inhibitors. Hypertension 2001;38:166–70.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires July 2004.