Lisinopril

In a study of 34 people with hypertension, six months of captopril or enalapril (ACE inhibitors related to lisinopril) treatment led to decreased zinc levels in certain white blood cells, raising concerns about possible ACE inhibitor–induced zinc depletion.

While zinc depletion has not been reported with lisinopril, until more is known, it makes sense for people taking lisinopril long term to consider, as a precaution, taking a zinc supplement or a multimineral tablet containing zinc. (Such multiminerals usually contain no more than 99 mg of potassium, probably not enough to trigger the above-mentioned interaction.) Supplements containing zinc should also contain copper, to protect against a zinc-induced copper deficiency.

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.

A potentially serious side effect of taking ACE inhibitors is increased blood potassium levels. This problem is more likely to occur in people with advanced kidney disease. Taking potassium supplements, potassium-containing salt substitutes (No Salt®, Morton Salt Substitute®, and others), or large amounts of high-potassium foods (including noni juice) at the same time as ACE inhibitors could cause life-threatening problems. Therefore, people should consult their healthcare practitioner before supplementing additional potassium and should have their blood levels of potassium checked periodically while taking ACE inhibitors.