Aug. 16, 2001 -- As many as one-third of the people who take widely prescribed cardiovascular drugs called ACE inhibitors develop a dry, hacking cough that is so bothersome they often stop taking the drugs. Well, breathe a sigh of relieve. There may be an ironclad cure for this "ACE cough": iron supplements.
If this cough remedy can stand up to scientific scrutiny, it will prove to be a major breakthrough, says Lynn Smaha, MD, PhD, a spokesman for the American Heart Association.
"From a clinical point of view, ACE inhibitors play a significant role in improving longevity and reducing [sickness and death]," says Smaha, the executive vice president of Guthrie Clinic in Sayre, Penn. "But ACE inhibitors are frustrating because frequently the patient will not tolerate the drug because of the cough."
ACE inhibitors, such as Capoten, Ramipril, Vasotec, and Lotensin, are recommended for people with heart failure and are the drug of choice for treating high blood pressure in people with diabetes. In some studies, the drugs also are associated with a lower risk for heart attack or stroke.
But Smaha says it is too soon to start sending people who take ACE inhibitors down to the corner drug store for iron supplements. The new research, reported in the August issue of Hypertension: Journal of the American Heart Association, is just "too preliminary" for everyone to jump on the iron bandwagon, says Smaha.
In the study, heart researcher Kyung Pyo Hong, MD, and colleagues from the Samsung Medical Center of Sungkyunkwan University School of Medicine in Seoul, Korea, studied 19 people who had developed cough after taking ACE inhibitors. The volunteers received either iron supplements or dummy pills for four weeks.
Those taking the iron supplement coughed far less than they had before, while patients taking dummy pills had no significant change in the amount of coughing.
The iron dose these people took is "high but not a mega dose," says Smaha. Hong tells WebMD that patients were given 256 mg of ferrous sulfate, which contains 80 mg of iron. "The daily requirement of iron is less than 20 mg in a healthy adult," says Hong.
Although the patients in the study were taking a variety of ACE inhibitors, Hong says the numbers were "too small to compare the effect of iron on different ACE inhibitors."
Hong says that although no study has explained the exact mechanism of the ACE-inhibitor cough, many experts think it is related to a natural compound called nitric oxide. ACE inhibitors cause the body to increase nitric oxide production, and nitric oxide is known to irritate the lungs and possibly cause coughing. Iron interferes with production of nitric oxide.
Although Smaha isn't recommending the iron supplements for cough, he expects some people will ignore the cautions of medical experts and just try iron on their own. For those so inclined, Smaha warns that not all people can tolerate iron supplements. "Some patients have allergies to substances in the iron pills, and in some patients iron supplementation can cause GI side effects," such as constipation and stomach upset, he says.