Iron supplements may be a simple remedy for the common dry cough associated with angiotensin converting enzyme (ACE) inhibitor drugs, a study has reported in Hypertension (August 2001;38:166), the journal of the American Heart Association. “Dry cough is the most often reported and troublesome complication associated with [the use of these drugs],” said one of the study's authors, Dr Kyung Pyo Hong, professor of medicine and chief of cardiology at Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. Although it was not serious, he added, it was the most common reason that people give for stopping taking the medicines.
Dr Hong and colleagues studied six men and 13 women, aged 60 years on average, who developed persistent cough while taking angiotensin converting enzyme inhibitors. Cough was defined as one that occurred during the use of this drug, subsided within seven days after its discontinuation, and reappeared 48 hours after its reintroduction.
Participants kept a diary during an initial two week observation while taking the drug, scoring the severity of their cough on a scale of 0 to 4 for two periods of 12 hours a day.
The participants then took, for four weeks, a daily morning tablet of 256 mg of ferrous sulphate or placebo. They documented their coughs during the treatment period and gave a blood sample at the end of the four weeks.
The average daily score for coughing in the group taking iron was 3.07 at the end of the observation period and 1.69 after four weeks of iron supplementation. No significant change in score was seen in the placebo group (2.57 before v 2.35 after treatment). Eight of the 10 subjects in the iron group showed improvement in their scores, whereas only 1 in 9 in the placebo group did so. Three patients in the iron group nearly stopped coughing completely.