Several side effects may develop with the use of captopril. A cough that does not go away is one of the most commonly reported problems. Captopril works by blocking the angiotensin-converting enzyme, which may cause a buildup of substances in the lung and lead to a chronic cough. This captopril cough can appear within hours after taking the first dose or months later.
There are a number of possible side effects that can occur with captopril (available as Capoten® and generic captopril). One side effect that is common in captopril, as with all ACE inhibitors, is a persistent dry cough.
Captopril is part of a class of drugs called angiotensin-converting enzyme inhibitors, or ACE inhibitors for short. Captopril helps to block the angiotensin-converting enzyme, which is normally part of a reaction in the body that causes blood vessels to narrow (constrict). By blocking this enzyme, captopril causes blood vessels to relax, which lowers blood pressure and helps with symptoms of congestive heart failure.
However, scientists also believe that angiotensin-converting enzyme is responsible for the breakdown of other substances in the lungs. When ACE is blocked, these substances can build up in the lungs, which can ultimately lead to a chronic cough.
The likelihood of developing a cough while taking an ACE inhibitor appears to be affected by a number of factors, including the specific ACE inhibitor and a person's genetics. Some ACE inhibitors can cause a cough in up to 35 percent of people taking the medicine.
Based on data from clinical studies, up to 2 percent of people with high blood pressure and up to 4 percent of people with congestive heart failure who were taking captopril reported a cough.
For people taking captopril, a cough can first appear within hours after taking the first dose or months after the medicine is first taken. Unfortunately, there is no way to know if or when a cough will occur. Once captopril is stopped, the cough also stops, though the amount of time for this can also vary. On average, it can take up to 14 days for the cough to completely go away. In some studies, however, it has been reported to take months.