Does Ramipril cause mucus build up and coughing?

Ramipril can cause coughing. The evidence says about 7 in 100 people who take an ACE inhibitor get a cough, and ramipril's rate in one 2016 study was 6.89% [1].

That cough is usually dry and irritating, not mucus-producing. The 1989 review describes it as a "dry, nonproductive, persistent cough" with a tickling sensation in the throat [2]. A 1996 study found that people who coughed on this class of drug had much higher levels of a nerve irritant called substance P in their sputum (16.6 fmol/ml vs 0.9) [3], which fits the mechanism: ACE inhibitors block the breakdown of bradykinin and substance P, and those chemicals directly irritate the airway and stimulate the cough reflex [4, 2]. So if you are producing phlegm, it may be from something else, but the cough itself is a direct chemical effect.

The cough can start within a week of your first dose and sometimes takes several months to appear [1, 2]. Women are more likely to get it than men [1]. The fix that works, consistently and completely, is stopping the drug [2].

My call: ramipril causes a dry cough in roughly 1 of every 15 people who take it, through a direct mechanism involving bradykinin and substance P. The evidence shows no mechanism that would produce mucus from this drug. Confidence: high on the association and mechanism, moderate on the exact rate (it varies across studies and populations).