Inhaled sodium cromoglycate in angiotensin-converting enzyme inhibitor cough

Cough is a frequent side-effect of angiotensin-converting enzyme (ACE) inhibitors. We examined the effects of inhaled sodium cromoglycate in 10 patients with ACE-inhibitor cough in a double-blind crossover study. After a 2-week run-in, patients were randomised to either 2 weeksʹ inhaled sodium cromoglycate or placebo followed by a further 2 weeks on the other treatment. Patients kept a cough diary during each study period. Cough severity was recorded on a scale from 0 to 12. At the end of each study period the cough threshold to inhaled capsaicin was measured. 9 patients reported a reduction in cough after sodium cromoglycate. Median (range) daily cough scores during run-in and placebo periods were 3·6 (1·9-6·4) and 4·1 (0·6-8·1), respectively (p>0·05). Median daily cough score after sodium cromoglycate was 1·8 (0·4-3; p<0·01). There was a significant relation between initial cough severity and benefit from sodium cromoglycate; and cough- reflex sensitivity to inhaled capsaicin was significantly reduced. Inhaled sodium cromoglycate is an effective treatment for ACE-inhibitor cough. Its effect may be due to suppression of afferent vagal activity.