effect of brompheniramine on cough sensitivity in healthy volunteers

ABSTRACT

In evaluate the anti-tussive effect of brompheniramine maleate a non-selective, sedative antihistamine using capsaicin challenge. Twelve subjects, five females and seven females, mean age 32 years with a range of [23-39] years, were studied on two occasions. On the two visits a baseline capsaicin dose-response was performed to determine C5 [the Lowest concentration causing 5 coughs]. After 30 minutes two C5 doses of capstucin were given and the total cough over one minute was counted. On the first visit Brompheniramine 8mg or a matched placebo was given orally, and 120, 240 minutes alter administration, two C5 doses of capsaicin were given and the total coughs over one minute period were counted. This was repeated exactly in the second visit except subjects received either a placebo or active treatment; either which they had not received on their first visit. Subjects were also asked to quantify their drowsiness using a 100mm visual analogue scale. Baseline mean cough number [confidence interval] was similar on the two study occasions 9.9 [8.2-11.7] before Brompheniramine and 9.2 [7.3-11.1] before placebo. Cough number did not differ on the two study days at 120 and 240 min after Brompheniramine treatment 77 [55-98] 74 [5.1-96] compared to 87 [64-110] 83 [68-9.8] after placebo. Mean visual analogue scale [confidence interval] after Brompheniramine was 31 [14-48] and 40 [21-60] compared to 7[2-12] and 7 [2-12] after Placebo at 120 and 240 nun respectively [p<0.005]. The sedative anti histamine Bromphcniraniine did not affect capsaicin induced cough though it produced significant drowsiness