RESUMO
A double-blind, cross over, placebo controlled study was conducted to compare the response of lung function to metered doses inhaler of ipratropium bromide (IB, 40 micrograms, fenoterol hydrobromide (F), 100 micrograms, and a combination of the two (IBF). The drugs were administered on 4 consecutive days to 16 stable chronic airway obstructive patients (COPD), all of whom had shown minimal improvement after inhaling sympathomimetic drugs. Lung function response was measured for six hours after administration. All active medications caused greater improvement of FEV1 and FVC than the placebo did and none caused cardiovascular side effects. Improvement of FEV1 and FVC after IBF therapy was significantly better than after F at 1 hour and lasted up to six hour, whereas IBF was better than IB only after the third hour onwards. In addition, additive effects on FEV1 and FVC were seen in this period. IB caused greater response in FEV1 and FVC than F at both first and fifth hour. IB and IBF showed a rapid onset of action and had greater duration of action than F.