Respimat (R) (a new soft mist inhaler) delivering fenoterol plus ipratropium bromide provides equivalent bronchodilation at half the cumulative dose compared with a conventional metered dose inhaler in asthmatic patients

Background: Respimat(R), a possible alternative to the conventional metered dose inhaler (MDI), is a novel, reusable, propellant-free, multidose soft mist inhaler. Respimat slowly releases a metered dose of active substance a s a soft mist with a high proportion of the dose in the fine particle fract ion, leading to improved lung deposition following inhalation when compared with the conventional MDI. Objectives and Methods: The equipotent bronchod ilating efficacy and safety of a combination of fenoterol hydrobromide and ipratropium bromide (F/I) in cumulative doses delivered by either Respimat or pressurised MDI was assessed in a randomised, controlled, double-blind ( within device) 4-way crossover study. Forty-three patients with stable asth ma (mean FEV1 62% predicted) responsive to F/I inhaled cumulatively 16 puff s on each of 4 test days (1 + 1 + 2 + 4 + 8 puffs at 50-min intervals) via Respimat delivering 50/20, 25/20 or 25/10 mu g F/I per puff or via MDI deli vering 50/20 mu g WI per puff. Results: Cumulative doses of 400/160 and 400 /320 mu g F/I via Respimat produced bronchodilation (evaluated by average i ncrease in FEV1 45-245 min after first inhalation) equivalent to that achie ved with a cumulative 800/320 mu g F/I via MDI (mean increase in FEV1 above baseline 0.76, 0.73 and 0.71 litres, respectively). The tolerability of th e F/I combination via Respimat was also comparable to that of twice the dos e delivered via MDI. Conclusion: Therefore, a fenoterol hydrobromide/ipratr opium bromide combination delivered by Respimat is as safe and effective as the MDI at half the cumulative dose, on acute administration to patients w ith asthma. Copyright (C) 2000 S. Karger AG, Basel.