Respimat (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, 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 as a soft mist with a high proportion of the dose in the fine particle fraction, leading to improved lung deposition following inhalation when compared with the conventional MDI.

OBJECTIVES AND METHODS

The equipotent bronchodilating 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 asthma (mean FEV(1) 62% predicted) responsive to F/I inhaled cumulatively 16 puffs 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 microg F/I per puff or via MDI delivering 50/20 microg F/I per puff.

RESULTS

Cumulative doses of 400/160 and 400/320 microg F/I via Respimat produced bronchodilation (evaluated by average increase in FEV(1) 45-245 min after first inhalation) equivalent to that achieved with a cumulative 800/320 microg F/I via MDI (mean increase in FEV(1) above baseline 0.76, 0.73 and 0.71 litres, respectively). The tolerability of the F/I combination via Respimat was also comparable to that of twice the dose delivered via MDI.

CONCLUSION

Therefore, a fenoterol hydrobromide/ipratropium bromide combination delivered by Respimat is as safe and effective as the MDI at half the cumulative dose, on acute administration to patients with asthma.