Evaluation of different doses of formoterol from a newly developed powder inhalation device in asthmatic patients.

Administration of different doses of formoterol from a recently developed multiple dose dry powder device was tested in a placebo-controlled, single-centre, double-blind, within-patient trial. Eighteen patients of both sexes, aged 18-65 years, with a FEV1 of 50-80% and a reversibility of at least 15% were randomized. During four treatment periods of 8 days each, divided by approximately 6 days, patients received placebo or 6, 12 or 24 micrograms (PL, F6, F12 and F24, respectively) of formoterol from the powder device. Efficacy parameters (FEV1) and safety parameters (primarily pulse rate, electrocardiogram [ECG] and subjective experiences) were evaluated during 24 hours on the last day of each treatment period. Peak flow and the number of puffs of used rescue medication (100 micrograms of salbutamol) were registered during treatment periods. For efficacy analysis, 17 patients remained. For FEV1 0.5 hour before the last dose and 12 and 24 hours after the last dose all formoterol doses were statistically significant superior to placebo. Clinically relevant differences from placebo were found up to 8 hours (F6) and 12 hours (F12 and F24). The difference between doses was clinically relevant for the area under the FEV1 curve between F6 and F24. PEF on the treatment days corresponded to these findings. In three cases of 13 reported adverse effects, the relation to trial medication was probable (tremor) or possible (insomnia and hyperaesthesia). All other safety measurements showed no significant differences. We conclude that formoterol dry powder in the newly developed multiple dose inhalation device is an effective and safe beta 2-stimulant with a long duration of action in doses of 6, 12 and 24 micrograms. The 24 micrograms dose is superior to the 6 micrograms dose. Efficacy decreased considerably between the 12th and 24th hour after dosing.