ONSET AND DURATION OF ACTION OF SINGLE DOSES OF FORMOTEROL INHALED VIA TURBUHALER(R)

The aim of the study was to investigate the time of onset and the dura tion of the bronchodilating effect of different doses of formoterol ad ministered via Tulbuhaler(R) in patients with moderate asthma. Thirty- one patients (five women) with a mean forced expiratory volume in s (F EV1) of 1.97 +/- 0.541 and a mean reversibility of 31 +/- 14% of basel ine were included in this double-blind. randomized. placebo-controlled and cross-over study. The patients inhaled single doses of placebo, i .e. 6, 12, 24, or 48 mu g formoterol fumarate, on 5 separate days. Ser ial measurements of specific airways conductance (SGaw) and FEV1 were performed at regular time intervals for 12 h. The majority of the pati ents had at least a 50% increase in SGAW within 1-4 min after administ ration of all active treatments. The maximum increase in FEV1 over pla cebo was dose-dependent: 12% (6 mu g), 18% (12 mu g), 19% (24 mu g), a nd 26% (48 mu g) (P<0.001). Twelve hours after administration of 6. 12 , 24, and 48 mu g formoterol, the mean increase in FEV1 was still 7%, 15%, 18% and 27%, respectively, above the value following placebo. Hea dache was the most frequently reported adverse event in all treatments including placebo. After inhalation of 48 mu g, three patients experi enced mild tremor lasting for less than 1 h; likewise, one patient exp erienced the same event for 3 h after placebo. Formoterol administered via Turbuhaler(R) gave a rapid and dose-related bronchodilating effec t lasting for 12 h and was well tolerated.