[Effect of SCH 1000 on bronchial hyperreactivity compared to that of fenoterol]

The hyperreactivity-modulating effect of SCH 1000 and fenoterol was tested in two groups of 10 patients. The drugs were administered at random, in simple blind fashion. Baseline pulmonary function was in the range of predicted values for all patients. One group received 80 micrograms of SCH 1000. When the drug was inhaled after carbachol challenge, pulmonary function returned to normal values in all patients. When the drug was inhaled before challenge, a shift to the right of the dose-effect curves was observed in all patients but 1. The other group received 800 micrograms of fenoterol. When the drug was administered after carbachol challenge, all 10 patients returned to baseline within 10 min. When it was given before carbachol challenge, a shift to the right of the dose-effect curves was observed in 9 patients out of 10. SCH 1000 and fenoterol induced an effective protection against carbachol, increasing the PD20 and shifting the dose-effect curves to the right in most of the asthmatics. In 2 patients, 80 micrograms of SCH 1000 or 800 micrograms of fenoterol seemed too low in order to achieve a complete protective effect.