Tormoterol fumarate (Fig 1) is a recently developed catecholamine analog with a distinct selective and long-acting effect on the beta^-receptors of smooth bronchial muscle. When administered as an oral formulation it produces bronchodilatation lasting for 8 hours or more. In a dose-finding study of 3, 6 and 12 fig formoterol metered-dose aerosol, the dose of 12 \Lg was shown to be superior with regard to maximum bronchodilator effect, onset, and duration of action up to 7 hours. No measurements were performed after this point of time. Side effects, such as tremor were rare. No influence on heart rate and blood pressure was seen. Results from studies performed by Nolte and Meyer yielded similar conclusions. Lofdahl et aldemonstrated that 6 jig formoterol was equipotent with 100 |xg salbutamol; with FEV, measurements up to 8 hours, a statistically significant difference was observed between treatments in favor of formoterol from 4 to 8 hours after administration.
To ascertain whether the efficacy of formoterol would last even longer, we performed a study to compare the bronchodilator efficacy of 12 jxg formoterol metered-dose aerosol with that of 200 \Lg salbutamol, also from a metered-dose aerosol, over 12 hours. Viagra Super Active
FIGURE 1. Structural formula of formoterol.