A dose response study comparing Duovent vs salbutamol

The dose response profiles of Duovent (fenoterol 0.1 mg/ipratropium 0.04 mg per puff) and salbutamol (0.1 mg per puff) were determined in a double-blind, controlled study. Twenty-one patients with asthma and nine patients with chronic bronchitis received 1, 2, 4, and 6 puffs of either Duovent or salbutamol on separate days. FEV1, pulse and tremor were recorded at baseline and up to 360 minutes after inhalation of test medication. Duovent and salbutamol produced an effective bronchodilator response at all dose levels, however, at 2, 4 and 6 puffs, the improvement with Duovent was significantly greater than with salbutamol alone in both asthmatic and chronic bronchitic patients. Two puffs of Duovent produced a significantly greater bronchodilation than all doses of salbutamol. There was no difference in the bronchodilator response between 1-6 puffs of salbutamol indicating maximal dose was achieved with one puff. There was an incremental improvement in FEV1 with 1, 2, and 4 puffs of Duovent but no difference between 4 and 6 puffs. There was no difference in pulse rate or tremor between salbutamol or Duovent at any dose level. We conclude that Duovent produces a greater and more prolonged bronchodilator response than salbutamol in both asthmatic and chronic bronchitic patients.