Cumulative dose-response study comparing terbutaline pressurized aerosol administered via a pearshaped spacer and terbutaline in a nebulized solution

Summary The bronchodilator effects of cumulative doses of terbutaline 0.125 mg, 0.125 mg and 0.250 mg administered as a pressurized aerosol via a pearshaped spacer were compared with those of terbutaline 1.25 mg, 1.25 mg and 2.50 mg administered as a nebulized solution via a PARI-inhaler Boy. FEV_1.0 and flow-volume curves in 13 patients were measured. Initial placebo treatment of both groups resulted in a significant increase in FEV_1.0, especially when it was given in nebulized form. The increase after active drug was significant after 15 min, with only minor changes during the rest of the trial. The log-dose/increase in FEV_1.0 showed that equipotent doses of pressurized and nebulized terbutaline were in the ratio 1 to 4. Administration by nebulization offered no clear advantage over use of a pressurized aerosol with a pearshaped spacer.