exerciseinduced asthma in children and oral terbutaline a doseresponse relationship study we wanted to assess the protective effects on exerciseinduced asthma as well as the clinical efficacy and safety of increasing doses of a new sustainedrelease formulation of terbutaline sulphate in 17 asthmatic children aged 612 years mean 9 years placebo 2 4 and 6 mg terbutaline were given bid for 14 days in a randomized doubleblind crossover design at the end of each two week period an exercise test was performed and plasma terbutaline was measured compared with placebo no significant effect was seen on asthma symptoms monitored at home or on exerciseinduced asthma the percentage falls in fev1 after the exercise test were 36 35 27 and 28 after placebo 4 8 and 12 mg terbutalineday respectively a small but statistically significant doserelated increase was seen in morning and evening peak expiratory flow pef recordings it is concluded that continuous treatment even with high doses or oral terbutaline does not offer clinically useful protection against exerciseinduced asthma