To compare the cost-effectiveness of oral bambuterol (B) (Bambec â, Astra) 20 mg once daily with that of salmeterol (S) (Serevent â, Glaxo Wellcome) pMDI 50 mg twice daily for treatment of asthma patients with nocturnal symptoms. METHODS: 126 patients, aged 18-70 years and using inhaled corticosteroids at a constant daily dose and with an FEV1 40-85% of predicted normal value, were included in this double-blind, randomized, parallel-group study (2 weeks' run-in and 6 weeks' treatment) in the UK, Italy and Norway. During run-in, they had to show a nocturnal awakening or early awakening due to asthma symptoms that required rescue medication at least once, and a ³ 15% fall in overnight PEF on 3 out of the last 7 days. Morning and evening PEF were measured and tremor was scored. The effectiveness variables in the cost-effectiveness analysis were symptom-free days and number of nights with no awakenings. Costs for both study and rescue medication were calculated. RESULTS: There were no statistically significant differences between B and S regarding morning and evening PEF (change from baseline), tremor and the effectiveness variables. Mean number of symptom-free days were 20-25% and mean number of nights with no awakenings was 69-77%. Costs (study + rescue medication) were lower during bambuterol treatment in all three countries. UK Italy Norway Daily cost Bamb Salm Bamb Salm Bamb Salm US $ 0.71 1.35 0.67 0.92 0.74 1.19 CONCLUSION: Treatment with bambuterol is more cost-effective than treatment with salmeterol in asthma patients with nocturnal symptoms.