BACKGROUND A study was undertaken to evaluate and compare the efficacy and safety of tiotropium and ipratropium during long term treatment in patients with stable chronic obstructive pulmonary disease (COPD).

RESULTS During treatment tiotropium achieved a significantly greater improvement than ipratropium (p<0.05) in trough, average, and peak FEV₁levels and in trough and average FVC levels. The trough FEV₁ response on days 8, 50, and 92 ranged between 0.15 l (95% CI 0.11 to 0.19) and 0.16 l (95% CI 0.12 to 0.20) for tiotropium and between 0.01 l (95% CI –0.03 to 0.05) and 0.03 l (95% CI 0.01 to 0.07) for ipratropium. The trough FVC response on days 8, 50, and 92 ranged between 0.34 l (95% CI 0.28 to 0.40) and 0.39 l (95% CI 0.31 to 0.47) for tiotropium and between 0.08 l (95% CI 0.00 to 0.16) and 0.18 l (95% CI 0.08 to 0.28) for ipratropium. On all test days tiotropium produced a greater improvement in FEV₁than ipratropium starting three hours after inhalation (p<0.05). During treatment weekly mean morning and evening peak expiratory flow (PEF) was consistently better in the tiotropium group than in the ipratropium group, the difference in morning PEF being significant up through week 10 and in evening PEF up through week 7 of treatment (p<0.05). The use of concomitant salbutamol was also lower in the tiotropium group (p<0.05). The only drug related adverse event was dry mouth (tiotropium 14.7%, ipratropium 10.3% of patients).

CONCLUSIONS Tiotropium in a dose of 18 μg inhaled once daily using the HandiHaler was significantly more effective than 40 μg ipratropium four times daily in improving trough, average, and peak lung function over the 13 week period. The safety profile of tiotropium was similar to ipratropium. These data support the use of tiotropium as first line treatment for the long term maintenance treatment of patients with airflow obstruction due to COPD.