Prevention of Exacerbations of Chronic Obstructive Pulmonary Disease with Tiotropium

IN RESPONSE:

The authors of both letters express concerns related to the discontinuation of ipratropium therapy in many participants. They view ipratropium as a standard of care in the community and therefore conclude that withdrawing the drug makes the trial both clinically irrelevant and unethical. We will briefly review the scientific basis for their claims.

Two large trials compared the bronchodilator effects of ipratropium, albuterol, and both drugs used in combination (1, 2). Both trials clearly demonstrated that ipratropium is an effective bronchodilator in COPD, but albuterol produces almost identical responses. Combined treatment produces better bronchodilation than either drug alone, but the additive effect is small and is not associated with overall differences in symptom scores among the 3 treatment groups. These results indicate that albuterol and ipratropium can be used interchangeably for short-term …