The manufacturer, Boehringer Ingelheim, recently informed the FDA that ongoing safety monitoring had identified a possible increased risk of stroke in patients who take this medicine. In a pooled analysis of safety data from 29 placebo controlled trials (including 13,500 patients with COPD), the preliminary estimates of the risk of stroke were 8 patients per 1000 patients treated for one year with tiotropium, and 6 patients per 1000 patients treated for one year with placebo. This suggests an extra 2 patients in every 1000 treated with tiotropium for one year would experience a stroke, who would not have done had they taken placebo (relative risk =1.33, number needed to harm [NNH] = 500).
It is important to interpret these preliminary results with caution. The FDA points out that it has not confirmed these analyses, which have inherent limitations and uncertainty that require further investigation using other data sources. The FDA is working with Boehringer Ingelheim to further evaluate the potential association between tiotropium and stroke. Results from a large, four year study, UPLIFT (Understanding the Potential Long-Term Impacts on Function with Tiotropium), which will be available in June 2008, will provide additional insight into the risk of stroke or other safety findings with tiotropium.
Healthcare professionals should be aware of this possible safety concern, and report suspected adverse drug reactions with tiotropium to the Medicines and Healthcare products Regulatory Agency (MHRA) through the Yellow Card Scheme.