Chest has published a analysis of several tiotropium (Spiriva®). The analysis examined various adverse event end points and compared the reported rates in the active and placebo arms of the included studies.
The analysis examined data for 4,435 tiotropium patients and 3,384 placebo patients. Statistical differences were identified for several reported adverse events, namely dyspnoea, exacerbation of COPD, urinary retention and dry mouth.
Comparing those patients who received tiotropium with those who received placebo:
- Dry mouth was more likely, Relative Risk of 3.60 [95% CI, 2.56 to 5.05]
- Urinary retention was more likely, Relative Risk of 10.93 [95% CI, 1.26 to 94.88]
- Dyspnoea was less likely, Relative Risk of 0.64 [95% CI, 0.50 to 0.81]
- Exacerbation of COPD was less likely, Relative Risk of 0.72 [95% CI, 0.64 to 0.82]
Mortality was not different between the two groups when analysed by cardiovascular, respiratory and all causes.
This analysis concludes that this pooled analysis "supports the present safety profile of tiotropium". It would appear that dyspnoea can be relieved and exacerbations made less likely at the risk of an increased likelihood of dry mouth and urinary retention. It should be noted that this analysis is only in comparison to placebo and not other active treatments. It remains unclear how tiotropium compares to ipratropium over long periods in terms of reducing hospital admissions and deaths from respiratory causes.
Action: This study adds to the safety data available for tiotropium but long-term efficacy data relating to hospital admissions and respiratory deaths are still needed.