As highlighted in Chapter 10, adverse events are often overshadowed by emphasis of the positive treatment benefits in clinical trials. Details of reasons for withdrawals are frequently missing altogether in trial reports, and failure to perform an intention-to-treat analysis may compound this because dropouts may be related to lack of efficacy or to adverse events which are not obviously related to the trial medication.19 Rare side-effects are unlikely to show up in small clinical trials and often emerge as subsequent case reports or during post-marketing surveillance. Simply stating that no serious liver problems occurred in 100 patients taking traditional Chinese herbs for atopic eczema is still compatible with an upper 95% confidence limit of 3% if a larger population were tested.20
Particular efforts should therefore be made to scrutinise trials for a list of the frequency and severity of adverse events, as discussed in Chapter 10. As the events surrounding the thalidomide tragedy remind us, caution should be exercised when using new treatments that have not been tested on thousands of patients. Additional literature sources and postmarketing surveillance studies need to be scrutinised before one can reassure patients on side-effect issues within a reasonable degree of certainty.
Was this article helpful?