Adverse drug reactions: keeping up to date.

The amount of published literature on adverse drug reactions is overwhelming; for example, the serial publication Side Effects of Drugs Annual lists and critically discusses over 3000 references each year. As a group, pharmacotherapeutics journals publish more papers on adverse drug reactions than journals that cover other fields, but even so they publish a minority of the total number of papers, and no single journal or group of journals can be highlighted as being a frequent source of primary information. Non-specialists must therefore rely on secondary literature (reviews) and tertiary literature (critical summaries) for information. Most of the primary published literature is in the form of anecdotal reports (30%) and formal studies or randomized controlled trials (35%). The anecdotal reports vary in quality; a new serial publication devoted to this type of article would bring some of the literature together and would improve the quality of reporting. Although many of the randomized controlled trials are of good quality and large enough to reveal benefit, most are too small to provide robust information about adverse drug reactions. Systematic reviews are too few in number (only 1.25% of publications on adverse drug reactions cited in Side Effects of Drugs Annual); more are needed.