44% of candidates passed this question.

Candidates should have provided a definition of adverse drug reactions and then a classification. There are at least two widely accepted systems for classification, either was acceptable; though candidates often switched between both which led to a less structured answer. The WHO classification is comprehensive and logical, though both Rang and Dale and Goodman and Gilman also have sections on this topic.

Common errors were the citing of examples with the incorrect mechanism, describing only drug interactions rather than all adverse reactions and focussing the answer on the 4 hypersensitivity reactions which could only score a low mark. Some candidates confused drug errors with adverse reactions.