EDITOR,—Anton J M de Craen and colleagues address the question of the added analgesic effect and safety of codeine combined with paracetamol through a literature review with meta-analysis and an assessment of the methodological quality of the published trials.1 Their paper is a long overdue contribution to evidence based pharmacotherapy. Their recommendations to improve the quality of clinical trials, however, deserve attention.

The authors criticise several of the papers for not using the intention to treat approach. The justification for …