Claims in advertisements for anti hypertensive drugs in a Dutch medical journal

Background Advertising claims must not conflict with the official summary of product characteristics. After a drug has been approved, new clinical evidence may become available.

Aims To determine how the pharmaceutical industry deals with evolving clinical evidence in advertising claims for anti hypertensive drugs, and whether such pharmaceutical promotion is up to standard.

Methods We examined all advertisements from the Dutch Journal of Medicine published between 1996 and 2004. We judged whether claims were in agreement with the information available from the summary of product characteristics or evidence from cited clinical trials. Subsequently, we reviewed whether these claims had been assessed by the Code of Practice authority.

Results We identified 50 unique advertisements with, in total, 492 appearances for 16 antihypertensive drugs. Claims of blood pressure lowering and convenient use were all judged to be sufficiently substantiated. For calcium-channel blockers, insufficiently supported safety claims had been made in three cases (41 appearances). Claims suggesting effects on long-term outcomes started in 1999 for angiotensin II receptor blockers, and were made during the whole period for several other anti hypertensive drugs. In 16 cases (135 appearances), such claims were not supported by the available information. Some claims were premature, others transferred results from a specific patient group to the general population of hypertensive patients. Only two cases were reviewed by the Code of Practice authority.

Conclusions Overall, 35% of the advertisements for anti hypertensive drugs contained suggestive claims not supported by the offered evidence. The current system of self-regulation cannot ensure that pharmaceutical promotion is always accurate, balanced and evidence-based.