Guidelines, polypharmacy, and drug-drug interactions in patients with multimorbidity

Polypharmacy, defined as the chronic co-prescription of several drugs, is often the consequence of the application of disease specific guidelines, targeting disease specific goals, to patients with multiple chronic diseases. One common consequence of polypharmacy is the high rate of adverse drug reactions, mainly from drug-drug interactions (the ability of a drug to modify the action or effect of another drug administered successively or simultaneously).1 The risk of a drug-drug interaction in any particular patient increases with the number of co-existing diseases and the number of drugs prescribed.2

In a linked paper, Dumbreck and colleagues (doi:10.1136/bmj.h949) selected three clinical guidelines produced by the National Institute for Health and Care Excellence (NICE)—type 2 diabetes, heart failure, and depression—and systematically looked for possible drug-disease and drug-drug interactions in relation to another 11 NICE guidelines for potentially comorbid chronic conditions.3 Drug-disease interactions were relatively uncommon and mostly occurred between the recommended drug and chronic kidney disease. But the authors identified many potentially serious drug-drug interactions, most of which were overlooked by the index guideline.

In general, few disease specific guidelines consider that target patients can also have other diseases, treated …