Intended for healthcare professionals

Rapid response to:


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

BMJ 2015; 350 doi: (Published 11 March 2015) Cite this as: BMJ 2015;350:h1059

Rapid Response:

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

We agree with the points Marengoni and Onder make about drug-drug interactions, the paucity of evidence on this topic restricts our collective understanding and increases the risk of harm to patients. This is compounded by the opaque routes that patients and clinicians can access the limited evidence that we do have.

The current 'yellow card' system in the UK is one way that drug-drug interactions can be reported, although this system is open to patients and clinicians it is not well understood or widely used by either group.

We explored this topic in relation to patients who have co-occurring mental health and substance use problems (1), these patients are more likely to be poly drug users which increases the potential for drug-drug interactions, adding three other potential groups of drugs into the mix:
1. illicit drugs
2.misuse of prescription drugs
3. novel psychoactive substances (legal highs)

It is important to recognise that not all adverse drug interactions are unwanted by those who experience them, some of these reactions may be desired by some individuals.

The main reference for clinicians is the BNF, which has a whole appendix devoted to drug interactions, however this has very limited information when it comes to recreational or problematic drug use. Again we would agree with Marengoni and Onder in their two main pleas, firstly to provide new electronic tools which could provide the information we do have in a more accessible format and secondly to encourage all clinicians to assess patients which could feed into the first suggestion and help our collective understanding on this topic.

1. Hamilton, I., & Pringle, R. (2013). Drug interactions and dual diagnosis. Advances in Dual Diagnosis, 6(3), 145-150.

Competing interests: No competing interests

12 March 2015
Ian Hamilton
Rose Pringle
University of York
Health Sciences, Heslington, York