Interactions: Information sources

Last updated: Thursday, November 23, 2017

Stockley’s Drug Interactions tends to offer practical advice on patient management, but it does not cover all interactions.

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The SmPCs for medicines often identify interactions. Make sure you check the Contra-indications, Special Precautions, Undesirable Effects, and Interactions sections of an SmPC because relevant information may appear in any of these places. Don't rely on the Interactions section alone. Some interactions may be listed because they could occur in theory rather than being a proven problem in clinical practice (e.g. where cytochrome p450 is a minor part of a drug's metabolism). Use other sources to differentiate between actual and theoretical concerns.

We have a general learning module on using SmPCs via the eMC here.

If you need to establish whether a drug is an inducer, inhibitor or substrate of cytochrome p450, then the Transformer website is comprehensive, although it is a technical/scientific resource rather than a clinical one.

There are three valuable websites for interactions in therapeutic areas where regimens can be complex. They let you enter all the medicines involved and check for interactions:


The subscription sources Martindale, AHFS Drug Information, Lexicomp or Micromedex can be useful additional resources for interaction enquiries. If your enquiry involves an alternative medicine, then you may need to refer to some of the sources listed in that tutorial to help you.

Be careful about conducting a general internet search on this subject. If you do, you may like to look at our brief guide to evaluating websites about medicines.

Presenting your answer 

Once you’ve asked sufficient questions, gathered the information required and assessed it, you’ll need to provide an answer. We can offer you some general guidance on answering clinical problems.