SPS resources

SPS has a variety of resources on drug interactions which we recommend you check first. For example Using miconazole oral gel with statins describes the potential interaction and provides advice on prescribing miconazole for patients taking different statins.

If the information is not available on the SPS website or the information resources listed, or if your clinical scenario is complex, we would suggest you seek further advice from our Medicines Advice service.

Other primary resources

In addition to our own resources, we particularly recommend the following resources. They are free to access unless indicated otherwise:

British National Formulary

When looking for interactions between medicines, we recommend using the BNF and BNFC as mobile apps (registration required) or via Medicines Complete (needs an NHS England OpenAthens account).

This allow users to search for interactions between multiple medicines.

Information is provided for each pair of interacting drugs.

Register for an NHS England OpenAthens account

Summaries of Product Characteristics

SmPCs/SPCs are available via electronic Medicines Compendium and MHRA. They list interactions with other medicinal products and other forms of interaction in section 4.5.

Other useful sections include:

• contraindications (4.3)
• special warnings and precautions for use (4.4)
• pharmacodynamic properties (5.1)
• pharmacokinetic properties (5.2)

Stockley’s Drug Interactions

Available to subscribers via Medicines Complete, monographs in Stockley’s Drug Interactions describe the evidence, mechanism, clinical importance and management of over 4,500 drug interactions.

The Interaction Checker allows users to search for interactions between multiple medicines; information is provided for each pair of interacting drugs, with links to the full Stockley monographs.

Secondary resources

The following resources are useful for finding information in specific areas and are freely available:

Cancer drug interactions

The interactive Cancer drug interaction checker allows users to select cancer medicines and co-medications.

Results are graded from ‘medicines should not be co-administered’ to ‘no clinically significant interaction expected’ and note if further monitoring or dose adjustment are required.

Contraceptive medicines interactions

The Faculty of Reproductive and Sexual Healthcare has issued advice on interactions with hormonal contraceptives.

HIV drug interactions

The interactive HIV interaction checker allows users to select HIV drugs and co-medications they are interested in.

Results are graded from ‘these medicines should not be co-administered’ to ‘no clinically significant interaction expected’ and note if further monitoring or dose adjustment are required.

The prescribing resources section of the site provides further information including summary tables of drugs interactions and fact sheets for HIV medicines.

QT-interval interactions

The US site CredibleMeds (access is free but users must be registered) provides a searchable database of medicines that prolong the QT interval and/or induce Torsades de Pointes (TdP).

Drugs are categorised according to risk: known risk, possible risk or conditional risk of TdP.

A page showing therapeutic options not on the QT drugs list shows, by indication, medicines that are and are not in the QT risk categories.

Questions around TdP risk, including the criteria used to assign drugs a risk category for the database, are answered in FAQs for Healthcare Professionals.

Viral hepatitis drug interactions

The hepatology drug interaction checker provides information on interactions with medicines used in chronic hepatitis C infection. Users can select hepatology drugs and co-medications.

Results are graded from ‘these medicines should not be co-administered’ to ‘no clinically significant interaction expected’ and note if further monitoring or dose adjustment are required.

Training resources

If you would like more information on how to approach answering questions on drug interactions we recommend:

Medicines Learning Portal

The Medicines Learning Portal is aimed at trainee hospital pharmacists but the content is also relevant to clinical primary care healthcare professionals. The portal includes a tutorial on drug interactions which provides advice on:

• questions to ask when considering questions relating to drug interactions
• mechanisms of drug interactions
• managing and monitoring drug interactions
• how to talk to patients about drug interactions

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