Injection compatibility: Information sources

Last updated: Thursday, November 18, 2021

American Society of Health-System Pharmacists Injectable Drug Information is a good starting point if you are asked about mixing drugs. Remember that medicines will be listed under their US names and not all UK drugs are included. A key disadvantage is that the concentrations included do not always represent what is used in clinical practice here in the UK. This may mean you have to make a judgement about their relevance.

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If this isn’t helpful then try the online Injectable Medicines Guide monographs. Compatibility data may also be found in the Document library on the left-hand side of the home page. This database will also tell you about the pH of injections.

If you have access, then Micromedex has an IV medicines compatibility checker. As a US resource, the same limitations of the ASHP Injectable Drug Information apply as above.

SmPCs are rarely helpful if you are asked about mixing drugs, but can help you with questions around the choice of diluent to use. Alternatively, consider contacting the product manufacturers for any in-house data they may have.

For enquiries about mixing drugs in syringe drivers, especially in the palliative care context, Andrew Dickman’s The Syringe Driver is an excellent resource (Oxford University Press). You can read some general information about syringe drivers on this page of the palliative care tutorial.

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. As a reminder, we offer some general guidance on answering clinical problems. You might like to refresh your memory if you’ve not looked at this recently.