On-call scenario 7: Sources
Information sources that you might have thought about looking in, include:- BNF
- SmPCs via the emc or MHRA
- Stockley’s Drug Interactions (if you have access)
- Micromedex (if you have access)
- NICE has published lots of guidance on antimicrobial prescribing
- SPS has some helpful guidance called Identifying risk factors for developing a long QT interval
You check your local policy and NICE guidelines and are reassured that clarithromycin is a suitable antibiotic choice for this patient.
The SmPC for citalopram contraindicates its use with other drugs that prolong the QT interval because of the additive risk. Therefore, according to the UK licence, the combination would be contraindicated. Clarithromycin may also increase the plasma levels of citalopram through a CYP3A4 mediated interaction and could put the patient at a further increased risk of side effects.
Now that you have this information, how will you advise the registrar?
Now that you have this information, how will you advise the registrar?