Intended for healthcare professionals


Drug-grapefruit juice interactions

BMJ 2013; 346 doi: (Published 07 January 2013) Cite this as: BMJ 2013;346:f1

Re: Drug-grapefruit juice interactions

I've always wondered about the science behind why Grapefruit Juice was to be avoided when using Simvastatin. So it was useful to read the editorial from Professor Munir Pirmohamed.

This focuses on the mechanisms but gives no insight that is particularly useful when talking with patients. Simvastatin has a proven track record in primary and secondayr prevention through multiple trials. WHenever cosiderig a Statin in Primary prevention following QRisk Assessmnet, as part of informed choice I discuss both relative percentage reduction in Risk and Absolute numbers needed to treat to prevent a Cardiovascular event.

With the theoretical risks for mixing Grapefruit and Simvastatin (and the other drugs listed) I do not have information on relative risk of harm or absolute numbers needed to harm from the GFJ+Drug combaintions.

The rapid response from BakMan and Bakhai (A local cardiologist to me) helps. GFJ has its own benefits. Numbers neeeded to Harm from the experience they report over 10 years seems so high they have not been able to establish.

In practice what does this mean for me?
If patients have been on simvastatin for a long time I do not feel I would be able to persuade them to change to another Statin based on the available information. Even more so if they are on Atorvastatin.

If they do want to change then pravastatin will be my first (most cost efective) recomendation.

If they are on Simvastatin/Atorvastatin and ask whehter they can drink GFJ I will say their are theoretical risks though the experience of at least one of our local Cardiologists and their colleagues is that they are not aware of anyone coming to any harm over the last 10 years.

Any pragmatic improvements on this approach would be appreciated.

It is reassuring to see the response from

Competing interests: No competing interests

27 January 2013
Patrick McDaid
Heahtfielde Medical Centre
8 Lyttelton Road Hampstead Garden Suburbs London N2 0EQ