Hi Lorna,
Grapefruit Juice can increase or block the effects of some RA drugs, which in turn could lead to a greater risk of side effects.
http://news.bbc.co.uk/1/hi/health/4753747.stm
And a table of some of the drugs affected
http://ukpmc.ac.uk/artic...type=table&id=t1-25
If you're on Prednisolone
Grapefruit juice
Taking methylprednisolone with grapefruit juice has been shown to delay the absorption and increase the blood concentration of the drug.32 The mechanism by which grapefruit juice increases the concentration of methylpredniolone in the blood is not known, but it is suspected that it may interfere with enzymes in the liver responsible for clearing the drug from the body. In certain people, grapefruit juice may, therefore, enhance the effects of methylprednisolone. The combination should be avoided unless approved by the prescribing doctor.
So best to be on the safe side and not have grapefruit if you're unsure, or have a word with your GP Rheumatology team.
Hope this helps :)
Jo.
2012 Fundraising for the National Rheumatoid Arthritis Society (NRAS)
http://uk.virginmoneygiving.com/RoboJo