The Effect of Methotrexate in Rheumatoid Arthritis Patients is Reduced by Tea Consumption

Rheumatoid arthritis (RA) is a common inflammatory disease. Methotrexate (MTX) is the most important drug for RA treatment; it acts as anti inflammatory drug by increasing adenosine level. Adenosine receptor antagonists reduce the anti inflammatory effect of MTX. Tea is a popular drink in Iraq contain large amount of caffeine, this study aimed to evaluate the effect of tea consumption on the response to MTX in RA patients. A cross-sectional study was conducted in Baghdad Teaching Hospital, Rheumatology Unit from September 2012 to April 2013. A total of 25 RA patients (5 males and 20 females) who were treated by using MTX for at least 3 consecutive months and drink tea daily were included in this study. RA Disease activity was assessed in all patients by clinical disease activity index (CDAI). A direct interview with all patient were done, each patient was asked about their tea intake and the size of cup used. This study showed that the average consumption of tea per day for each patient was approximated to 8 small cups, this high level of consumption was associated with a high value of RA disease activity as measured by CDAI in greater than the half of patient who participated in this study. There is a direct positive correlation between evaluator global assessment and swelling joint count with tea consumption. In conclusion tea consumption decreases the effectiveness of MTX in Iraqi patients with rheumatoid arthritis.