American Journal of Pharmacological Sciences, 2013, Vol. 1, No. 4, 53-55 Available online at http://pubs.sciepub.com/ajps/1/4/2 © Science and Education Publishing DOI:10.12691/ajps-1-4-2 The Effect of Methotrexate in Rheumatoid Arthritis Patients is Reduced by Tea Consumption Ehab M. Mikhael * , Samer I. Mohammed University of Baghdad, College of Pharmacy, Clinical Pharmacy Department, Bagdad,Iraq *Corresponding author: ehab_pharma84@yahoo.com Received May 09, 2013; Revised May 23, 2013; Accepted May 24, 2013 Abstract 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. Keywords: rheumatoid arthritis, methotrexate, adenosine, disease activity, tea 1. Introduction Rheumatoid arthritis (RA) is a common systemic inflammatory disease of unknown etiology [1]. Methotrexate (MTX) is one of the most important drugs for the standard care and the management of RA [2]. The most acceptable explanation of the anti-inflammatory mechanism of MTX is through the inhibition of 5- aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase enzyme, this inhibition lead to intracellular AICAR accumulation, and since AICAR inhibits AMP deaminase and adenosine deaminase, AICAR accumulation could lead to the release of AMP (which may be dephosphorylated to adenosine) and/or adenosine [3]. Adenosine is a potent endogenous antiinflammatory mediator which acts by binding to specific receptors on the surface of lymphocytes, monocytes, and neutrophils, to down regulates inflammatory pathways [3,4,5,6]. It was found that adenosine receptor antagonists like caffeine and deletion of adenosine receptors reduce the anti- inflammatory response to methotrexate not only in animal studies but also in clinical trials for patients with rheumatoid arthritis [7,8,9]. Tea is one of the most popular drinks in the world [10] and especially in Iraq [11]. Different types of tea that usually consumed in Iraq contains large amount of caffeine [12]. However till now there is no any study to assess the effect of tea consumption on MTX, so this study aimed to evaluate the effect of tea consumption on the response to MTX in RA patients. 2. Methods 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. Patients were diagnosed to have RA by rheumatologist according to revised 1987 American College of Rheumatology (ACR) classification criteria for RA [13]. Patients with diseases other than rheumatoid arthritis were excluded from the study. Demographic data of patients were reported regarding their age, gender, duration of the disease, and medication history (Table 1). RA Disease activity was assessed in all patients by clinical disease activity index (CDAI), which was shown to be a valid and reliable measure for assessment of Iraqi patients with active RA(14). It was measured by palpation of bilateral knees, shoulders, elbows, wrists, metacarpophalangeal and proximal interphalangeal joints, to count the number of tender (TJC) and swelling joints (SJC). Patient (VAS) and physician global assessment (EGA) were also measured using visual analogue scale VAS of 0-10cm. CDAI = TJC + SJC + VAS + EGA CDAI values less than 2.8 considered as remission; CDAI>2.8≤10