Journal of Pharmacovigilance

Case report of drug interaction between Methotrexate and Rabeprazole

3^rd International Conference and Exhibition on Pharmacovigilance & Clinical Trials

October 27-29, 2014 Hyderabad International Convention Centre, India

Geetha S, Praveen Kumar Devarbhavi, Sathisha Aithal and Deepa Patil

Posters: J Pharmacovigilance

Abstract:

Introduction: Methotrexate (MTX) is used to treat various cancers and Autoimmune diseases. Over the past few years, data have appeared that indicate a potential interaction between MTX and proton pump inhibitors (PPIs). Concomitant use of these may increase the levels of MTXand its metabolite in the blood and lead to adverse reactions. History: An elderly female patient aged 50 yrs presented with complaints of excessive watery stools, with a frequency of about 5 times in 2 hours associated with colicky pain abdomen. She also complained of 2-3 episodes of vomiting. One day back she was prescribed with T. Rabeprazole 20mg for gastric discomfort. She is a known case of Rheumatoid Arthritis and is on treatment with Inj. MTX 25 mg once weekly + T. Hydroxychloroquine 200 mg OD along with folic acid and calcium supplementation. She also takes T. Naproxen 500 mg SOS for pain. She is a known case of hypothyroid and is on T. Levothyroxine 25mcg OD. She gave a similar history 2 months back noticed after taking T. Rabeprazole 20 mg. In both the episodes her laboratory findings were all within normal limits, except for mild derangement in the liver and renal function tests. She was asked to stop T. Rabeprazole and was advised T. Ranitidine 150 mg and the substitution resulted in resolution of the symptoms. Discussion and conclusion: The interaction could possibly be due to competition between MTX and PPI for the efflux transporters resulting in reduced elimination of MTX which in turn increase the risk of its toxicity. The causality assessment according to Naranjo algorithm shows the reaction to be probable. Hence, substitution with H2 blocker is recommended.

Biography :

Geetha S is doing her 2nd year post graduation in S S Institute of Medical Sciences under Rajiv Gandhi University of Health Sciences, Karnataka. Currently she is working on three more research projects: Antibacterial usage pattern in suspected neonatal sepsis in a tertiary care hospital, Anti depressant activity of Granisetron in albino mice and Drug utilization in MICU.