Adverse drug reactions caused by methotrexate in Saudi population

Aim: The aim of this study is to document adverse drug reactions (ARDs) of methotrex- ate (MTX) in Saudi patients. Methods: Cross sectional study of adult patients on MTX, attending rheumatology drug mon- itoring clinics in a university hospital, over a period of 24 weeks. Adverse drug reactions were sought by patient interview, files review and laboratory abnormalities. Results: Data collected included patients’ demographics, diagnoses, co-morbidities, MTX dose and duration, other medications, laboratory abnormalities and adverse reactions, their severity, preventability, and outcome. Out of a total of 593 patients screened, 186 (31.4%) using MTX were interviewed. Most of the patients were female (88.5%). Adverse drug reactions (ADRs) were detected in 61 patients (32.8%). Patients with ADRs took a mean dose of 12.9 mg (2.5–22.5 mg). Ten ADRs (16.4% of total reactions) were preventable; they ranged between severe, moderate and mild. The most common ADRs were gastrointestinal (GI) (52.5%), followed by anemia (8.2%) and chest tightness (6.6%). The duration of the reaction ranged from few hours to 4 years. Conclusion: In conclusion our patients with adverse reactions were younger, took less medica- tions and had less co-morbidities. Our results were different from those published in the literature relating MTX toxicity.