AB1178 Comparison of the prevalence of proxy- or self-reported side effects of methotrexate administered orally, subcutaneously or intramuscularly in children with juvenile idiopathic arthritis

Background Methotrexate (MTX) is the disease-modifying medication of first-choice for the treatment of juvenile idiopathic arthritis (JIA). Although serious adverse effects are rare, MTX intolerance, particularly gastrointestinal discomfort, is frequently observed. However, it is unclear whether the prevalence of adverse events varies across different routes of administration. Objectives To compare the rate of parent proxy-reported or child self-reported side effects of MTX administered orally, subcutaneously or intramuscularly. Methods The parents of children with JIA who were seen at our center from March 2007 and September 2011 and were receiving MTX therapy were asked to complete the proxy-report version of the Juvenile Arthritis Multidimensional Assessment Report (JAMAR), which includes a checklist of medication side effects. The self-report version of the same questionnaire was also completed by children, if aged more than 7-8 years. The JAMAR lists 18 side effects and offers the possibility to record up to 2 side effects not included in the list. MTX therapy was started in all patients, irrespective of the route of administration, at 15 mg/m2/week. All patents were given folate supplementation with folinic acid. Results The JAMAR was completed by 337 parents in 1007 visits and by 183 children in 419 visits. The frequency of parent proxy-reported side effects by route of administration is shown in the Table. Table 1. Frequency of side effects by route of administration (parental evaluations) Side effectRoute of administration Oral, % (N=431)Subcutaneous, % (N=289)Intramuscular, % (N=287) Nausea15.117.621.3 Mood swings13.914.58.4 Stomach pain/burning139.79.1 Headache8.41011.5 Weight gain5.84.85.2 Sleep disturbances5.62.43.8 Mouth sores4.95.25.2 Vomiting4.910.76.6 Conclusions The frequency of nausea and vomiting was greater in children receiving MTX parenterally than in those on oral MTX. Children taking MTX orally had more frequently stomach pain/burning or sleep disturbances than those on parenteral MTX. Disclosure of Interest None Declared