Monitoring for Methotrexate Toxicity
McCarthy N, Mongey AB
Department of Rheumatology, St Vincent’s University Hospital
Methotrexate is used for a variety of inflammatory conditions, and is associated with the risk of adverse effects.
The study aims were to assess patient knowledge of, and adherence to blood monitoring standards in those being treated with methotrexate in the Rheumatology Department at SVUH.
Patients attending rheumatology clinics were interviewed using a standard proforma. Information including demographics, methotrexate dosage, mode of administration, duration of treatment, frequency and location of monitoring, and patient awareness and understanding of the importance of monitoring were obtained.
Forty patients were recruited, 12 (30%) male and 28 (70%) female. Mean age was 63.5 years, and the age range was 30-90 years. Duration of treatment ranged from 3 months to >20 years. Mean dose was 16.9mg, dose range was 7.5-25mg, and median dose was 20mg weekly. Nine (22.5%) patients were on injectable methotrexate.
Twelve patients (30%) were having blood tests less frequently than recommended guidelines (at an interval of no less than 3 monthly when dosage is stable)(1), with 9 patients (22%) undergoing monitoring at an interval of 6 monthly or less frequently.
Thirty-eight (95%) were aware of the necessity for monitoring; the 2 (5%) who were unaware were still in compliance with the recommended guidelines. Nine (22.5%) were unaware of the reasons for monitoring; however of those, 7 were still compliant with monitoring guidelines.
Thirty-five patients were attending either their GP (16) or SVUH (19) for monitoring, of these 5/16 (31%) and 7/19 (36.8%) were noncompliant, respectively. Patients receiving methotrexate for >5 years had compliance rates of 15/21 (71%).
In conclusion, 30% of the patients receiving methotrexate, attending SVUH rheumatology clinics were not compliant with recommended monitoring standards. There was no association between lack of compliance with monitoring and patient awareness of the need and reason for monitoring; location of monitoring; duration of treatment or mode of administration of methotrexate.
It is recommended that physicians reinforce the importance of monitoring with patients at clinic appointments.