P113 Is 3-monthly methotrexate monitoring necessary?

Abstract

Methotrexate, although effective and well tolerated, can cause cytopenia, raised liver enzyme levels and acute kidney injury, typically during the first few months of treatment. The BAD guidelines recommend 3-monthly blood monitoring indefinitely for patients on weekly methotrexate doses < 25 mg, despite limited supporting evidence. This study audited adherence to these monitoring guidelines in routine dermatology practice. We retrospectively reviewed patients prescribed methotrexate through the hospital pharmacy across dermatology departments in our region between April and September 2024. Patients receiving methotrexate via shared care general practitioner agreements or treated for < 6 months were excluded. In total, 53 patients were identified (mean age 43.7 years, range 6–84). Most were adults (87%, n = 46) with 51% (n = 27) being male. Underlying diagnoses were psoriasis (62%, n = 33), eczema (21%, n = 11) and other dermatoses (17%, n = 9). The median treatment duration was 17 months (range 6–105). All patients received folic acid supplementation. Only 58% of cases (n = 31) adhered to BAD monitoring recommendations (3-monthly full blood count, urea and electrolytes, liver function tests, plus procollagen-3 N-terminal peptide for psoriasis). Of 106 blood tests, 54.7% (n = 58) showed abnormal values, yet only four of these (7%) prompted clinical action. Alanine transaminase elevation occurred in 14.2% (n = 15), and clinically significant cytopenias in 0.9% (n = 1). None required drug discontinuation. This audit demonstrated suboptimal adherence to BAD monitoring guidelines. Clinically significant cytopenia, elevated liver enzymes and acute kidney injury requiring methotrexate discontinuation were rare after the first 6 months of treatment. Most laboratory abnormalities required no intervention. Risk-stratified monitoring for methotrexate toxicity using prognostic models could be considered. Low-risk patients could undergo annual testing, whereas those at moderate-to-high risk should maintain the current, more frequent testing schedule.