Methotrexate Prescribing Protocol for Rheumatoid Arthritis

Initial Dosing and Titration

The American College of Rheumatology recommends starting with oral methotrexate at 10-15 mg/week, with escalation of 5 mg every 2-4 weeks up to 20-30 mg/week depending on clinical response and tolerability 1, 2, 3, 4
Target a weekly dose of at least 15 mg within 4-6 weeks of initiation, with higher starting doses (25 mg/week) potentially more effective but with increased gastrointestinal toxicity 3, 5
Fast escalation (5 mg/month) to 25-30 mg/week shows higher efficacy but more adverse events than slow escalation 4, 6

Oral administration is recommended as the initial route, with consideration of switching to subcutaneous or intramuscular administration in case of inadequate response or intolerance 2, 3, 7
Subcutaneous administration has greater bioavailability and may provide higher clinical efficacy in early RA, though with potentially more withdrawal due to toxicity 5, 7

Before starting methotrexate, obtain clinical assessment of risk factors for methotrexate toxicity, patient education, laboratory tests (including AST, ALT, albumin, CBC, creatinine), and chest x-ray (within previous year) 1, 8
During treatment, monitor ALT/AST, creatinine, and CBC every 1-1.5 months until stable dose is reached, and then every 1-3 months, with clinical assessment for side effects at each visit 1, 3, 8

Prescribe at least 5 mg folic acid per week with methotrexate therapy to reduce gastrointestinal and liver toxicity without reducing efficacy 5, 8

Stop methotrexate if ALT/AST increases to greater than three times the upper limit of normal, and consider reinstituting at a lower dose after normalization of liver enzymes 1, 4
For patients not tolerating oral weekly methotrexate, consider split dosing over 24 hours or switching to subcutaneous injections 3, 4

Methotrexate is appropriate for long-term use based on its acceptable safety profile, and is favored as monotherapy over combination with other conventional DMARDs in DMARD-naive patients 1, 3, 6
Methotrexate can be safely continued during the perioperative period for patients undergoing elective orthopedic surgery, but contraception is essential and methotrexate should not be used for at least 3 months before planned pregnancy for both men and women 1