Methotrexate Monitoring Guidelines

Introduction to Methotrexate Monitoring

• The American Academy of Dermatology recommends monitoring complete blood count, liver function tests, and renal function every 3-4 months after initial stabilization, with more frequent monitoring during the first month and after dose increases 1, 2

Baseline Testing Before Initiation

• The American Academy of Dermatology recommends obtaining complete blood count with differential and platelet count, liver function tests, serum creatinine and renal function tests, hepatitis B and C serologies, chest X-ray, and pregnancy test in women of childbearing potential before starting methotrexate 1, 2, 3
• Baseline liver biopsy is not recommended, even in patients with risk factors for hepatotoxicity 1, 4, 3

Regular Monitoring Schedule

• The American Academy of Dermatology recommends monitoring CBC, liver function tests, and renal function every 2-4 weeks during the first month and after dose increases 1, 4, 2
• The American Academy of Dermatology recommends monitoring CBC, liver function tests, and renal function every 3-4 months for stable patients 1, 2

Monitoring for Specific Toxicities

• The British Association of Dermatologists recommends monitoring serum PIIINP at least every 3 months in psoriasis patients, with referral for specialist assessment if PIIINP is >8 mg/L on two occasions, or three measurements >4.2 mg/L in 12 months, or >10 mg/L on one occasion 4, 6
• The American Academy of Dermatology recommends monitoring for hepatotoxicity, hematologic toxicity, and renal function toxicity 1, 5, 2

Folate Supplementation

• The British Association of Dermatologists recommends folic acid supplementation to reduce adverse events and improve tolerability, with typical dosing of 1-5 mg daily, taken 6 days per week 4, 2, 3

Patient Education and Safety

• Patients must understand the weekly dosing schedule, seek urgent medical attention for fever/flu-like illness, mouth ulceration, unexplained bruising or bleeding, severe sore throat, nausea/vomiting/abdominal pain, or breathlessness, limit alcohol intake, use effective contraception, and omit methotrexate dose during intercurrent illness causing dehydration 4, 3, 6

Common Pitfalls to Avoid

• Do not check liver function tests within 2 days of methotrexate dose, as transient elevations are common and may lead to unnecessary dose adjustments 2, 3
• Do not perform routine surveillance liver biopsies, as they are no longer recommended and carry significant morbidity risk 1, 4, 6