Methotrexate Therapy Guidelines

Introduction to Methotrexate Therapy

• The American Academy of Dermatology guidelines recommend that patients taking methotrexate should strictly avoid greater than moderate alcohol consumption, as it significantly increases the risk of methotrexate toxicity, particularly hematologic toxicity and hepatotoxicity 1, 2

Monitoring and Risk Management

• The American Academy of Dermatology guidelines recommend performing a complete blood count (CBC) before starting methotrexate treatment, and regular CBC monitoring every 3-6 months if no abnormalities are found, with more frequent monitoring (every 2-4 weeks) for 4-6 weeks after increasing methotrexate dosage 1, 2
• Liver function tests (LFTs) should be performed monthly for the first 6 months, then every 1-3 months thereafter, with more frequent monitoring recommended for patients with risk factors, including alcohol use 1, 2
• Non-invasive liver fibrosis assessment is recommended before starting treatment, especially for patients with risk factors for hepatotoxicity 2
• The following risk factors increase the risk of hepatotoxicity:

• Consider hepatitis B and C screening in patients with risk factors 4

Folate Supplementation and Side Effects

• Folate supplementation (1-5 mg/day given daily except on the day of methotrexate) is recommended to reduce the risk of hematologic toxicity and gastrointestinal side effects, according to the American Academy of Dermatology guidelines 1
• Common side effects such as nausea, vomiting, diarrhea, and stomatitis may be minimized by administering methotrexate intramuscularly or subcutaneously, splitting the dose, folate supplementation, and taking with food or at bedtime 1
• Folic acid supplementation reduces hepatotoxicity risk in patients taking methotrexate, as noted by the American Academy of Dermatology 2
• NSAIDs should be used with caution as they may increase methotrexate toxicity, and trimethoprim-sulfamethoxazole can increase bone marrow suppression 4

Special Considerations

• Complete abstinence from alcohol is the safest approach for patients on methotrexate therapy, especially for those with other risk factors for hepatotoxicity, as recommended by the American Academy of Dermatology guidelines 1
• Patients presenting with new pulmonary symptoms such as cough should be evaluated for pulmonary fibrosis, a severe but less common complication of methotrexate therapy 1
• Delayed toxicity, including pancytopenia, may occur up to 4-6 weeks after increasing methotrexate dosage, highlighting the importance of proper monitoring and risk factor management 1
• Psoriasis patients are at higher risk of developing fatty liver disease from methotrexate than patients with rheumatoid arthritis or inflammatory bowel disease, as reported in the Journal of the American Academy of Dermatology 2
• Methotrexate can cause various forms of liver damage, including elevated liver enzymes, fatty liver disease, progressive fibrosis, and cirrhosis in severe cases, as noted by the American Academy of Dermatology 2
• Adalimumab has not been associated with significant risk of fatty liver disease, unlike methotrexate, as reported in the Journal of the American Academy of Dermatology and Gut 2, 5
• TNF inhibitors like adalimumab do not require regular liver function monitoring specifically for hepatotoxicity and have not shown evidence of causing progressive liver fibrosis, according to Gut 5