A 62-year-old woman starting methotrexate for rheumatoid arthritis has been prescribed folic acid. What is the most important counselling point?

• A. Take methotrexate daily and monitor liver function regularly
• B. Take methotrexate once weekly and report signs of sore throat or mouth ulcers
• C. Take methotrexate twice daily with food
• D. Take folic acid only if you develop mouth ulcers

Answer: (B)

Methotrexate for rheumatoid arthritis is given once weekly, not daily, because taking it more often dramatically increases the risk of serious toxicity to rapidly dividing cells such as those in the bone marrow and gut. Folic acid is added to reduce some of these toxic effects, but it does not change the need for weekly dosing. Therefore, the most important counselling point is to take methotrexate once weekly and to watch for signs of bone marrow suppression, especially sore throat or mouth ulcers, and report them promptly. These signs can indicate early cytopenia and infection risk, which require medical attention.