A 42-year-old woman presents with a 6-month history of joint pain and stiffness affecting her hands (MCP and PIP joints), wrists, and feet, worse in the morning and lasting over an hour. She also reports fatigue. Examination reveals symmetrical swelling and tenderness of the MCP and PIP joints. Rheumatoid factor is positive and anti-CCP antibodies are elevated. What is the most appropriate initial disease-modifying antirheumatic drug (DMARD) to offer according to NICE NG100?