A 50-year-old woman presents with a 3-month history of pain and stiffness in her hands, wrists, and feet, worse in the mornings and lasting over an hour. She also feels fatigued. Examination reveals symmetrical swelling and tenderness of her MCP and PIP joints. Rheumatoid factor is positive and anti-CCP antibodies are elevated. According to NICE NG100, what is the most appropriate initial disease-modifying antirheumatic drug (DMARD) strategy?