A 28-year-old male presents with a complaint of chronic low back pain and stiffness that has progressively worsened over the past year. The pain is particularly severe in the morning and improves with physical activity. He denies any history of trauma. Over the past few months, he has experienced occasional swelling in his right ankle and heel pain. Additionally, he reports fatigue and intermittent redness and pain in his left eye, which resolved spontaneously a few weeks ago. On physical examination, the patient appears thin with mild kyphosis of the thoracic spine. Examination of the spine reveals decreased lumbar flexion, demonstrated by a positive Schober test (3 cm). There is bilateral tenderness over the sacroiliac joints. Peripheral joint examination reveals mild swelling and tenderness in the right ankle, and tenderness at the Achilles tendon insertion. His eye examination is normal at the time of evaluation. Laboratory investigations show the patient is HLA-B27 positive, with elevated inflammatory markers (ESR and CRP). Imaging studies, including an X-ray, demonstrate bilateral sacroiliitis with joint space narrowing. An MRI of the sacroiliac joints confirms early inflammatory changes consistent with sacroiliitis. Which of the following treatments is considered first-line for pain and stiffness in this patient?
