Prescribing Analgesia for Knee Osteoarthritis in an Older Woman on Aspirin

Patient B-217, an 80-year-old woman, presents with worsening right knee pain over three months, causing difficulty with walking and stairs. The pain is worse with activity, eased by rest, and there is no significant morning stiffness. On examination, the right knee has bony swelling, crepitus, and reduced flexion but no effusion or warmth. Her body mass index is 27 kg/m² (weight 68 kg, height 1.59 m). She takes low-dose aspirin 75 mg daily for secondary prevention after a transient ischaemic attack. She has no known drug allergies. Blood pressure is 148/86 mmHg. Laboratory results: serum creatinine 1.0 mg/dL, eGFR 54 mL/min/1.73 m², alanine aminotransferase 25 IU/L, haemoglobin 12.5 g/dL. Radiograph of the right knee reveals joint space narrowing and osteophytes, consistent with osteoarthritis. She has used paracetamol occasionally with limited benefit. Prescribe an appropriate analgesic for this patient's knee pain and provide a follow-up plan.