Peripheral oedema after six weeks of amlodipine

A 62-year-old woman attends a follow-up appointment for hypertension and type 2 diabetes. Her blood pressure is well controlled on amlodipine 5 mg once daily, which was started six weeks ago. She also takes metformin 500 mg twice daily for diabetes, and uses ibuprofen 400 mg occasionally for knee pain (about three times per week). She reports gradual swelling of both ankles that began two weeks ago, approximately six weeks after starting amlodipine. The swelling is worse in the evenings and improves slightly with elevation. There is no associated pain, redness, or shortness of breath. On examination, she has bilateral pitting oedema extending from the ankles to the mid-shin. Heart rate is regular, 72 bpm; blood pressure 132/80 mmHg; jugular venous pressure is not elevated; lung fields are clear. She has no proteinuria; serum creatinine is 80 µmol/L (eGFR 90 mL/min/1.73 m²); liver function tests are normal; natriuretic peptide is within normal limits. An echocardiogram shows normal left ventricular systolic function with no significant valve disease. She has no personal or family history of venous insufficiency. Ibuprofen was continued unchanged during the period. She was asked to stop amlodipine for a trial off-drug. Within two weeks, the swelling had completely resolved, with no change in the other medications. She was not rechallenged with amlodipine. Her hypertension is now managed with ramipril 5 mg daily.