A 71-YEAR-OLD man with a background of coronary artery disease (proximal LAD 80—90% stenosis, RCA 40% stenosis), severe mitral regurgitation, type 2 diabetes, glaucoma, hyperlipidaemia, hypertension and diverticular disease undergoes coronary artery bypass grafting (LIMA to LAD) and mitral valve repair. Postoperatively he develops hyponatraemia (Na+ 130, K+ 4.1), pleural effusions and AF. His sodium normalises to 135mmols/L with fluid restriction and his effusions are drained. He is commenced on amiodarone with a 300mg IV bolus then 200mg PO tds with reversion to sinus rhythm. His other medications include CoPlavix, oxycodone prn, perindopril, metformin, esomeprazole, latanoprost, brimonidine and timolol eye drops, colchicine and rosuvastatin.