Hyperkalaemia on aliskiren (RASILEZ) plus enalapril (XANEF, generics): A 72-year-old pensioner with diabetes and stage 3 chronic kidney disease was taking the renin inhibitor aliskiren (RASILEZ; a-t 2007; 38: 81-2) for her hypertension in addition to long-term medication with the ACE inhibitor enalapril (XANEF, generics) and the thiazide diuretic hydrochlorothiazide (e.g. ESIDRIX). After five weeks of uptitrated treatment, she developed bradycardia (38 beats per minute) with palpitations and dizziness. On admission to hospital she had hyperkalaemia of 6.0 mmol/l and an elevated creatinine level of 2 mg/dl. Her blood pressure was 200/70 mmHg. Aliskiren and enalapril were discontinued. In response to the cation exchanger polystyrene sulphonate (e.g. RESONIUM), infusion of saline and furosemide (LASIX, generics), potassium levels and heart rate returned to normal and renal function improved (NETZWERK Report 15.723). The prescribing information (SPC) of aliskiren warns against hyperkalaemia when taking aliskiren in conjunction with other medicines that inhibit the renin-angiotensin system, in patients with impaired renal function or diabetes (Novartis Pharma: RASILEZ SPC, dated June 2010). Compared with monotherapy with aliskiren or ramipril (e.g. DELIX) the combination doubles the risk of clinically relevant hyperkalaemia in diabetics (> 5.5 mmol/l: 2.2% and 2.6% respectively versus 5.5%; URESIN, Y. et al.: J. Renin Angiotensin Aldosterone Syst. 2007; 8: 190-8). There are no long-term studies that demonstrate any benefit of aliskiren alone or in combination with regard to cardiovascular morbidity or mortality, -Ed.