Seloken ZOK / Toprol-XL (metoprolol CR/XL) is the world's leading cardioselective beta-blocker for hypertension, angina pectoris, heart failure, disturbances of cardiac rhythm including especially supraventricular tachycardia, maintenance treatment after myocardial infarction and functional heart disorders with palpitations and for migraine prophylaxis.

Seloken ZOK / Toprol-XL is the most widely prescribed drug in its class. The development of the advanced controlled-release formulation (CR/XL - ZOK), which ensures even plasma concentrations over 24 hours from one daily dose, has kept Seloken ZOK / Toprol-XL at the forefront of cardiovascular therapy.

The most recent indication, heart failure, follows positive results of the Metoprolol CR Randomised Intervention Trial in Heart Failure (MERIT-HF), a study assessing the benefits of adding Seloken ZOK / Toprol-XL to standard therapy for chronic heart failure. The results demonstrated that the relative risk for total mortality was reduced by 34%, cardiovascular mortality was reduced by 38%, sudden death was reduced by 41% and death due to worsening heart failure was reduced by 49%.