Metoprolol is a selective beta 1 receptor blocker used in treatment of several diseases of the cardiovascular system, especially hypertension. It is marketed under the brand name Lopressor or Lopresor, respectively, by Novartis, and Toprol-XL (in the USA); Selokeen (in Nederlands); as Minax by Alphapharm (in Australia), Metrol by Arrow Pharmaceuticals (in Australia), as Betaloc by AstraZeneca, as Neobloc by Unipharm (in Israel) and as Corvitol by Berlin-Chemie AG. A number of generic products is available, too. The active substance metoprolol is employed either as metoprolol succinate or metoprolol tartrate (whereas 100 mg metoprolol tartrate corresponds to 95 mg metoprolol succinate), as conventional release- or prolonged-release formulation.