Practolol (Eraldin, Dalzic, Praktol, Cardiol, Pralon, Cordialina, Eraldina, Teranol) is a selective beta blocker (beta-1 blocker) that has been used in the emergency treatment of cardiac arrhythmias. Practolol is no longer used as it is highly toxic despite the similarity of its chemical formula to propranolol. [Source: Wikipedia 
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