Atenolol

Atenolol is a selective β₁ receptor antagonist, a drug belonging to the group of beta blockers (sometimes written β-blockers), a class of drugs used primarily in cardiovascular diseases. Introduced in 1976, atenolol was developed as a replacement for propranolol in the treatment of hypertension. It works by slowing down the heart and reducing its workload. Unlike propranolol, atenolol does not readily pass through the blood–brain barrier, thus decreasing the incidence of central nervous system side effects.