beta blocker beta blocker beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack (secondary prevention). they are also widely used to treat high blood pressure, although they are no longer the first choice for initial treatment of most patients. beta blockersdrug classskeletal formula of propranolol, the first clinically successful beta blocker.class identifierssynonymsbeta-blockers, β-blockers, beta-adrenergic blocking agents, beta antagonists, beta-adrenergic antagonists, beta-adrenoreceptor antagonists, beta adrenergic receptor antagonists, bbusehypertension, arrhythmia, etc.atc codec07biological targetbeta receptorsclinical datadrugs.comdrug classesconsumer reportsbest buy drugswebmdmedicinenet rxlist