 These are drugs that block the effects of beta noradrenergic receptors while having little or no effect on alpha receptors . They are sometimes used to treat high blood pressure , atrial fibrillation and congestive heart failure , but recent reviews have concluded that other types of drugs are usually superior for those purposes . Beta blockers may be a viable choice for other cardiovascular conditions , though , including angina and Marfan syndrome . They are also widely used to treat glaucoma , either in pill form or in eyedrops . Because of their effects in reducing anxiety symptoms and tremor , they have sometimes been used by entertainers , public speakers and athletes to reduce performance anxiety , although they are not medically approved for that purpose and are banned by the International Olympic Committee . 
