Adrenergic antagonists, also called adrenolytics, inhibit in a competitive way the effects of catecholamines. These antagonists are molecules having high affinity for adrenergic receptors without the capacity to activate them or only slightly. They prevent endogenous catecholamines from exerting their effects. Inhibition is more apparent when the stimulation by endogenous catecholamines is important.
These antagonists inhibit specifically alpha, beta or dopaminergic adrenergic receptors.