Adrenergic drugs are also called sympathomimetic drugs because they produce effects similar to those produced by the sympathetic nervous system.
Classified by chemical…
Adrenergic drugs are classified into two groups based on their chemical structure’catecholamines (naturally occurring as well as synthetic) and noncatecholamines.
…or by action
Adrenergic drugs are also classified by how they act. They can be:
- direct-acting, in which the drug acts directly on the organ or tissue innervated (supplied with nerves or nerve impulses) by the sympathetic nervous system
- indirect-acting, in which the drug triggers the release of a neurotransmitter, usually norepinephrine
- dual-acting, in which the drug has both direct and indirect actions.
Which receptor does it affect?
The therapeutic uses of adrenergics’catecholamines as well as noncatecholamines’depend on which receptors they stimulate and to what degree. Adrenergic drugs can affect:
- alpha-adrenergic receptors
- beta-adrenergic receptors
- dopamine receptors.
Mimicking norepinephrine and epinephrine
Most adrenergics produce their effects by stimulating alpha receptors and beta receptors. These drugs mimic the action of norepinephrine and epinephrine.
Doing it like dopamine
Dopaminergic drugs act primarily on receptors in the sympathetic nervous system stimulated by dopamine.