Definition for Adrenergic drug
From Biology Forums Dictionary
Adrenergic drugs stimulate the adrenergic nerves directly by mimicking the action of norepinephrine. Therapeutically, these drugs are used in nasal decongestants as the main example given here.
The structures of the stimulants closely mimic the structure of the neurotransmitters and are thus able to interact with the receptor site. Adrenergic stimulants may have three modes of action: direct interaction with specific receptors (examples are epinephrine and phenylephrine); indirect action by stimulating release of neurotransmitters; or a mixed action involving both of the above (examples are phenylpropanolamine and ephedrine).