Dopamine agonists used for Parkinson's disease and ADHD act most similarly to which category of medications?

• A. Anticholinergics
• B. Cholinergic agonists
• C. Adrenergic agonists
• D. Adrenergic antagonists

Answer: (C)

Dopamine agonists work by directly stimulating dopamine receptors, which are part of the catecholamine signaling system. Because dopamine is a catecholamine like norepinephrine and epinephrine, drugs that activate dopamine receptors resemble the actions of adrenergic agonists, which stimulate adrenergic receptors activated by these catecholamines. So dopamine agonists produce effects similar to those of adrenergic receptor activation, making them most like adrenergic agonists.

Anticholinergics would oppose acetylcholine signaling, cholinergic agonists mimic acetylcholine, and adrenergic antagonists block adrenergic receptors, none of which align as closely with how dopamine agonists work.