Final answer:
Sympathomimetic drugs can mimic the actions of the sympathetic nervous system by affecting adrenergic receptors and increasing levels of epinephrine and norepinephrine.
Step-by-step explanation:
The hormones that have the ability to duplicate the effects of the sympathetic nervous system are called sympathomimetic drugs. These drugs can bind to adrenergic receptors or increase the production of epinephrine and norepinephrine, mimicking the fight-or-flight response initiated by the sympathetic nervous system.
An example of such a drug is phenylephrine, which stimulates target organs similarly to how sympathetic activity would. Additionally, there are also drugs known as sympatholytic which block the sympathetic system's activity.