CIEMT Medical and Physiology Practice Exam 2026 - Free Practice Questions and Study Guide

Drugs that directly mimic the sympathetic nervous system activate adrenergic receptors or boost the action of catecholamines, producing “fight-or-flight” effects like increased heart rate, bronchodilation, and pupil dilation. This direct imitation is what defines sympathomimetics. They work by acting as receptor agonists at alpha or beta adrenergic receptors or by increasing norepinephrine/epinephrine levels to enhance sympathetic signaling. That’s why this category best fits the idea of directly mirroring sympathetic activity. In contrast, sedatives calm the CNS, stimulants broadly boost CNS activity without specifically replicating sympathetic signaling, and antipsychotics mainly block dopamine receptors rather than simulating sympathetic output.