This document discusses sympathetic drugs and their mechanisms of action. It describes direct-acting, indirect-acting, and mixed-acting sympathetic agonists (sympathomimetics) such as epinephrine, norepinephrine, dopamine, and various others. It also discusses sympathetic antagonists (sympatholytics) including adrenergic neuron blockers, adrenergic receptor blockers, beta blockers, and others. Various clinical indications and toxicities of these drugs are mentioned.