Sympathomimetics

Sympathomimetics are a class of drugs whose effects mimic those of a stimulated sympathetic nervous system. As such they increase cardiac output, dilate bronchioles, and usually produce constriction of blood vessels. Sympathomimetics include the naturally occurring substances such as adrenaline (epinephrine), noradrenaline (norepinephrine), dopamine, ephedrine, and cocaine, as well as the synthetic drugs pseudoephedrine, phenylephrine, phenylpropanolamine, amphetamine and methamphetamine, among others.

In medicine, certain sympathomimetics are commonly prescribed in cardiac emergencies including shock, asthma and anaphylaxis, in some cases for weight loss, and in cold remedies, where they shrink swollen membranes in the upper respiratory tract.

In recent years, phenylpropanolamine has been removed from over-the-counter cold formulations after it was implicated in causing an increased risk of hemorrhagic stroke.