How does epinephrine treat anaphylaxis?

Epinephrine is the first medication used to treat anaphylaxis. When administered promptly, it is lifesaving. Epinephrine (also known as adrenaline) increases blood pressure by constricting blood vessels (thereby preventing cardiovascular collapse), prevents or decreases swelling of the airways and promotes dilation of the airways (allowing air to better flow to and from the lungs), decreases the activity of mast cells and basophils (both of which release mediators that cause inflammation), and helps the heart beat more effectively (promoting blood flow).^[1] Adverse effects include anxiety, restlessness, palpitations, headache, dizziness, pallor, and tremor.^[2] Serious adverse effects, like dangerous heart arrhythmias, are rare.^[3]

Although epinephrine rapidly treats most of the dangerous symptoms of anaphylaxis, it is not a “cure” for allergic reactions or a replacement for immediately seeking medical help. Instead, epinephrine auto-injectors are a way to prevent serious complications from occurring before being seen by a clinician for additional evaluation and care. In some cases, additional medications may be needed to fully treat someone’s symptoms, or the allergic symptoms may return even after they initially resolved. Thus, medical monitoring is important after using auto-injectors.