Epinephrine is an injected medicine used to treat severe allergic reactions, breathing problems, and cardiac arrest.

Epinephrine:

• Stops further release of histamine and other chemicals, preventing an increasingly severe reaction.
• Narrows the blood vessels, which raises blood pressure. This may prevent the severe low blood pressure that occurs during a severe allergic reaction.
• Stops leakage of fluids from blood vessels into body tissues.
• Relaxes the muscles of the respiratory tract, relieving wheezing and breathing difficulty.
• Increases the heart rate.
• Makes the heart muscle more likely to respond to electrical shock treatment (defibrillation) for cardiac arrest.

A severe or fatal stroke, heart irregularity, or heart attack can occur if the wrong dose of epinephrine is mistakenly injected into a blood vessel or if an overdose is given.