Epinephrine is used to treat severe allergic reactions, such as anaphylaxis, and other medical emergencies. Also known as adrenaline, epinephrine is a powerful drug that can interact with other medications and supplements. Dr Christian Nageotte, service chief of allergy and immunology at Henry Ford West Bloomfield Hospital, explains that while interactions can cause temporary effects like an abnormal heart rate or sudden changes in blood pressure, “All of these risks are very temporary.” He adds that “Epinephrine moves out of the body so quickly,” with most interactions lasting only about 20 minutes.
Epinephrine is a naturally occurring hormone that activates the body’s “fight or flight” response, increasing heart rate and blood pressure, improving breathing, and diminishing other allergic reactions. In cases of anaphylaxis, the body floods with chemicals like histamine, causing a significant drop in blood pressure and narrowed airways. As Dr Mario Rodenas, an allergist and immunologist at Yale Medicine, explains, “If you have a life-threatening reaction, epinephrine is the single most important drug you can use.” He notes that it “relaxes the muscles in the airway, allowing for better breathing, and increases the heart rate and blood pressure so that the blood continues to flow to all the major organs. It also stops the release of histamine, the main chemical released by the body in response to allergens that cause allergy symptoms.”
Doctors recommend that individuals at risk of anaphylaxis carry two doses of epinephrine. A study in the Journal of Allergy and Clinical Immunology found that about one in 10 anaphylaxis reactions required more than one dose, and a separate report in the same journal suggests that a poor response to two doses indicates the need for more intense, prompt medical care, such as an intravenous infusion.
Epinephrine can interact with other drugs, either by increasing side effects or reducing its effectiveness. Nageotte notes that some of the most common interacting medications are those for blood pressure. For example, beta blockers can complicate epinephrine’s effects by blocking stress hormones, which “can cause a rapid swing in blood pressure,” and potentially lead to a temporary arrhythmia. Other interacting drugs include diuretics, antihistamines, certain antidepressants like monoamine oxidase (MAOI) inhibitors, and other blood pressure-lowering medications like alpha blockers, nitrates, and calcium channel blockers.
Certain supplements, especially those with stimulants like St John’s wort and ephedra, can also cause complications such as arrhythmias or blood pressure spikes. However, Nageotte says there are no known direct interactions between an epinephrine and caffeine, although he cautions against potent energy drinks that contain additional stimulants and sugar. There are no known interaction concerns between epinephrine and alcohol, but alcohol can impair judgment and cause symptoms, such as flushing and dizziness, which can be confused with early signs of anaphylaxis. Additionally, a dose of epinephrine is unlikely to interact with most common vaccines and can actually help lessen the severity of a vaccine-related allergic reaction.
Despite the potential for drug interactions, experts emphasize that the risk of anaphylaxis is far greater than the temporary side effects from an epinephrine. “The risk of anaphylaxis is always going to be greater than a temporary change in blood pressure or an arrhythmia,” Nageotte says. He strongly advises against hesitation, stating, “You don’t want to hesitate to use epinephrine,” as waiting even a few minutes can lead to an unfortunate outcome and make it more difficult to revive someone from anaphylactic shock.
Individuals should inform their prescribing physician about all the medications, supplements, and even lifestyle factors they have. By doing so, they can ensure their healthcare provider understands their situation and can provide proper guidance on epinephrine use and storage, managing any potential risks or complications.
