Ontario Paramedic Practice Exam

What drug is commonly used as a first-line treatment for anaphylaxis?

1. Aspirin

2. Epinephrine

3. Atropine

4. Diphenhydramine

The correct answer is: Epinephrine

Epinephrine is the first-line treatment for anaphylaxis due to its rapid-action capabilities in reversing severe allergic reactions. It works by stimulating both alpha and beta-adrenergic receptors, leading to vasoconstriction, increased heart rate, and bronchodilation. This combination of effects helps to counteract the life-threatening symptoms associated with anaphylaxis, such as airway swelling, hypotension, and severe respiratory distress. When someone experiences anaphylaxis, their body releases a large amount of histamine and other mediators, leading to a cascade of physiological changes. The timely administration of epinephrine can stabilize the patient's condition and prevent progression into more severe complications. This is why it is carried by paramedics and is emphasized in emergency response protocols. In contrast, other options like aspirin, atropine, and diphenhydramine serve different purposes. Aspirin is primarily used as an analgesic and anti-inflammatory medication, not for acute allergic reactions. Atropine is used to increase heart rate in symptomatic bradycardia and to manage certain types of poisoning, but it does not address the underlying anaphylactic response. Diphenhydramine, while an antihistamine that can help alleviate mild allergic symptoms, does not provide the