Medical Emergencies · single question
A patient develops anaphylaxis. What medication will you administer?
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Correct answer: D. Epinephrine 1:1,000 (IM)
- A. Diphenhydramine is a SECONDARY medication for anaphylaxis — given AFTER epinephrine. It does NOT treat the life-threatening bronchospasm and cardiovascular collapse of anaphylaxis. Giving antihistamine INSTEAD OF epinephrine is a dangerous delay.
- B. Epinephrine 1:10,000 is used for CARDIAC ARREST via IV. For ANAPHYLAXIS, the IM dose is 1:1,000. Using 1:10,000 IM would deliver an inadequate dose.
- C. Corticosteroids are SECONDARY medications for anaphylaxis given to prevent biphasic reactions — they are too slow to treat the immediate crisis. Epinephrine is always first.
- D. Epinephrine 1:1,000 (0.3-0.5 mL IM into the anterolateral thigh) is the FIRST-LINE treatment for anaphylaxis. It acts on α1 receptors (vasoconstriction, reverses hypotension) and β2 receptors (bronchodilation, reverses bronchospasm). The 1:1,000 concentration is used IM. Note: 1:10,000 is the IV concentration used in cardiac arrest.
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