Pharmacology · single question
A patient goes into ANAPHYLAXIS in the dental office. What will you administer?
Show answer and explanation
Correct answer: B. Epinephrine 1:1,000 (IM)
Epinephrine 1:1,000 IM (B) is the FIRST-LINE treatment for anaphylaxis. Standard dosing:
• 0.3–0.5 mL of 1:1,000 epinephrine IM into the anterolateral thigh (vastus lateralis) — fastest absorption.
• Can repeat every 5-15 minutes if no response.
Why epinephrine works:
• α1 effect: vasoconstriction → reverses hypotension
• β1 effect: increases heart rate and contractility → reverses cardiac depression
• β2 effect: bronchodilation → reverses bronchospasm
• Reduces mast cell mediator release
• 1:10,000 (C): used for cardiac arrest (IV/IO route) — too dilute for anaphylaxis IM administration.
• Diphenhydramine (A): antihistamine — adjunct therapy (H1 blocker) but NOT first-line and too slow-acting for anaphylaxis.
• Epinephrine FIRST, then call 911, then antihistamines/corticosteroids.
• 0.3–0.5 mL of 1:1,000 epinephrine IM into the anterolateral thigh (vastus lateralis) — fastest absorption.
• Can repeat every 5-15 minutes if no response.
Why epinephrine works:
• α1 effect: vasoconstriction → reverses hypotension
• β1 effect: increases heart rate and contractility → reverses cardiac depression
• β2 effect: bronchodilation → reverses bronchospasm
• Reduces mast cell mediator release
• 1:10,000 (C): used for cardiac arrest (IV/IO route) — too dilute for anaphylaxis IM administration.
• Diphenhydramine (A): antihistamine — adjunct therapy (H1 blocker) but NOT first-line and too slow-acting for anaphylaxis.
• Epinephrine FIRST, then call 911, then antihistamines/corticosteroids.