Which of the following is a known side effect after epinephrine administration in anaphylaxis?

• A. Hypotension
• B. Tachycardia
• C. Drowsiness
• D. Nausea

Answer: (B)

Tachycardia is the known side effect because epinephrine stimulates beta-1 receptors in the heart, which increases heart rate and the force of contraction. In anaphylaxis, epinephrine’s beta-1 action raises cardiac output, while its alpha-1–mediated vasoconstriction helps raise blood pressure and reduce airway swelling. This combination makes a faster pulse a common and expected response after administration.

Other options don’t fit as well. Hypotension is what epinephrine corrects in anaphylaxis, so an increased heart rate accompanies the treatment rather than being a side effect. Drowsiness isn’t typical for epinephrine and is not a characteristic effect of the drug’s action. Nausea can occur but is less common than tachycardia and not as hallmark as the rapid pulse produced by beta-1 stimulation.