Which statement describes a disadvantage of ephedrine?

Which statement describes a disadvantage of ephedrine?

• A. Efficacy is reduced when norepinephrine stores are depleted
• B. Efficacy increases when norepinephrine stores are depleted
• C. It has no tachyphylaxis
• D. It never causes malignant hypertension

Answer: (A)

Ephedrine works in part by triggering the release of stored norepinephrine from sympathetic nerve endings. If those norepinephrine stores are depleted, there’s less NE available to be released, so its ability to raise blood pressure and produce the desired sympathetic effects is diminished. That makes this scenario a real disadvantage of ephedrine. Understanding this helps: ephedrine has both indirect and direct actions, so its effectiveness relies on intact NE stores. If stores are low, the indirect component can’t deliver as much NE, and the overall response wanes. It can also exhibit tachyphylaxis with continued use, and high doses can still provoke malignant hypertension, so claims that it never causes such hypertension aren’t accurate.

Ephedrine works in part by triggering the release of stored norepinephrine from sympathetic nerve endings. If those norepinephrine stores are depleted, there’s less NE available to be released, so its ability to raise blood pressure and produce the desired sympathetic effects is diminished. That makes this scenario a real disadvantage of ephedrine.

Understanding this helps: ephedrine has both indirect and direct actions, so its effectiveness relies on intact NE stores. If stores are low, the indirect component can’t deliver as much NE, and the overall response wanes. It can also exhibit tachyphylaxis with continued use, and high doses can still provoke malignant hypertension, so claims that it never causes such hypertension aren’t accurate.