Levonordefrin potency relative to epinephrine is 1/6.

Levonordefrin potency relative to epinephrine is 1/6.

• A. True
• B. False
• C. More potent
• D. Equally potent

Answer: (A)

Potency describes how much drug is needed to produce a given effect. Levonordefrin is about one-sixth as potent as epinephrine as a vasoconstrictor, meaning you need more levonordefrin to achieve the same vasoconstrictive effect that epinephrine provides. Clinically, this is reflected in the typical concentrations used: levonordefrin is given as 1:20,000 while epinephrine is often 1:100,000. The higher concentration of levonordefrin is offset by its lower intrinsic potency, so the overall vasoconstrictive effect ends up similar when dosed appropriately. Epinephrine also has strong beta-adrenergic effects that levonordefrin lacks, contributing to a different systemic profile, but for vasoconstriction alone the relative potency is about sixfold in favor of epinephrine. Therefore, the statement that levonordefrin’s potency relative to epinephrine is 1/6 is correct.

Potency describes how much drug is needed to produce a given effect. Levonordefrin is about one-sixth as potent as epinephrine as a vasoconstrictor, meaning you need more levonordefrin to achieve the same vasoconstrictive effect that epinephrine provides. Clinically, this is reflected in the typical concentrations used: levonordefrin is given as 1:20,000 while epinephrine is often 1:100,000. The higher concentration of levonordefrin is offset by its lower intrinsic potency, so the overall vasoconstrictive effect ends up similar when dosed appropriately. Epinephrine also has strong beta-adrenergic effects that levonordefrin lacks, contributing to a different systemic profile, but for vasoconstriction alone the relative potency is about sixfold in favor of epinephrine. Therefore, the statement that levonordefrin’s potency relative to epinephrine is 1/6 is correct.