Between epinephrine and ephedrine, which has greater bronchodilating effects due to beta-2 activation?

Between epinephrine and ephedrine, which has greater bronchodilating effects due to beta-2 activation?

• A. Epinephrine
• B. Ephedrine
• C. Both equal
• D. Neither

Answer: (A)

Bronchodilation mainly comes from activating beta-2 receptors on airway smooth muscle. Epinephrine is a direct and indirect adrenergic agonist with strong beta-2 activity, so it produces robust bronchodilation. Ephedrine is a mixed-acting sympathomimetic that increases norepinephrine release and stimulates receptors, but its beta-2 effects are weaker and less direct, leading to a smaller bronchodilating response. So, epinephrine provides greater bronchodilation due to its more potent beta-2 receptor activation.

Bronchodilation mainly comes from activating beta-2 receptors on airway smooth muscle. Epinephrine is a direct and indirect adrenergic agonist with strong beta-2 activity, so it produces robust bronchodilation. Ephedrine is a mixed-acting sympathomimetic that increases norepinephrine release and stimulates receptors, but its beta-2 effects are weaker and less direct, leading to a smaller bronchodilating response. So, epinephrine provides greater bronchodilation due to its more potent beta-2 receptor activation.