What is the B1 effect of ephedrine?

What is the B1 effect of ephedrine?

• A. Decrease heart rate and contractility
• B. No change in heart rate or contractility
• C. Increase heart rate only
• D. Increase heart rate and contractility

Answer: (D)

Beta-1 stimulation increases both heart rate (chronotropy) and contractility (inotropy). Ephedrine is a mixed-acting sympathomimetic that directly stimulates alpha and beta receptors and also increases norepinephrine release. The beta-1 effects raise heart rate and strengthen each beat by increasing cAMP in cardiac cells, which boosts calcium availability and conduction through the AV node as well. So the net B1 effect is to increase both heart rate and contractility. The other options don’t fit because beta-1 activation does not produce only one of those effects, nor no change, nor a decrease.

Beta-1 stimulation increases both heart rate (chronotropy) and contractility (inotropy). Ephedrine is a mixed-acting sympathomimetic that directly stimulates alpha and beta receptors and also increases norepinephrine release. The beta-1 effects raise heart rate and strengthen each beat by increasing cAMP in cardiac cells, which boosts calcium availability and conduction through the AV node as well. So the net B1 effect is to increase both heart rate and contractility. The other options don’t fit because beta-1 activation does not produce only one of those effects, nor no change, nor a decrease.