Cardio Pharm Question

[DocMiami]

1. Mr Green, a 54-year-old banker, had a cardiac transplant 6 months ago. His current blood pressure is 120/70 mm Hg and heart rate is 100 bpm. Which of the following drugs would have the least effect on Mr Green's heart rate?

(A)Albuterol

(B)Epinephrine

(C)Isoproterenol

(D)Norepinephrine

(E)Phenylephrine

Answer : E

Could someone please explain why E is correct? Thank you
Wouldn't you get reflex bradycardia w/ Phenylephrine?

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[DocMiami]

1. Which of the following drugs most resembles drug X?

(A)Atropine

(B)Bethanechol

(C)Epinephrine

(D)Isoproterenol

(E)Phenylephrine

1. Which of the following most resembles drug Y?

(A)Atropine

(B)Bethanechol

(C)Epinephrine

(D)Isoproterenol

(E)Phenylephrine*

 

[DocMiami]

This one also ! Thank you

 

[chromuffin]

1. Mr Green, a 54-year-old banker, had a cardiac transplant 6 months ago. His current blood pressure is 120/70 mm Hg and heart rate is 100 bpm. Which of the following drugs would have the least effect on Mr Green's heart rate?

(A)Albuterol

(B)Epinephrine

(C)Isoproterenol

(D)Norepinephrine

(E)Phenylephrine

Answer : E

Could someone please explain why E is correct? Thank you
Wouldn't you get reflex bradycardia w/ Phenylephrine?

I believe the idea here is that every other drug has beta-1 agonist properties. So all the other drugs will cause cardiac stimulation (increased chronotropy) whereas PE acts at alpha-1 and can only vasoconstrict and INDIRECTLY affect HR via baroreceptor reflex.

 

[chromuffin]

View attachment 214530

1. Which of the following drugs most resembles drug X?

(A)Atropine

(B)Bethanechol

(C)Epinephrine

(D)Isoproterenol

(E)Phenylephrine

1. Which of the following most resembles drug Y?

(A)Atropine

(B)Bethanechol

(C)Epinephrine

(D)Isoproterenol

(E)Phenylephrine*

For the first question, I would think the answer is isoproterenol because it is the only drug that vasodilates (beta-2) without alpha activity (like epi).

For the second question, I think it is because PE is the only drug that vasoconstricts without vasodilation get (as the case with epinephrine). So I would think epinephrine would increase systolic but keep diastolic flat.

I could be wrong on these though. But that is my thought process.

 

[DocMiami]

For the first question, I would think the answer is isoproterenol because it is the only drug that vasodilates (beta-2) without alpha activity (like epi).

For the second question, I think it is because PE is the only drug that vasoconstricts without vasodilation get (as the case with epinephrine). So I would think epinephrine would increase systolic but keep diastolic flat.

I could be wrong on these though. But that is my thought process.

Thank you very much. Appreciate it.

 

[DocMiami]

For the first question, I would think the answer is isoproterenol because it is the only drug that vasodilates (beta-2) without alpha activity (like epi).

For the second question, I think it is because PE is the only drug that vasoconstricts without vasodilation get (as the case with epinephrine). So I would think epinephrine would increase systolic but keep diastolic flat.

I could be wrong on these though. But that is my thought process.

For the 1st question. Doesn't isoproterenol cause an increase in systolic bp via beta 1 ? Since its showing no change in SBP it threw me off.

 

[chromuffin]

For the 1st question. Doesn't isoproterenol cause an increase in systolic bp via beta 1 ? Since its showing no change in SBP it threw me off.

Isoproterenol acts at beta-1 and beta-2. The effects of beta-2 cause vasodilation, right? Which would reduce diastolic filling (lower BP). However, the beta-1 effects will increase HR. But an increased HR has no direct effect on systolic pressure, rather systolic pressure has an effect on HR. Make sense?

Edit: beta-1 does increase renin release which could affect BP long term but I think this question is really addressing more of the baroreceptor reflex and what it does.

 

[BurghStudent]

1. Mr Green, a 54-year-old banker, had a cardiac transplant 6 months ago. His current blood pressure is 120/70 mm Hg and heart rate is 100 bpm. Which of the following drugs would have the least effect on Mr Green's heart rate?

(A)Albuterol

(B)Epinephrine

(C)Isoproterenol

(D)Norepinephrine

(E)Phenylephrine

Answer : E

Could someone please explain why E is correct? Thank you
Wouldn't you get reflex bradycardia w/ Phenylephrine?

Isn't the point here that in any situation, phenylephrine can cause reflex bradycardia. However, with a transplanted heart, and vagus denervation, this reflex bradycardia couldn't occur. All the other drugs have some level of direct activity on the heart.