Meds that Affect Cardio in OD

Question 1

What are the meds that affect the coardiovascular system in an OD?

Answer 1

• Phenylpropanolamine
• Albuterol
• Beta Blockers
• Calcium Channel Blockers
• All of these can be life-threatening in an overdose!!

Question 2

What part of the nervous system do these drugs act on?

Answer 2

Autonomic with emphasis on sympathetic division

Question 3

What is the problem with treating tachycardia related to PPA-related NE release with a beta blocker?

Answer 3

You block B2 activated dilatation, leading to unopposed alpha stimulation and worsening Htn

Question 4

If one must use a beta blocker to treat PPA-related NE release tachycardia, what is the best drug to use?

Answer 4

Esmolol, a B1 specific antagonist (just lowers HR while not affecting B2 function)

Question 5

How do B2 agonists affect potassium?

Answer 5

Stimulate Na, K, ATPase pumps -> hypokalemia

Cause of hypophosphatemia less certain - may be due to similar mechanisms

Question 6

Why does an OD on B blockers cause hypotension?

Answer 6

B2 mediated decrease in chronotropy and inotropy -> decreased HR and BP; alpha effects (carvedilol) cannot override

Question 7

T/F: agonists typically bind receptors better than antagonists

Answer 7

False; antagonists typically bind receptors better than agonists