The nurse would need to monitor the serum glucose levels of a client receiving which of the following medications, owing to its effects on glycogenolysis and insulin release?

1. A

   Norepinephrine (Levophed)

2. B

   Dobutamine (Dobutrex)

3. C

   Propranolol (Inderal)

4. D

   Epinephrine (Adrenalin)

Appeared in: NORCET 5 mains

Explanation

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• Epinephrine is a non-selective adrenergic agonist, stimulating alpha-1, alpha-2, beta-1, and beta-2 receptors.
• Stimulation of beta-2 receptors in the liver promotes glycogenolysis (the breakdown of glycogen to glucose), releasing glucose into the bloodstream.
• Stimulation of alpha-2 receptors in the pancreas inhibits insulin secretion, preventing cells from taking up glucose and further elevating blood glucose levels.
• This dual mechanism leads to a significant and rapid increase in serum glucose, known as hyperglycemia, necessitating close monitoring.

Why Other Options Were Wrong

• Option A: Norepinephrine primarily stimulates alpha-1 and beta-1 receptors. It has weak activity at beta-2 receptors, so its effect on glycogenolysis and blood glucose is much less pronounced than that of epinephrine.
• Option B: Dobutamine is a selective beta-1 adrenergic agonist. Its primary site of action is the heart, where it increases contractility and cardiac output. It has minimal to no effect on beta-2 or alpha receptors involved in glucose regulation.
• Option C: Propranolol is a non-selective beta-blocker. It has the opposite effect of what the question describes. By blocking beta-2 receptors, it can inhibit glycogenolysis, which increases the risk of hypoglycemia, especially in diabetic patients. It can also mask the adrenergic symptoms of hypoglycemia (like tremors and tachycardia).

Related Visual

• Visual 1: Diagram: A flowchart illustrating how Epinephrine stimulates both hepatic glycogenolysis (via beta-2 receptors) and inhibits pancreatic insulin release (via alpha-2 receptors), leading to hyperglycemia.
• Visual 2: Infographic: A comparison table showing the receptor selectivity (Alpha-1, Alpha-2, Beta-1, Beta-2) and primary clinical effects of Epinephrine, Norepinephrine, Dobutamine, and Propranolol.

Clinical Relevance

• Nursing practice connection: Use the key finding related to Pharmacological effects of adrenergic agents on glucose metabolism to guide bedside assessment, documentation, and the next nursing action.
• Nurses must be vigilant in monitoring blood glucose levels in any patient receiving epinephrine, especially via continuous infusion.
• Patients with pre-existing diabetes mellitus are at a particularly high risk for severe hyperglycemia and may require adjustments to their insulin therapy.
• What if the patient is diabetic and also taking a beta-blocker like propranolol? The administration of epinephrine could still cause hyperglycemia, but if the patient later develops hypoglycemia (e.g., from an insulin dose), the beta-blocker will mask the early warning signs, increasing the risk of a severe hypoglycemic event. This creates a complex and high-risk monitoring situation.

How to Approach the Question

• First, identify the core physiological processes in the question: 'glycogenolysis' (breakdown of glycogen to glucose) and 'insulin release'. The question is asking which drug promotes the former and inhibits the latter, both leading to higher blood sugar.
• Next, classify each medication option based on its mechanism of action (e.g., adrenergic agonist/antagonist, receptor selectivity).
• Recall or look up the specific receptor effects of each drug. Epinephrine is a non-selective agonist (alpha and beta). Propranolol is a non-selective antagonist. Norepinephrine is mostly alpha/beta-1. Dobutamine is mostly beta-1.
• Connect the receptor effects to glucose metabolism: Beta-2 agonism stimulates glycogenolysis. Alpha-2 agonism inhibits insulin release.
• Evaluate each option: Epinephrine stimulates both receptor types. The other options either lack the necessary receptor activity (Norepinephrine, Dobutamine) or have the opposite effect (Propranolol).
• Conclude that Epinephrine is the only option that fits both criteria described in the question stem.

Concept Tested & Keywords

• Concept Tested: Pharmacological effects of adrenergic agents on glucose metabolism.
• Stem keywords: serum glucose levels, monitor, glycogenolysis, insulin release
• Lead-in keywords: which of the following

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