A 65-year-old patient with pneumonia is receiving Gentamicin. It would be most important for a nurse to monitor which of the following laboratory values in this patient?

1. A

   Hemoglobin and hematocrit

2. B

   Blood urea nitrogen and creatinine

3. C

   Platelet count and clotting time

4. D

   Sodium and potassium

Appeared in: GMCH Chandigarh - 2019

Explanation

• Gentamicin is an aminoglycoside antibiotic, a class of drugs known for causing significant nephrotoxicity (kidney damage) and ototoxicity (damage to the ear and hearing).
• Blood Urea Nitrogen (BUN) and serum creatinine are the most direct and sensitive laboratory indicators of renal function.
• An increase in BUN and creatinine levels is an early sign that the drug is affecting the kidneys, allowing for timely intervention to prevent irreversible damage.
• Older adult patients, like the 65-year-old in the scenario, are at a higher risk for developing nephrotoxicity, making vigilant monitoring essential.

Why Other Options Were Wrong

• Option A: Gentamicin does not directly affect red blood cell production or volume. Monitoring hemoglobin and hematocrit is not a priority for detecting this drug's specific toxicities.
• Option C: Gentamicin does not have a significant effect on platelets or the body's clotting cascade. This monitoring is not standard for aminoglycoside therapy.
• Option D: While electrolyte imbalances (especially of potassium and magnesium) can occur with aminoglycoside-induced kidney damage, they are typically later signs. BUN and creatinine are earlier and more direct indicators of nephrotoxicity.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Monitoring for Adverse Effects of Aminoglycosides to guide bedside assessment, documentation, and the next nursing action.
• Nurses must obtain baseline renal function tests (BUN, creatinine) before the first dose of Gentamicin and monitor these values throughout therapy, often daily or every 3 days.
• It is a critical patient safety intervention to promptly report any rise in creatinine or BUN, a decrease in urine output, or patient complaints of tinnitus (ringing in ears) or vertigo to the provider.
• Ensuring the patient is well-hydrated can help reduce the concentration of the drug in the kidneys, potentially lowering the risk of nephrotoxicity.

How to Approach the Question

• First, identify the key drug in the question: Gentamicin.
• Recall the drug's class and its major associated adverse effects. Gentamicin is an aminoglycoside, which is well-known for causing nephrotoxicity (kidney damage) and ototoxicity (ear damage).
• Analyze the options provided. Each option represents a different set of laboratory tests that monitor different body systems.
• Connect the drug's most common and serious adverse effect (nephrotoxicity) to the corresponding laboratory test. Kidney function is primarily measured by BUN and creatinine.
• Select the option that directly monitors for this primary toxicity, as this represents the most important nursing action in this context.

Concept Tested & Keywords

• Concept Tested: Monitoring for Adverse Effects of Aminoglycosides
• Stem keywords: Gentamicin, 65-year-old, pneumonia, monitor, laboratory values
• Lead-in keywords: most important
• Clinical cues: Drug administered (Gentamicin) is known for specific toxicities (nephrotoxicity, ototoxicity).
• Clinical cues: Patient age (65-year-old) increases the risk for drug-induced toxicity.

Question ID

Q4M9cCjy4wKloyh99XO_du

Copy ID

Reference Book

E6 Pharmacology Katzung 16e p. 1286-1288

E6 Pharmacology Nursing Lilley 11e Part 2 p. 316-318