A nurse is caring for a client who is taking azathioprine to treat rheumatoid arthritis. Which of the following laboratory values indicates an adverse effect of this medication?

Choice A Reason:
Levothyroxine 100 mcg PO every morning is incorrect. Indicates the dosage (100 mcg) and the route (by mouth) to be taken every morning.
Choice B Reason:
Simvastatin 40 mg PO at bedtime: Specifies the dosage (40 mg) and the timing (at bedtime) for administration.
Choice C Reason:
Acetaminophen 500 mg every 4 hr RN for fever is correct. The term "RN" in this context might be interpreted as "right now" rather than the intended meaning, which could cause confusion regarding the frequency of acetaminophen administration. The nurse should seek clarification to ensure accurate and safe dosing instructions.
Choice D Reason:
Morphine 4 mg IV every 4 hr PRN for pain: Specifies the dosage (4 mg), the route (intravenous), and the frequency (every 4 hours as needed) for pain management.

Choice A Reason:
BUN 15 mg/dL (blood urea nitrogen) is incorrect. An elevated BUN level can indicate kidney dysfunction or dehydration, but it's not typically associated with azathioprine's adverse effects. Azathioprine is known to affect bone marrow, leading to decreased blood cell counts, rather than directly impacting kidney function.
Choice B Reason:
WBC 3,000/mm³ (low white blood cell count) is correct. Azathioprine is an immunosuppressive medication used to treat various conditions, including rheumatoid arthritis. One of its known adverse effects is bone marrow suppression, which can lead to decreased production of blood cells, including white blood cells (WBCs). A low WBC count (leukopenia) can increase the risk of infections due to compromised immune function, making it an important adverse effect to monitor in individuals taking azathioprine.
Choice C Reason:
Hct 45% (hematocrit) is incorrect. A hematocrit of 45% is within the normal range for both men and women. Azathioprine adverse effects usually manifest as blood cell-related issues (such as leukopenia) rather than directly impacting hematocrit levels.
Choice D Reason:
Platelets 250,000/mm³: Platelets within the range of 150,000 to 400,000/mm³ are considered normal. Azathioprine typically affects white blood cells more prominently than platelet counts.