Which lab test is crucial for monitoring long-term phenytoin treatment?

Which lab test is crucial for monitoring long-term phenytoin treatment?

• A. Lipid panel
• B. Complete blood count
• C. Thyroid stimulating hormone
• D. PT/INR

Answer: (B)

Monitoring long-term phenytoin treatment is essential due to the potential for adverse effects that can impact various blood components. A complete blood count (CBC) is crucial in this setting because phenytoin can lead to hematological side effects such as leukopenia, thrombocytopenia, and anemia. Regular surveillance of the blood cell counts allows for early detection of these adverse effects, facilitating timely management to prevent serious complications. In the context of the other options, while testing lipid panels can be important for other medications and conditions, it does not have a specific relationship with phenytoin. Thyroid-stimulating hormone (TSH) levels are not directly affected by phenytoin, and monitoring PT/INR is generally related to anticoagulation therapy rather than the direct effects of phenytoin. Therefore, the CBC is the most relevant test for ongoing management and safety monitoring in patients treated with phenytoin.

Monitoring long-term phenytoin treatment is essential due to the potential for adverse effects that can impact various blood components. A complete blood count (CBC) is crucial in this setting because phenytoin can lead to hematological side effects such as leukopenia, thrombocytopenia, and anemia. Regular surveillance of the blood cell counts allows for early detection of these adverse effects, facilitating timely management to prevent serious complications.

In the context of the other options, while testing lipid panels can be important for other medications and conditions, it does not have a specific relationship with phenytoin. Thyroid-stimulating hormone (TSH) levels are not directly affected by phenytoin, and monitoring PT/INR is generally related to anticoagulation therapy rather than the direct effects of phenytoin. Therefore, the CBC is the most relevant test for ongoing management and safety monitoring in patients treated with phenytoin.