What potential side effect should a nurse be most concerned about in a client taking isoniazid and rifampin for tuberculosis?

• A. Blurred vision
• B. Yellowish sclera
• C. Nausea and vomiting
• D. Decreased urine output

Answer: (B)

The concern regarding yellowish sclera in a client taking isoniazid and rifampin primarily relates to the potential for liver toxicity, which is a significant side effect of both medications. Isoniazid and rifampin are known to have hepatotoxic effects, and jaundice can be an indication of liver damage. When the sclera of the eyes appears yellow, it is a classic sign of jaundice, often stemming from elevated bilirubin levels due to impaired liver function. Monitoring liver function through regular assessments is essential in patients on these medications, as early detection of hepatotoxicity can prevent serious complications.

While blurred vision, nausea and vomiting, and decreased urine output may occur with various medications, they are not as specifically associated with isoniazid and rifampin as jaundice is. Thus, yellowish sclera serves as a critical indicator for nurses to evaluate and act upon in order to ensure patient safety and manage any potential adverse effects effectively.