A nurse is caring for a client who is receiving ondansetron IV. Which of the following findings is an indication that the ondansetron is effective?

The correct answer is D: Decreased nausea. Ondansetron is an antiemetic medication used to treat nausea and vomiting. Therefore, a decrease in nausea indicates the effectiveness of ondansetron. Absence of peripheral neuropathy (A) is not directly related to the action of ondansetron. Increased urinary output (B) is not a common effect of ondansetron. Reduced dizziness (C) may not necessarily indicate the effectiveness of ondansetron specifically for nausea. Therefore, the best indicator of ondansetron's effectiveness in this scenario is a decrease in nausea.