A patient is ordered a phenothiazine antiemetic for treatment of nausea and vomiting associated with chemotherapy. The nurse will be evaluating for a positive effect. At what time should the nurse administer the drug?

A. As requested by the patient. Administering the drug only when requested by the patient may not provide adequate prophylaxis against chemotherapy-induced nausea and vomiting. These medications are often prescribed on a schedule to prevent symptoms rather than treating them reactively. B. 1 hour after chemotherapy administration. Waiting until 1 hour after chemotherapy administration may not cover the full period during which nausea and vomiting are likely to occur. The administration schedule for antiemetics is often more extended to provide better coverage. C. The night before the treatment, the day of the treatment, and for 24 hours after the treatment. This is the correct choice. Administering phenothiazine antiemetics according to this schedule helps ensure continuous coverage during the critical period when chemotherapy-induced nausea and vomiting are most likely to occur. D. The day of treatment. Administering the drug only on the day of treatment may not provide sufficient coverage for the entire duration when chemotherapy-induced nausea and vomiting can occur. Again, the schedule mentioned in option C is more comprehensive for prevention.