A client who is taking an oral contraceptive receives a new prescription for erythromycin. Which instruction should the nurse provide to the client?

Choice A reason: Determining when the last dose was administered is important to ensure safe and effective pain management, but it is not the first action that the nurse should implement. The nurse should first assess the client's pain level and intensity before deciding on the appropriate dose and frequency of pain medication.

Choice B reason: Encouraging the client to use diversional thoughts to manage pain is a non-pharmacological intervention that can help reduce pain perception and anxiety, but it is not sufficient to address severe or acute pain. The nurse should first assess the client's pain level and intensity before suggesting any complementary or alternative therapies.

Choice C reason: Asking the client to rate the current level of pain using a pain scale is the first action that the nurse should implement, as it can help quantify and communicate the client's pain experience and guide the nurse's decision on pain medication. The nurse should use a valid and reliable pain scale that is appropriate for the client's age, cognitive ability, and language preference.

Choice D reason: Reviewing the history for a past use of recreational drugs is relevant to assess the client's risk of addiction or tolerance to pain medication, but it is not the first action that the nurse should implement. The nurse should first assess the client's pain level and intensity before considering any factors that may influence pain management.

Choice A reason: This is the best option to measure the peak and trough levels of vancomycin, as it reflects the highest and lowest concentrations of the drug in the blood. The peak level indicates the efficacy and potential toxicity of vancomycin, while the trough level indicates the clearance and potential subtherapeutic effect of vancomycin. The peak level should be drawn immediately after completion of the IV dose, as it takes about 30 minutes for vancomycin to reach its maximum concentration in the blood. The trough level should be drawn 30 minutes before the next administration of the medication, as it represents the lowest concentration of vancomycin in the blood before it is replenished by another dose.

Choice B reason: This is not a good option to measure the peak and trough levels of vancomycin, as it may not capture the true highest and lowest concentrations of the drug in the blood. The peak level may be lower than expected, as it takes about 30 minutes for vancomycin to reach its maximum concentration in the blood. The trough level may be higher than expected, as it is drawn too close to the next administration of the medication.

Choice C reason: This is not a good option to measure the peak and trough levels of vancomycin, as it does not reflect the highest and lowest concentrations of the drug in the blood. The peak level is drawn too early, as vancomycin has not reached its maximum concentration in the blood yet. The trough level is drawn too late, as vancomycin has already started to decline in the blood.

Choice D reason: This is not a good option to measure the peak and trough levels of vancomycin, as it may miss the highest and lowest concentrations of the drug in the blood. The peak level is drawn too late, as vancomycin may have already started to decline in the blood. The trough level is drawn too early, as vancomycin may have not reached its minimum concentration in the blood yet.