Correct Answer: D

Rationale: Crackles on auscultation of the lungs would indicate a toxic effect related to daunorubicin, known to cause cardiotoxicity. Cardiotoxicity can manifest as heart failure, abnormal ECG findings, or cardiomyopathy. It is crucial for the nurse to monitor for signs of cardiotoxicity to ensure timely intervention and prevent further complications.

Correct Answer: C

Rationale: Cetirizine hydrochloride (Zyrtec) is known to commonly cause drowsiness or sedation as a side effect. Therefore, the nurse should monitor the client for signs of drowsiness when administering this medication.

Correct Answer: D

Rationale: Meperidine hydrochloride (Demerol) is an opioid analgesic that can cause various side effects. Common side effects include respiratory depression, orthostatic hypotension, tachycardia, drowsiness, constipation, and urinary retention. Therefore, the nurse should monitor for urinary retention as a potential side effect of Meperidine hydrochloride.

Correct Answer: B

Rationale: The correct answer is B: Problems with visual acuity. Ethambutol is known to cause optic neuritis, leading to a decrease in visual acuity and color discrimination. Therefore, any visual changes should be reported promptly to prevent further complications.

Correct Answer: B

Rationale: The correct instruction for the nurse to include in the client's teaching plan when taking methotrexate is to report any signs of infection immediately. Methotrexate can suppress the immune system, making the client more susceptible to infections. It is important for the client to promptly report any signs of infection to receive timely medical intervention. Additionally, the client should actually take folic acid supplements to reduce side effects, take the medication on an empty stomach if tolerated, and maintain adequate fluid intake to prevent complications.