Correct Answer: A

Rationale: Before administering digoxin, it is essential to assess the client's heart rate as this medication directly affects cardiac function. Monitoring the heart rate helps identify if it is within the acceptable range for administering digoxin. A pulse rate below 60 beats per minute warrants withholding the medication to prevent potential adverse effects like bradycardia or cardiac arrhythmias.

Correct Answer: D

Rationale: Ticlopidine hydrochloride is a platelet aggregation inhibitor. Aspirin or any aspirin-containing product should be avoided as they can precipitate or aggravate bleeding by affecting platelet function and increasing the risk of bleeding complications.

Correct Answer: D

Rationale: Pulmonary reactions such as cough and chest pain are serious side effects associated with nitrofurantoin that require immediate discontinuation of the medication to prevent potential severe respiratory complications.

Correct Answer: A

Rationale: Cisplatin, a chemotherapy medication, can lead to various adverse effects, including ototoxicity manifesting as tinnitus, hypokalemia, hypocalcemia, hypomagnesemia, and nephrotoxicity. Therefore, the nurse should closely monitor for these side effects during the client's treatment.

Correct Answer: B

Rationale: Clients using transdermal fentanyl (Duragesic) patches should avoid using heating pads over the patch as heat can increase the release of the medication, potentially leading to overdose. The patch should be applied to a different site each time, changed every 72 hours, and the old patch should be removed before applying a new one to prevent accidental overdose or excessive drug absorption.