Correct Answer: D

Rationale: The activated partial thromboplastin time (aPTT) is used to monitor the therapeutic effect of heparin sodium. Heparin affects the intrinsic pathway of coagulation, and monitoring aPTT helps ensure the medication is within the therapeutic range to prevent clot formation. Hematocrit and hemoglobin levels assess red blood cell concentrations, while prothrombin time (PT) is used to monitor the therapeutic effect of warfarin sodium, a different anticoagulant that affects the extrinsic pathway of coagulation.

Correct Answer: B

Rationale: Spinach is high in vitamin K, which antagonizes the effects of warfarin sodium, an anticoagulant medication. Therefore, clients taking warfarin should avoid consuming foods rich in vitamin K, like spinach, to maintain the medication's effectiveness.

Correct Answer: C

Rationale: Antineoplastic medications can lower the body's resistance, making it crucial for clients to consult with healthcare providers (HCPs) before receiving immunizations. This precaution helps to prevent potential complications that may arise due to the medication's impact on the immune system.

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: A

Rationale: The correct instruction for a client prescribed allopurinol (Zyloprim) for chronic gout is to take the medication with a full glass of water. This helps prevent kidney stones which can be a side effect of the medication. It is important for the client to avoid purine-rich foods to help manage gout symptoms. They should continue taking the medication even during a gout attack as prescribed by the healthcare provider. Allopurinol can be taken with or without food, so there is no need to take it on an empty stomach.