Correct Answer: B

Rationale: Drowsiness can be a sign of water intoxication or hyponatremia, which are potential adverse effects of desmopressin acetate (DDAVP). It is crucial to monitor for this symptom and promptly address it to prevent complications.

Correct Answer: D

Rationale: Persistent vomiting can be a sign of lithium toxicity, which requires immediate medical attention. Increased thirst, fine hand tremors, and frequent urination are common side effects of lithium.

Correct Answer: C

Rationale: The activated partial thromboplastin time (aPTT) is the specific laboratory test used to monitor the effectiveness of heparin therapy in patients with deep vein thrombosis. It measures the time it takes for blood to clot and is crucial in assessing the therapeutic range of heparin. Platelet count, prothrombin time (PT), and hemoglobin and hematocrit levels are important parameters in assessing coagulation and blood status but do not directly indicate the effectiveness of heparin therapy.

Correct Answer: B

Rationale: The axilla has thinner skin, making it more permeable to topical medications. Areas with thinner skin, like the axilla, allow for higher systemic absorption of topical corticosteroids.

Correct Answer: A

Rationale: To assess the effectiveness of leflunomide (Arava), a medication used to treat rheumatoid arthritis, the nurse should inquire about joint pain. Joint pain is a common symptom of rheumatoid arthritis, and improvement in joint pain indicates the medication's effectiveness in managing the condition.