A patient with atrial fibrillation is prescribed warfarin. Which laboratory test should the nurse monitor to assess the effectiveness of the medication?

Correct Answer: B

Rationale: The correct answer is B: Prothrombin time (PT)/INR. This is because warfarin is a medication that affects the clotting ability of the blood by inhibiting vitamin K-dependent clotting factors. PT/INR is the specific laboratory test used to monitor the effectiveness of warfarin therapy. PT measures how long it takes for blood to clot, while INR standardizes the PT results. Monitoring PT/INR helps to ensure that the patient is within the target therapeutic range for anticoagulation. Incorrect choices: A: Complete blood count (CBC) - CBC does not directly assess the effectiveness of warfarin therapy. C: Partial thromboplastin time (PTT) - PTT is used to monitor the effectiveness of heparin therapy, not warfarin. D: Serum potassium level - Monitoring serum potassium level is not directly related to assessing the effectiveness of warfarin therapy.

Correct Answer: C

Rationale: Insulin glargine is a long-acting insulin due to its slow and consistent release, providing basal insulin coverage for about 24 hours. This steady release mimics the body's natural basal insulin secretion pattern. Rapid-acting insulins (A) work quickly to control postprandial glucose levels. Intermediate-acting insulins (B) have a slower onset and last for a moderate duration. Short-acting insulins (D) act quickly but have a shorter duration of action compared to long-acting insulins.

Correct Answer: B

Rationale: The primary purpose of prescribing calcium acetate for a patient with CKD is to reduce phosphate levels. Calcium acetate acts as a phosphate binder, preventing the absorption of dietary phosphate in the intestines. Elevated phosphate levels in CKD can lead to complications such as mineral and bone disorders. Treating hyperkalemia (A) involves other medications like potassium binders, not calcium acetate. Lowering blood pressure (C) typically involves antihypertensive drugs. Increasing hemoglobin levels (D) is usually managed with erythropoiesis-stimulating agents in CKD patients. Therefore, option B is the correct answer for the primary purpose of prescribing calcium acetate in CKD patients.

Correct Answer: B

Rationale: The correct answer is B: Change the patch every 72 hours. Fentanyl patches are typically designed to be worn for 72 hours before being replaced to maintain consistent pain relief. Changing the patch on time helps prevent withdrawal symptoms and ensures the effectiveness of the medication. A: Applying the patch to a different site each time is important to prevent skin irritation but is not the most crucial instruction. C: Avoiding heating pads over the patch is important to prevent overheating and excessive absorption of the medication, but changing the patch timely is more critical. D: Removing the patch before showering is not necessary as fentanyl patches are designed to be water-resistant.

Correct Answer: A

Rationale: The primary advantage of prescribing rivaroxaban over warfarin for a patient with a history of DVT is the absence of regular INR monitoring required with rivaroxaban. This is because rivaroxaban is a direct oral anticoagulant with more predictable pharmacokinetics, eliminating the need for monitoring. Regular INR monitoring is necessary with warfarin to ensure the drug is within the therapeutic range, which can be burdensome for patients and healthcare providers. The other choices are incorrect as they do not directly address the primary advantage of rivaroxaban over warfarin for this specific patient population.