Correct Answer: A

Rationale: The correct answer is A because warfarin takes several days to reach a therapeutic level and exert its full anticoagulant effect. During this time, the IV heparin is continued to prevent clotting until the warfarin is effective. Both medications are used together temporarily for this reason. Discontinuing heparin prematurely can increase the risk of clot formation. Therefore, the nurse should explain to the client that the IV heparin will be continued until the warfarin reaches a therapeutic level.

Correct Answer: B

Rationale: The nurse should obtain the blood sample for the peak serum level at 1030. This timing allows for 30 minutes to elapse after the completion of the 1-hour IV infusion, which is the recommended window for obtaining the peak serum level of gentamicin.

Correct Answer: A

Rationale: Ranitidine can potentially lead to blood dyscrasias, necessitating the monitoring of the client's CBC. Checking the CBC can help detect any abnormalities in blood cell counts and assess the client's overall hematologic status during Ranitidine therapy.

Correct Answer: D

Rationale: Metformin exerts its effects by decreasing hepatic glucose production, increasing sensitivity to insulin, and decreasing intestinal glucose absorption. These actions help in lowering blood glucose levels and improving insulin sensitivity in individuals with diabetes.

Correct Answer: A

Rationale: The correct answer is A because warfarin takes several days to reach a therapeutic level and exert its full anticoagulant effect. During this time, the IV heparin is continued to prevent clotting until the warfarin is effective. Both medications are used together temporarily for this reason. Discontinuing heparin prematurely can increase the risk of clot formation. Therefore, the nurse should explain to the client that the IV heparin will be continued until the warfarin reaches a therapeutic level.