A patient with a diagnosis of pulmonary embolism is placed on a heparin drip. The nurse should have which of the following drugs available in cases of accidental overdose?

A. Calcium gluconate: Calcium gluconate is used to treat conditions such as hyperkalemia or calcium channel blocker overdose. It has no role in reversing the anticoagulant effects of heparin and would not be useful in this scenario. B. Vitamin K: Vitamin K is the antidote for warfarin (Coumadin), not heparin. It promotes the synthesis of clotting factors inhibited by warfarin but does not affect the mechanism of action of heparin. C. Protamine sulfate: Protamine sulfate binds to heparin and neutralizes its anticoagulant effect, making it the specific antidote for heparin overdose. It is used to reverse excessive anticoagulation and reduce the risk of bleeding complications. D. Potassium chloride: Potassium chloride is used to treat or prevent hypokalemia. It has no antidotal properties for anticoagulants and would not be relevant in managing heparin toxicity.