A nurse is caring for a client who is receiving heparin therapy. If the client requires a reversal of the effects of heparin, which of the following medications should the nurse expect the provider to prescribe?

A. Atropine. Atropine is an anticholinergic medication used to treat bradycardia and reduce secretions before surgery. It has no effect on reversing anticoagulation caused by heparin and would not be an appropriate treatment for heparin overdose. B. Vitamin K. Vitamin K is used as an antidote for warfarin toxicity, as it helps produce clotting factors that warfarin inhibits. However, it does not reverse the effects of heparin, which works by enhancing the activity of antithrombin to prevent clot formation. C. Vitamin B12. Vitamin B12 is essential for red blood cell production and neurological function, primarily used to treat conditions like pernicious anemia. It does not have any role in reversing the anticoagulant effects of heparin and would not be beneficial in this situation. D. Protamine. Protamine sulfate is the specific antidote for heparin overdose. It binds to heparin, neutralizing its anticoagulant effects and preventing excessive bleeding. Protamine is administered intravenously in cases of heparin toxicity or when urgent reversal is needed, such as before surgery or in cases of uncontrolled bleeding.