What is the antidote for heparin?

Protamine sulfate is the specific antidote for heparin, an anticoagulant medication. Heparin works by inhibiting thrombin and factor Xa, which are essential components of the blood coagulation cascade. When there is a need to reverse the effects of heparin, such as in cases of bleeding complications or prior to surgical procedures, protamine sulfate can be administered.

Protamine sulfate works by binding to heparin and forming a stable complex that neutralizes its anticoagulant effects. This rapid action makes it an effective choice in clinical settings where immediate reversal of heparin is required.

Other options provided do not serve as antidotes for heparin. For example, vitamin K is applicable for reversing the effects of vitamin K antagonists like warfarin. Calcium gluconate is associated with conditions like hypocalcemia or to stabilize cardiac tissue during hyperkalemia, but it does not play any role in heparin reversal. Similarly, amiodarone is an antiarrhythmic medication used to treat certain types of heart rhythm problems and is not relevant to the management of heparin toxicity. Thus, protamine sulfate stands out as the correct antidote in this context.