What is the antidote for Heparin?

Protamine sulfate is the antidote for heparin because it works by neutralizing the anticoagulant effects of heparin in the bloodstream. Heparin exerts its anticoagulant effect by activating antithrombin III, which inhibits thrombin and factor Xa, ultimately reducing the formation of fibrin clots. When there is a need to reverse this effect—such as in the case of excessive bleeding or a planned surgical procedure—protamine sulfate can be administered. It binds to heparin to form a stable complex, rendering it inactive.

The other options are related to different medications and situations: Vitamin K is an antidote for warfarin, Flumazenil is used to reverse benzodiazepine sedation, and Naloxone counteracts opioid overdose. Each of these is specific to its respective anticoagulant or substance and does not have an effect on heparin's action.