Protamine sulfate is indicated for the rapid reversal of heparin anticoagulation, particularly after surgery, invasive procedures, or in cases of heparin overdose and bleeding. Its key advantage is a direct and immediate neutralization of heparin, forming a stable inactive complex and restoring normal coagulation. In operating rooms and ICU settings, protamine is essential following cardiopulmonary bypass, vascular surgery, and dialysis, where precise control of anticoagulation is critical. It allows clinicians to quickly reverse anticoagulant effects and reduce bleeding risk without delay. Its fast onset, predictable action, and targeted mechanism make protamine sulfate a vital and life-saving agent in acute care and surgical practice.