Protamine

Protamine is an FDA-approved drug for use in neutralizing the effect of unfractionated heparin. It is most commonly used to neutralize heparin-induced anticoagulation after separation from cardiopulmonary bypass. When appropriately dosed, this neutralization reduces the risk of postoperative bleeding. Protamine is also utilized to reverse the anticoagulation effects of unfractionated heparin in the setting of dialysis, invasive vascular procedures, and acute ischemic strokes. Finally, clinicians can use protamine for a partial reversal of low molecular weight heparins including enoxaparin, dalteparin, and tinzaparin, but the degree of reversal is unclear, and this use has not been FDA-approved. Currently, protamine is produced using recombinant technology, but it was originally isolated from salmon fish sperm. When first introduced, protamine was used to prolong the action of insulin preparations; adding it to the preparation prolonged the duration of action of the insulin and delayed insulin absorption.