is a drug that reverses the anticoagulant
effects of heparin
by binding to it.
Protamine was formerly isolated from the sperm of various fish, but is now produced through recombinant biotechnology. It is a highly cationic peptide. It binds to heparin to form a stable ion pair which does not have anticoagulant activity. This complex is then removed and broken down by the reticuloendothelial system.
Dosage for heparin reversal is 1mg protamine sulfate i.v. for every 100 IU of active heparin. In patients who are allergic to fish, it can cause significant histamine
release resulting in hypotension
, and also causes pulmonary hypertension
. Infusion should be slow to minimize these side effects. In large doses, protamine itself has some anticoagulant effect.
Protamine sulfate is usually administered to reverse the large dose of heparin administered during certain surgeries, especially heart surgery
. It is also used in gene transfer and protein purification.