use of protamine sulphate as an antidote to heparin

Last reviewed 01/2021

The effects of heparin can be reversed by protamine sulphate.

Approximately 1 mg of protamine sulphate neutralizes 100 iu of heparin. This dose can be calculated on this basis if protamine sulphate is given within 15 minutes of a single dose of heparin.

Protamine sulphate should not be administered in doses above 50 mg. It should be given slowly, intravenously, to avoid side effects such as hypotension, nausea, vomiting and flushing. Allergic reactions have been reported.