Patient at risk of developing hypersensitivity to protamine (e.g. previous history of procedures such as coronary angioplasty or cardiopulmonary bypass surgery where protamine is frequently used, diabetics using protamine insulin, allergy to fish, vasectomised or infertile males who may have antibodies to protamine). Pregnancy and lactation.
Protamine sulfate can cause severe hypotension, cardiovascular collapse, noncardiogenic pulmonary edema, catastrophic pulmonary vasoconstriction, and pulmonary hypertension