WARNING Protamine sulfate can cause severe hypotension, cardiovascular collapse, noncardiogenic pulmonary edema, catastrophic pulmonary vasoconstriction, and pulmonary hypertension. Risk factors include high dose or overdose, rapid administration (see WARNINGS and DOSAGE AND ADMINISTRATION ), repeated doses, previous administration of protamine, and current or previous use of protamine-containing drugs (NPH insulin, protamine zinc insulin, and certain beta-blockers). Allergy to fish, previous vasectomy, and severe left ventricular dysfunction and abnormal preoperative pulmonary hemodynamics also may be risk factors. In patients with any of these risk factors, the risk to benefit of administration of protamine sulfate should be carefully considered. Vasopressors and resuscitation equipment should be immediately available in case of a severe reaction to protamine. Protamine sulfate should not be given when bleeding occurs without prior heparin use.
Adult Dosing
General dosing
: Each mg of protamine sulfate, calculated on the dried basis, neutralizes not less than 100 USP Heparin Units. Protamine sulfate injection should be given by very slow intravenous injection over a 10-minute period in doses not to exceed 50 mg (see WARNINGS ). Protamine sulfate is intended for injection without further dilution; however, if further dilution is desired, D5-W or normal saline may be used. Diluted solutions should not be stored since they contain no preservative. Protamine sulfate should not be mixed with other drugs without knowledge of their compatibility, because protamine sulfate has been shown to be incompatible with certain antibiotics, including several of the cephalosporins and penicillins. Because heparin disappears rapidly from the circulation, the dose of protamine sulfate required also decreases rapidly with the time elapsed following intravenous injection of heparin. For example, if the protamine sulfate is administered 30 minutes after the heparin, one-half the usual dose may be sufficient. The dosage of protamine sulfate should be guided by blood coagulation studies (see WARNINGS ).
Max: 50 mg (see WARNINGS )
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