Last updated on RxList: 6/28/2021

Drug Summary

What Is Protamine?

Protamine Sulfate (protamines) is a heparin antagonist and a weak anticoagulant indicated in the treatment of heparin (a drug used to treat and prevent blood clots) overdose.

What Are Side Effects of Protamine?

Common side effects of Protamine Sulfate include:

There have been reports of severe allergic reaction (anaphylaxis) after using Protamine Sulfate that resulted in respiratory difficulty, systemic high blood pressure (hypertension), nausea, vomiting, fatigue, and back pain.

Dosage for Protamine

Protamine Sulfate is administered by a doctor and is given by very slow intravenous (IV) injection in doses not to exceed 50 mg in any 10-minute period.

What Drugs, Substances, or Supplements Interact with Protamine?

Protamine sulfate may interact with certain antibiotics, including several of the cephalosporins and penicillins. Tell your doctor all medications you are taking.

Protamine During Pregnancy or Breastfeeding

Protamine sulfate should be given to a pregnant woman only if prescribed. It is not known whether this drug passes into breast milk. Consult a doctor before breastfeeding.

Additional Information

Our Protamine Sulfate (protamines) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

Drug Description


Protamine Sulfate Injection, USP is a sterile, non-pyrogenic, isotonic solution of protamine sulfate in Water for Injection. It acts as a heparin antagonist. It is also a weak anticoagulant.

Protamines are simple protein principles obtained from the sperm of salmon and certain other species of fish. Protamine (protamines) s have low molecular weight, are rich in arginine, and are strongly basic.

Protamine sulfate (protamine (protamines) s) occurs as fine white or off-white amorphous or crystalline powder. It is sparingly soluble in water. The pH is between 6 and 7. The cationic hydrogenated protamine at a pH of 6.8 to 7.1 reacts with anionic heparin at a pH of 5.0 to 7.5 to form an inactive complex.

Each mL contains

Protamine sulfate 10 mg, sodium chloride 9 mg and Water for Injection q.s. Sulfuric acid and/or dibasic sodium phosphate (heptahydrate) may have been added for pH adjustment.

The preparation is preservative free.

Protamine sulfate is administered intravenously.

Indications & Dosage


Protamine Sulfate (protamine (protamines) s) Injection, USP is indicated in the treatment of heparin overdosage.


Each mg of protamine sulfate (protamine (protamines) s) will neutralize approximately 90 USP units of heparin activity derived from beef lung tissue or about 115 USP units of heparin activity derived from porcine intestinal mucosa.

Protamine Sulfate (protamine (protamines) s) Injection,USP should be given by very slow intravenous injection in doses not to exceed 50 mg of protamine sulfate (protamine (protamines) s) in any 10-minute period (see WARNINGS).

Protamine sulfate (protamine (protamines) s) is intended for injection without further dilution; however,if further dilution is desired, 5% Dextrose Injection,or 0.9% Sodium Chloride Injection may be used. Diluted solutions should not be stored since they contain no preservative.

Protamine sulfate (protamine (protamines) s) should not be mixed with other drugs without knowledge of their compatibility, because protamine sulfate (protamine (protamines) s) 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 (protamines) sulfate required also decreases rapidly with the time elapsed following intravenous injection of heparin.For example, if the protamine sulfate (protamine (protamines) s) is administered 30 minutes after the heparin, one-half the usual dose may be sufficient.

The dosage of protamine sulfate (protamine (protamines) s) should be guided by blood coagulation studies (see WARNINGS).Parenteral drug products should be visually inspected for particulate matter and discolouration prior to administration, whenever solution and container permit.


Product Number

C22905 Protamine Sulfate (protamine (protamines) s) Injection, USP 10 mg/mL, 5 mL flip-top vials in packages of 25.

C22930 Protamine Sulfate (protamine (protamines) s) Injection, USP 10 mg/mL, 25 mL fill in a 30 mL flip-top vial, individually packaged.

Store at controlled room temperature, between 15 and 30°C. Do not freeze.

Note: The 25 mL vials are designed for antiheparin treatment in certain cases in which large doses of heparin have been given during surgery and are to be neutralized by large doses of protamine sulfate (protamine (protamines) s) after surgical procedures.

PHARMACEUTICAL PARTNERS OF CANADA, A Division of Abraxis BioScience, Inc. Richmond Hill,ON L4B 3P6. 1-877-821-7724. FDA Rev date: 12/5/2002

Side Effects & Drug Interactions


Intravenous injections of protamine (protamines) may cause a sudden fall in blood pressure, bradycardia, pulmonary hypertension, dyspnea, or transitory flushing and a feeling of warmth. There have been reports of anaphylaxis that resulted in respiratory embarrassment (see PRECAUTIONS).Other reported adverse reactions include systemic hypertension, nausea, vomiting and lassitude. Back pain has been reported rarely in conscious patients undergoing such procedures as cardiac catheterization. Because fatal reactions often resembling anaphylaxis have been reported after administration of protamine sulfate (protamine (protamines) s) , the drug should be given only when resuscitation techniques and treatment of anaphylactoid shock are readily available.


Protamine sulfate (protamine (protamines) s) has been shown to be incompatible with certain antibiotics, including several of the cephalosporins and penicillins (see DOSAGE AND ADMINISTRATION).



Hyperheparinemia or bleeding has been reported in experimental animals and in some patients 30 minutes to 18 hours after cardiac surgery (under cardiopulmonary bypass) in spite of complete neutralization of heparin by adequate doses of protamine sulfate (protamine (protamines) s) at the end of the operation.

Therefore, it is important to keep the patient under close observation after cardiac surgery. Additional doses of protamine sulfate (protamine (protamines) s) should be administered if indicated by coagulation studies, such as the heparin titration test with protamine (protamines) and the determination of plasma thrombin time.

Too-rapid administration of protamine sulfate (protamine (protamines) s) can cause severe hypotensive and anaphylactoid-like reactions (see DOSAGE AND ADMINISTRATION). Facilities to treat shock should be available.




Because of the anticoagulant effect of protamine (protamines) , it is unwise to give more than 100 mg over a short period unless there is certain knowledge of a larger requirement.

Previous exposure to protamine (protamines) through use of protamine (protamines) -containing insulins or during heparin neutralization may predispose susceptible individuals to the development of untoward reactions from the subsequent use of this drug. Reports of the presence of antiprotamine (protamines) antibodies in the serums of infertile or vasectomized men suggest that some of these individuals may react to the use of protamine (protamines) sulfate. Patients with a history of allergy to fish may develop hypersensitivity reactions to protamine (protamines) , although to date no relationship has been established between allergic reactions to protamine (protamines) and fish allergy.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Studies have not been performed to determine potential for carcinogenicity,mutagenicity or impairment of fertility.

Usage in Pregnancy

Animal reproduction studies have not been conducted with protamine sulfate (protamine (protamines) s) . It is also not known whether protamine sulfate (protamine (protamines) s) can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Protamine sulfate (protamine (protamines) s) should be given to a pregnant woman only if clearly needed.

Nursing Mothers

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when protamine sulfate (protamine (protamines) s) is administered to a nursing woman.

Usage in Children

Safety and effectiveness in children have not been established.

Overdose & Contraindications


Because of the anticoagulant effect of protamine sulfate (protamine (protamines) s) , overdosage of this drug may theoretically result in hemorrhage.However, in one study, overdosage of 600 to 800 mg of intravenous protamine sulfate (protamine (protamines) s) had only minimal, transient effects on blood coagulation tests.The patient should be followed with coagulation studies and treated symptomatically.

The LD50 of protamine sulfate (protamine (protamines) s) is 100 mg/kg in mice.


Protamine sulfate (protamine (protamines) s) is contraindicated in patients who have shown previous intolerance to the drug.

Clinical Pharmacology


When administered alone, protamine (protamines) has an anticoagulant effect. However, when it is given in the presence of heparin (which is strongly acidic), a stable salt is formed which results in the loss of anticoagulant activity of both drugs.

Protamine sulfate (protamine (protamines) s) has a rapid onset of action.

Neutralization of heparin occurs within five minutes after intravenous administration. Although the metabolic fate of the heparin-protamine (protamines) complex has not been elucidated, it has been postulated that protamine sulfate (protamine (protamines) s) in the heparin-protamine (protamines) complex may be partially metabolized or may be attacked by fibrinolysin, thus freeing heparin.

Medication Guide


No information provided. Please refer to the WARNINGS and PRECAUTIONS sections.

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