Protamine sulfate

By Medically reviewed by hellodoktor

Generic Name: Protamine sulfate Brand Name(s): Generics only. No brands available.


What is protamine sulfate used for?

Protamine sulfate is commonly used for the treatment of severe heparin overdose resulting in hemorrhage.

It is indicated to neutralize heparin that is administered during extracorporeal circulation in arterial and cardiac surgery or dialysis procedures. Also, it may be used to neutralize the hemorrhagic effects following overdose of the low molecular weight heparin, enoxaparin.

How should I take protamine sulfate?

This drug is administered by very slow IV injection over 10 minutes. May be administered without further dilution at a concentration of 10 mg/mL.

However, if more dilute infusion solution is desired, further dilution in 5% dextrose or 0.9% sodium chloride injection recommended. Contains no preservatives; discard unused portion.

How do I store protamine sulfate?

Protamine sulfate is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store protamine sulfate in the bathroom or the freezer. There may be different brands of protamine sulfate that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush protamine sulfate down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using protamine sulfate?

Before using this drug, tell your doctor if:

  • You are pregnant or breastfeeding. This is because, while you are expecting or feeding a baby, you should only take medicines on the recommendation of a doctor.
  • You are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • You have allergy with any of active or inactive ingredients of protamine sulfate or other medications.
  • You have any other illnesses, disorders, or medical conditions.

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, repeated doses, previous administration of protamine, and current or previous use of protamine-containing drugs (NPH insulin, protamine sulfate zinc insulin, and certain beta-blockers).

Allergy to fish, previous vasectomy, 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.

Heparin rebound causing bleeding may occur 8-9 hours after protamine sulfate administration.

May be ineffective in cardiac surgery patients despite adequate dose.

Rapid infusion reactions can cause severe hypotensive reactions.

Is it safe during pregnancy or breastfeeding?

There are no adequate studies in women for determining risk when using protamine sulfate during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking protamine sulfate. Protamine sulfate is pregnancy risk category C, according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk
  • B=No risk in some studies
  • C=There may be some risk
  • D=Positive evidence of risk
  • X=Contraindicated
  • N=Unknown

It is not known whether protamine sulfate is distributed into breast milk. However, problems in humans have not been documented.

Side effects

What side effects can occur from protamine sulfate?

When using this drug, tell your doctor if:

  • Anaphylaxis
  • Hypotension
  • Decreased O2 consumption
  • Flushing
  • Pulmonary hypertension
  • Uncontrollable bleeding
  • Circulatory collapse
  • Pulmonary edema

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with protamine sulfate?

Protamine sulfate may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with protamine sulfate?

Protamine sulfate may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with protamine sulfate?

Protamine sulfate may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using protamine sulfate.

What is the dose of protamine sulfate for an adult?

Heparin Neutralization

The recommended dose is 1-1.5 mg per 100 USP units of heparin; not to exceed 50 mg.

Monitor APTT 5-15 min after dose then in 2-8 hr.

In accidental overdoses of heparin, consider t1/2 heparin 60-90 min.

In setting without bleeding complications, consider observation, rather than reversal of anticoagulation with protamine sulfate (avoids ADR’s).

Complex of protamine sulfate and heparin may degrade over time requiring further doses.

Dalteparin or Tinzaparin Overdose

The recommended dose is 1 mg protamine sulfate for 100 units dalteparin or tinzaparin; if PTT prolonged 4hr after protamine sulfate overdose administer 0.5 mg per 100 units of dalteparin or tinzaparin.

Enoxaparin Overdose

The recommended dose is 1 mg per mg enoxaparin (if enoxaparin overdose given within 8 hr); if >8 hour of overdose or bleeding continues after 4 hours after first dose, give 0.5 mg protamine sulfate per mg enoxaparin.

Time Elapsed Since Heparin Dose

Dose of protamine sulfate (mg) to neutralize 100 units of heparin

  • <1/2 hr: The recommended dose is 1-1.5 mg/100 units of heparin.
  • 30-120 min: The recommended dose is 0.5-0.75 mg/100 units of heparin.
  • >2 hr: The recommended dose is 0.25-0.375 mg/100 units of heparin.

What is the dose of protamine sulfate for a child?

The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is protamine sulfate available?

Protamine sulfate is available in the following dosage forms and strengths:

  • IV solution 10 mg/mL

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of protamine sulfate, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: April 19, 2017 | Last Modified: September 13, 2019

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