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protamine

Generic
Used for Anticoagulant Reversal
Used for Anticoagulant Reversal

Protamine is an anticoagulant reversal agent that helps to stop bleeding caused by heparin. Protamine is typically given in a hospital setting as an intravenous (IV) injection over 10 minutes. And it begins to work within 5 minutes. Side effects include low blood pressure and slow heart rate, so your provider will keep an eye on these to make sure they don't drop too low.

Reviewed by:
reviewer
Robert Chad Hakim, PharmD, BCCCP
reviewer
Allison Gourley, PharmD
Last reviewed on October 30, 2023
BasicsSide effectsPros & consPharmacist tipsFAQsWarningsDosageLatest newsReferencesPricesMedicare
basics-icon

What is Protamine?

What is Protamine used for?

  • To treat bleeding caused by heparin

How Protamine works

Protamine is an anticoagulant reversal agent. It works by attaching to heparin and preventing it from making your blood thinner. This way, it stops any bleeding that might be happening.

Drug Facts

Common BrandsNo brands available
Drug ClassAnticoagulant reversal agent
Controlled Substance ClassificationNot a controlled medication
Generic StatusLower-cost generic available
AvailabilityPrescription only
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What are the side effects of Protamine?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Low blood pressure
  • Slow heart rate

Other Side Effects

  • Back pain
  • Shortness of breath
  • Nausea
  • Vomiting
  • Flushing
  • Lacking energy

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Serious allergic reaction: difficulty breathing, tightness in the throat, hives, fast heartbeat, dizziness, lightheadedness, swelling in the face or tongue

Source: DailyMed

pros-and-cons

Pros and cons of Protamine

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Pros

Works quickly to reverse the effects of heparin

Given as an IV injection over 10 minutes

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Cons

Needs to be given in a healthcare setting

Can suddenly lower blood pressure and heart rate

pharmacist-tips

Pharmacist tips for Protamine

pharmacist

  • Your provider will order blood tests (e.g., complete blood count) and examine you for signs and symptoms of bleeding after receiving protamine to see how well you respond to the medication.

    • Make sure to let your provider know if you are taking a blood thinner at home. They'll decide if and when you should restart it after receiving protamine.

      faqs

      Frequently asked questions about Protamine

      How long does it take for protamine to work?
      Protamine starts to work within 5 minutes and can last for up to 2 hours.
      What is the difference between protamine and vitamin K?
      Protamine and vitamin K (phytonadione) are two completely different medications. They're both used to stop bleeding of blood thinners, but protamine is used to treat a heparin overdose while vitamin K (phytonadione) is used to treat a warfarin (Coumadin) overdose.
      Who should not get protamine?
      People who've had a past reaction to protamine are more likely to develop another allergic reaction to the medication. Also, those who have a fish allergy could also be at higher risk for an allergic reaction to protamine because it comes from salmon sperm.
      Does protamine lower blood pressure?
      Yes, a sudden drop in blood pressure and heart rate are possible side effects of protamine. This is thought to happen because protamine releases a chemical that causes your blood vessels to widen. Your provider will likely monitor your blood pressure and heart rate before and after receiving protamine to make sure it doesn't get too low.
      Does protamine stop bleeding from enoxaparin (Lovenox)?
      It can. While protamine isn't FDA approved to stop bleeding caused by an excess of enoxaparin (Lovenox), too much enoxaparin (Lovenox), some providers use it off-label because it works to some degree. The dose depends on when enoxaparin (Lovenox) was given, but in general, it's 0.5 to 1 mg of protamine per 1 mg of enoxaparin (Lovenox).
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      What are the risks and warnings for Protamine?

      Protamine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

      risk-warning

      Severe heart problems

      • Risk factors: Rapid administration of protamine | High dose of protamine | Repeated doses of protamine | Using other medications that also contain protamine

        Although rare, protamine can cause severe heart problems, including low blood pressure, slow heart rate, sudden collapse, and fluid overload in the lungs. Your provider will monitor your vitals closely before, during, and after you receive protamine and provide treatment if needed.

        risk-warning

        Serious allergic reactions

        Serious allergic reactions to protamine are possible, including life-threatening reactions like anaphylaxis (e.g., closing of the throat). Your provider will monitor you for symptoms like dizziness, nausea, a choking sensation, difficulty breathing, swelling around your eyes, or swelling of the lips or tongue while you're receiving protamine.

        dosage

        Protamine dosage forms

        Typical dosing for Protamine

        Your provider will help determine your dose. The typical dose depends on the amount of heparin you receive. Each 1 mg of protamine is given for about every 100 units of heparin. The maximum dose is 50 mg.

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        References

        Best studies we found

        Applefield, D., et al. (2023). Protamine. StatPearls.

        Dhakal, P., et al. (2016). Reversal of anticoagulation and management of bleeding in patients on anticoagulants. Clinical and Applied Thrombosis/Hemostasis.

        Frenesius Kabi USA, LLC. (2023). Protamine sulfate injection, solution [package insert]. DailyMed.

        View All References (2)

        Hafner, C., et al. (2012). 390 Protamine allergy. The World Allergy Organization Journal.

        Pearson, P. J. (1992). Protamine releases endothelium-derived relaxing factor from systemic arteries. A possible mechanism of hypotension during heparin neutralization. Circulation.

        GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.
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