Protamine sulfate

(Redirected from Protamine)


  • Type: Antidote
  • Dosage Forms:
  • Routes of Administration: IV
  • Common Trade Names:

Adult Dosing

  • Major bleeding due to unfractionated heparin:
    • 1 mg IV for every 100 units of heparin infused in past 3h
    • Do not infuse faster than 50mg/10min
    • If it has been >30min since last heparin injection, 0.5mg may be sufficient
    • Give slowly over 1-3min; do not exceed 50mg in any 10 minute period (anaphylaxis risk)
    • Because half-life is short (7 min) may require second treatment
  • Major bleeding due to low-molecular-weight heparin:
    • Protamine is less effective for bleeding from LMWH than it is with heparin-induced bleeds
    • Enoxaparin: 1 mg IV for every 1 mg enoxaparin administered in past 8h
    • Dalteparin: 1 mg IV for every 100 anti-Xa international units of dalteparin

Pediatric Dosing

Safety/Efficacy not well established in pediatrics, but unofficial suggested dosing similar to adult dosing

Special Populations


  • Allergy to class/drug

Adverse Reactions


  • Anaphylaxis(0.2% of patients), anaphylactoid reaction
  • Circulatory collapse, capillary leak, bradyarrhythmia, hypotension
  • Pulmonary edema


  • Flushing
  • Dyspnea
  • Nausea/vomiting


  • Half-life:
    • ~7 minutes
  • Metabolism:
  • Excretion:

Mechanism of Action

  • Weak anticoagulant, heparin antagonist


See Also


  • Protamine sulfate: Drug information. UpToDate. Accessed April 2, 2019.