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Heparin Reversal Agent

Protamine Sulphate

Brand names: Prosulf

Protamine sulphate is a heparin antagonist used to reverse the anticoagulant effect of unfractionated heparin, most commonly after cardiopulmonary bypass.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

Being strongly basic, it binds the acidic heparin molecule to form a stable inactive complex, neutralising heparin's anticoagulant activity.

Prescribing in practice

  • It can cause severe hypotension, bradycardia and anaphylactoid reactions, especially with rapid administration, so it must be given slowly with resuscitation facilities available.
  • Given in excess or without circulating heparin it has an intrinsic anticoagulant effect, and it only partially reverses low-molecular-weight heparins.
  • Risk of serious reactions is increased in patients previously exposed to protamine-containing insulins, those with fish allergy and men who have had a vasectomy.

Monitoring

Monitor blood pressure, heart rate and clotting status, using anticoagulation assays such as activated clotting time to guide and confirm reversal.

Counselling the patient

  • Given slowly by trained staff with close cardiovascular monitoring.
  • Flag any history of fish allergy, previous protamine reactions or protamine-containing insulin use before administration.

Evidence & guidelines

Its use for heparin reversal after cardiac surgery is standard practice supported by the SPC and cardiothoracic anaesthesia guidance.

Reference: AAGBI Guidelines; Society of Thoracic Surgeons Guidelines on Anticoagulation; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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