A clotting regulator replaced in severe protein C deficiency
Protein C
A blood-derived medicine used to replace protein C in severe inherited protein C deficiency, helping prevent dangerous blood clotting.
What is Protein C?
Protein C is a natural substance in the blood that helps keep clotting under control. Some people are born with a severe lack of it, which can lead to dangerous clotting, including a serious skin and clotting condition called purpura fulminans. This medicine is a concentrate of protein C, given into a vein to replace what is missing and prevent or treat these clots. Because it is made from human blood plasma, it carries the usual small precautions of a blood product, and as it affects clotting it can be linked with bleeding if anticoagulation goes too far. Allergic reactions are also possible.
Education and reference only. This is a plain-language guide to Protein C — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Protein C is a protein the body normally makes to help regulate blood clotting, acting as a natural brake so clots do not form when they should not. People with severe inherited protein C deficiency lack this brake, and can suffer dangerous clots, including purpura fulminans, a severe condition affecting the skin and small blood vessels, often appearing soon after birth. This medicine is a concentrate of protein C, prepared from human blood plasma, given into a vein to replace the missing protein. It is a specialist treatment used and supervised by haematology teams.
How it works
Protein C, once activated in the body, dampens down the clotting process, helping to prevent clots from forming inappropriately. In severe protein C deficiency this natural control is missing, so clots can form dangerously, damaging the skin and blocking small blood vessels. Giving the protein C concentrate replaces what is missing, restoring this clot-limiting control and helping to prevent or treat episodes such as purpura fulminans. Because it works directly on the clotting balance, the dose is guided by the situation and by tests, and it is sometimes used alongside other anticoagulation under specialist care.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist blood-derived medicine used in the UK to replace protein C in people with severe inherited protein C deficiency, to prevent dangerous clotting.
Practical use
How to take Protein C
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given as an injection or drip into a vein, by or under the supervision of a specialist haematology team.
- The dose and timing are set by the team based on your condition and blood tests.
- It may be used alongside other anticoagulation, so follow the team's plan carefully.
- Tell the team straight away about any signs of an allergic reaction during or after treatment.
- Report any unusual bruising or bleeding, as the dose may need reviewing.
Weighing it up
Advantages & disadvantages of Protein C
Advantages
- Replaces the missing protein C in severe deficiency, helping prevent dangerous clots.
- Can treat and help prevent serious conditions such as purpura fulminans.
- Allows clotting control to be restored in a condition that is otherwise very hard to manage.
Disadvantages
- Made from human blood plasma, so it carries the usual precautions of a blood product.
- Can be associated with bleeding if anticoagulation is pushed too far.
- Allergic or hypersensitivity reactions are possible, and it needs specialist supervision.
Practical use
Good to know
The key thing to understand is that protein C concentrate replaces a missing natural brake on clotting, used in severe inherited protein C deficiency to prevent or treat dangerous clots such as purpura fulminans. Because it is prepared from human blood plasma, it carries the standard, very carefully managed precautions of a plasma-derived product, and allergic or hypersensitivity reactions are possible, so it is given with the team ready to respond. It works on the clotting balance, so if anticoagulation is pushed too far there is a risk of bleeding, which is why treatment is guided by tests and specialist judgement. It is given into a vein by, or under the close supervision of, a haematology team, who decide the dose and timing based on the individual.
Who should not take it / use with caution
- People who have had a serious allergic reaction to protein C concentrate or its components should not use it.
- It is used with care in anyone at high risk of bleeding, with the dose guided by tests.
- It is used only under specialist haematology supervision.
Monitoring
- Blood tests to guide the dose and check the clotting balance.
- Watching for signs of bleeding or bruising.
- Watching for allergic or infusion-related reactions during treatment.
Side effects
- Allergic or hypersensitivity reactions, such as rash, itching or, rarely, more serious reactions.
- Bleeding or bruising if the clotting balance is shifted too far.
- Reactions related to the infusion, such as feeling unwell during the drip.
Key interactions
- It affects the clotting balance, so it is used carefully with other anticoagulant medicines.
- The team takes account of any medicines that increase bleeding risk.
- Tell the team about all your medicines so clotting treatment can be balanced safely.
Available as: A powder made up into a solution and given as an injection or drip into a vein.
Answers
Protein C: frequently asked questions
What is protein C used for?
It replaces protein C, a natural brake on clotting, in people with severe inherited protein C deficiency, to prevent or treat dangerous clots such as purpura fulminans.
Why does it matter that it comes from blood plasma?
It is prepared from human blood plasma, so it carries the standard, carefully managed precautions of a plasma-derived product, which your specialist team will explain.
Can it cause bleeding?
Because it works on the clotting balance, pushing anticoagulation too far can lead to bleeding, which is why treatment is guided by blood tests and specialist judgement.
Are allergic reactions possible?
Yes, allergic or hypersensitivity reactions can occur, so it is given by a team ready to respond, and any rash, itching or feeling unwell should be reported straight away.
Who gives this treatment?
It is given into a vein by, or under the close supervision of, a specialist haematology team, who set the dose and timing for each person.
Authoritative sources
- BNF
- NICE CKS
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