An antifibrinolytic medicine that reduces excessive bleeding
Aminocaproic acid
An antifibrinolytic medicine that reduces excessive bleeding by stopping clots from breaking down too soon.
What is Aminocaproic acid?
Aminocaproic acid is an antifibrinolytic medicine, meaning it reduces excessive bleeding by stopping blood clots from breaking down too quickly. It works in a similar way to tranexamic acid, and is used in situations where bleeding is heavier than normal because clots dissolve too fast. Because it helps clots last longer, the main concern is an increased risk of unwanted clots, so it is avoided where clotting risk is high. With long-term use it can occasionally cause muscle problems. It is used under medical supervision.
Education and reference only. This is a plain-language guide to Aminocaproic acid — 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
Aminocaproic acid is a medicine that helps control excessive bleeding. It belongs to a group called antifibrinolytics, which work by protecting blood clots so they are not dissolved too soon. It is used in conditions where bleeding is increased because the body breaks down clots too quickly, and its role is similar to the more commonly used tranexamic acid. It can be given by mouth or into a vein, depending on the situation, and is used under medical guidance, often in a hospital or specialist setting.
How it works
When the body forms a clot to stop bleeding, it also has a system that later dissolves clots once they are no longer needed. In some situations this clot-dissolving system is too active, so clots break down too soon and bleeding continues. Aminocaproic acid blocks this clot-dissolving process, allowing clots to hold and bleeding to settle. Because it makes clots more stable, it has to be used carefully in people who are already prone to forming unwanted clots, as it could increase that risk.
Company & origin
Originated / developed by: Specialist manufacturers.
A medicine used to reduce heavy or excessive bleeding by helping blood clots stay stable, with a role similar to tranexamic acid.
Practical use
How to take Aminocaproic acid
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take or receive it exactly as prescribed; it may be given by mouth or into a vein depending on the situation.
- Tell your medical team about any history of blood clots, as this affects whether it is suitable.
- Report any new or unexplained muscle pain or weakness, especially with longer use.
- Stay well hydrated and follow any specific advice given alongside it.
- Do not take it for longer than advised, and attend any reviews or blood tests arranged.
Weighing it up
Advantages & disadvantages of Aminocaproic acid
Advantages
- Reduces heavy or excessive bleeding by keeping clots from breaking down too soon.
- Can be given by mouth or into a vein to suit the situation.
- Works in a similar way to tranexamic acid, an established approach to bleeding.
Disadvantages
- Can increase the risk of unwanted blood clots because it stabilises clots.
- With long-term use it can occasionally cause muscle aches or muscle damage.
- Needs careful use and is generally less commonly used than tranexamic acid.
Practical use
Good to know
The most useful way to think of aminocaproic acid is as a medicine that keeps clots from dissolving too soon, which is why it reduces excessive bleeding. The flip side is the most important safety point: because it stabilises clots, it can raise the risk of clots forming where they are not wanted, so it is avoided or used very cautiously in people who already have a high clotting risk or active clotting inside the body. It works in a similar way to tranexamic acid, which is the more familiar option in the UK. With long-term use it can occasionally cause muscle aches or muscle damage, so any new or unexplained muscle pain or weakness should be reported. It is used under medical supervision, with the dose and route chosen for the situation.
Who should not take it / use with caution
- People who have had a serious allergic reaction to it should not take it.
- It is avoided in people with active unwanted clotting inside the body or a high risk of clots.
- It is used with care in people with kidney problems and under medical guidance generally.
Monitoring
- Watching for signs of unwanted clots, such as leg swelling, chest pain or breathlessness.
- Checking for muscle pain or weakness, especially during longer use.
- Reviewing kidney function and how well bleeding is being controlled.
Side effects
- Nausea, stomach upset or diarrhoea in some people.
- An increased tendency to form unwanted blood clots.
- With long-term use, muscle aches or, rarely, muscle damage, which should be reported.
Key interactions
- It should be used cautiously with medicines that increase clotting risk, such as certain hormone treatments.
- It can interact with clotting-related medicines, so tell your team about all your medicines.
- It is used carefully alongside other treatments given to control bleeding.
Available as: Available as a preparation taken by mouth or given into a vein.
Answers
Aminocaproic acid: frequently asked questions
What is aminocaproic acid used for?
It is an antifibrinolytic medicine used to reduce heavy or excessive bleeding by stopping blood clots from breaking down too quickly.
How is it similar to tranexamic acid?
Both are antifibrinolytics that protect clots so they last longer; tranexamic acid is the more commonly used option in the UK.
Why can it cause clots?
Because it stops clots being dissolved, it can make clots more likely to form where they are not wanted, so it is avoided when clotting risk is high.
Should I worry about muscle pain?
With longer-term use it can occasionally cause muscle aches or muscle damage, so report any new or unexplained muscle pain or weakness.
How is it given?
Depending on the situation it can be taken by mouth or given into a vein, always under medical supervision.
Authoritative sources
- BNF
- NICE CKS
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