Aminocaproic acid for hemophilia

Last updated Feb. 12, 2024, by Marisa Wexler, MS
Fact-checked by Inês Martins, PhD

What is aminocaproic acid for hemophilia?

Aminocaproic acid, also known as 6-aminocaproic acid or epsilon-aminocaproic acid, is an antifibrinolytic medication that can help to stabilize blood clots.

The medication is not formally approved as a treatment for hemophilia, but it may be used off-label in some situations to help control bleeding in hemophilia patients. It specifically has been used to manage bleeding in the mouth, such as during tooth extractions.

Brand names and formulations

Aminocaproic acid is available as oral tablets or an oral solution under the brand name Amicar. Numerous generic versions of oral Amicar also are available.

An injectable formulation of Amicar previously was available, but it has been discontinued in the U.S.

Therapy snapshot

How does aminocaproic acid work in hemophilia?

Aminocaproic acid is an antifibrinolytic — a medication that works to prevent the breakdown of clots, a process known as fibrinolysis.

Under normal circumstances, fibrinolysis is critical for preventing abnormal or dangerous clots. In people with hemophilia who have impaired clotting, reducing fibrinolysis may help to stabilize clots, so they can control bleeding for longer periods.

Aminocaproic acid specifically works by binding to a protein called plasminogen. This protein normally sits in blood, saliva, and other bodily fluids in its inactive form, but during fibrinolysis, plasminogen is converted into another protein, called plasmin, which is able to destroy blood clots. By blocking the conversion of plasminogen into plasmin, aminocaproic acid can reduce the breakdown of clots.

How is aminocaproic acid administered in hemophilia?

Aminocaproic acid is available in tablets at dosages of 500 or 1,000 mg (1 gram) per tablet. It also is available in a raspberry-flavored oral solution containing 250 mg of the drug per milliliter of liquid.

In people with hemophilia, aminocaproic acid is most commonly used to help manage bleeding in the mouth, especially during tooth extractions or other dental procedures. It also may be used to help with bleeding in other areas that contain mucus membranes, such as the nose, intestines, or genitals.

Aminocaproic acid may be used to manage bleeding in both hemophilia A and B, as well as in another clotting disorder called von Willebrand disease.

The National Bleeding Disorders Foundation recommends that a dosage of replacement therapy containing the missing clotting factor should be administered first to promote clotting, then aminocaproic acid may be given to help the clots stay in place.

As aminocaproic acid is not formally approved for use in hemophilia, there is not a standardized dosing regimen for its use in people with this disease. The dosage typically is determined based on the specific situation of the person being treated and the reasons for treatment. Dosing should not exceed 30 mg per day.

Aminocaproic acid should never be administered to anyone who shows signs of a problematic blood clot within the body’s blood vessels.

Aminocaproic acid in hemophilia clinical trials

A clinical trial conducted in the late 1960s enrolled 31 males with hemophilia A or B who were undergoing tooth extractions. The participants first received standard replacement therapy to raise the activity of the missing clotting factor to 50% of normal before the tooth extraction.

They then were given either an intravenous, or into-the-vein, infusion of either a placebo or aminocaproic acid, at a dose of 6 grams, up to two hours prior to the procedure. Additional 6 mg doses were administered four times per day for seven or 10 days, starting six hours after the tooth extraction.

The results showed that 14 of 16 patients (87.5%) given a placebo experienced at least some bleeding in the mouth following the dental procedure. By comparison, three of 15 patients (20%) given aminocaproic acid did not have any reported bleeding in the mouth following the operation, and those few who did generally reported much less bleeding compared with patients given a placebo.

More than half of patients given a placebo required additional treatment for mouth bleeding after the procedure, compared with one patient given aminocaproic acid — and notably, this individual had chosen to discontinue aminocaproic acid treatment early.

Common side effects of aminocaproic acid

The most common side effects of aminocaproic acid include:

• general discomfort, or malaise
• muscle pain
• kidney impairment
• seizures
• low blood pressure
• slowed heart rate
• abnormal clotting, known as thrombosis
• swelling
• injection site reactions
• nausea and diarrhea.

Kidney risk

When aminocaproic acid is used to manage bleeding in the upper urinary tract, it can cause clots that interfere with the function of the kidneys. Therefore, the medication should only be used to control bleeds in the urinary tract if the potential benefits outweigh these risks.

Muscle damage

In rare cases, long-term use of aminocaproic acid can cause weakness and tissue death, called necrosis, of muscle fibers. This can lead to mild symptoms such as weakness and fatigue, but in some cases, such symptoms may be very severe, potentially leading to rapid muscle breakdown and kidney failure.

Muscle damage related to aminocaproic acid is marked by increased levels of the muscle biomarker creatine phosphokinase, called CPK. Patients taking aminocaproic acid over a long time should have their CPK levels checked regularly, and the therapy should be stopped if levels rise. Muscle damage usually stops after discontinuing the treatment, but restarting aminocaproic acid also may restart muscle damage.

Dry ejaculation

Some men with hemophilia have reported experiencing dry ejaculation (that is, a male orgasm without the accompanying emission of semen) while taking aminocaproic acid. In all reported cases, this issue resolved within a day or two of stopping the treatment.

Use in pregnancy and breastfeeding

Aminocaproic acid has not been investigated in people who are pregnant or breastfeeding. In these situations, the medication should be used with caution and given only if there’s a clear need.

Hemophilia News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.