Aminocaproic Acid Injection: What It Treats, Dosing, Side Effects
Last updated September 7, 2026.
**Aminocaproic acid injection is an antifibrinolytic medicine, given into a vein to control bleeding that happens when the body dissolves clots faster than it can form them.** It blocks the activation of plasminogen into plasmin, the enzyme that breaks down fibrin, so clots that have already formed stay in place long enough for bleeding to stop. It does not make new clots and it does not replace clotting factors, platelets, or blood products. The most important safety point is that it is only for bleeding caused by fibrinolysis: if you have active clotting inside your blood vessels, such as disseminated intravascular coagulation, this drug is not given unless heparin is given with it.
What does it treat?
Aminocaproic acid injection is used for bleeding from enhanced systemic fibrinolysis or from urinary fibrinolysis. In practice that includes bleeding after heart surgery involving cardiopulmonary bypass, bleeding related to liver cirrhosis or a portacaval shunt, bleeding in aplastic anemia, bleeding with abruptio placentae, and bleeding linked to cancers of the prostate, lung, stomach, or cervix. It is also used for urinary tract bleeding after prostate or kidney surgery, and as an add-on for people with hemophilia having dental extractions, alongside factor replacement. The pattern clinicians look for is oozing that keeps returning from surgical sites, gums, or IV sites, with lab evidence of rapid clot breakdown. There are no combination products; aminocaproic acid also comes as oral tablets and an oral solution, and tranexamic acid is a related antifibrinolytic used for similar problems.
How do you take it?
This medicine comes as a 250 mg/mL vial and is always diluted before it goes in. Rapid IV push is not used because it can drop your blood pressure and slow your heart rate. The usual adult approach on the label is 4 to 5 g in 250 mL of diluent infused over the first hour, then a continuous infusion of about 1 g per hour in 50 mL of diluent, kept up for roughly 8 hours or until bleeding is controlled. Do not exceed 30 g in 24 hours. Food and drink rules do not apply, since it goes into a vein rather than your stomach. There is no missed-dose step for you to manage: your nurse runs the infusion and restarts or adjusts it. Doses are lowered if your kidneys are not clearing well or you are making little urine. Tell your team right away if bleeding gets worse instead of better, or if you get muscle pain, dark urine, chest pain, or leg swelling during treatment, since those can mean the infusion should stop.
Side effects to know
- Common: Common effects are nausea, vomiting, diarrhea or stomach cramps, headache, dizziness, feeling washed out, stuffy nose, ringing in the ears, watery or red eyes, and irritation at the IV site.
- Serious: Stop the infusion and get help for muscle pain, weakness, or dark cola-colored urine, which can signal muscle breakdown and kidney injury, and for signs of a clot such as chest pain, trouble breathing, one-sided leg swelling or pain, or new weakness, slurred speech, or facial droop. Also get help right away for hives, swelling of the lips, face, or throat, wheezing, seizures, or a sudden drop in blood pressure with fainting.
Who should not take it?
Aminocaproic acid injection is not used when there is evidence of active clotting inside your blood vessels, and it is not used for bleeding coming from the upper urinary tract, such as the kidney or renal pelvis, because a clot can block urine flow. Tell your clinician if you have kidney disease, heart disease, liver disease, a past blood clot or stroke, or a clotting disorder, and if you are on hormone estrogen products or birth control pills, which raise clot risk when combined with this drug. Using it with factor IX complex concentrates or anti-inhibitor coagulant complexes also raises clot risk. Some vials contain benzyl alcohol, which is avoided in newborns. In pregnancy, current FDA labeling states there are no adequate and well-controlled studies, so it is used only if clearly needed; it is not known whether the drug passes into breast milk, so tell your team if you are nursing. There is no specific alcohol interaction on the label, but drinking during an active bleeding episode is not advised and alcohol adds to dizziness and nausea, so ask your team before you drink after discharge.
When is it an emergency?
Call 911 in the US for chest pain, trouble breathing, coughing up blood, fainting or collapse, seizures, sudden weakness or numbness on one side, slurred speech, or swelling of the face, lips, or throat with hives or wheezing. Call 911 too for bleeding you cannot control with firm pressure, or for a sudden severe headache. If too much is given or someone swallows the oral form by mistake, call Poison Control at 1-800-222-1222 right away, even if the person seems fine; overdose has been linked to very low blood pressure, kidney failure, and clotting. Passing little or no urine, or dark brown urine with muscle pain and weakness, needs same-day medical assessment rather than waiting for the next appointment.
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Common questions
What is the maximum dose of aminocaproic acid injection in a day?
Do not exceed 30 g in 24 hours. A typical adult regimen is 4 to 5 g diluted in 250 mL infused over the first hour, then about 1 g per hour in 50 mL as a continuous infusion. That is usually continued for around 8 hours, or until the bleeding is controlled. Your dose may be lowered if your kidneys are not clearing normally or you are producing little urine, because the drug leaves your body mostly through the kidneys. The infusion is run by your care team, so you do not calculate any of this yourself.
Can I drink alcohol while I am on aminocaproic acid?
The FDA label does not list a specific interaction between alcohol and aminocaproic acid. The practical answer is still no while you are being treated: you are getting this drug for active bleeding, and alcohol thins out your judgment, worsens the dizziness and nausea the drug can cause, and can irritate the stomach lining if your bleeding is from the gut. Liver disease is a common reason people need this drug, and alcohol makes liver-related bleeding worse. Ask your clinician when it is reasonable to drink again after your bleeding episode has resolved.
Is aminocaproic acid injection safe in pregnancy or while breastfeeding?
Current FDA labeling states there are no adequate and well-controlled studies in pregnant women, so it is used during pregnancy only if the benefit clearly justifies it. Obstetric bleeding, including abruptio placentae, is one of the situations where it may be used. It is not known whether aminocaproic acid passes into breast milk, so tell your team if you are nursing and they will advise on timing feeds or pumping. Some vials also contain benzyl alcohol as a preservative, which is avoided in newborns. Always tell the team giving the infusion if you are pregnant, might be pregnant, or are breastfeeding.
Do I need to take it with food, and can I eat during the infusion?
Food rules do not apply to the injection, because it goes straight into a vein and never passes through your stomach. You can usually eat and drink normally during the infusion unless you are being kept fasting for surgery, a procedure, or active gastrointestinal bleeding. If the drug makes you nauseated, small bland meals and slower sipping help. The oral tablets and oral solution of aminocaproic acid can be taken with or without food.
What are the signs of getting too much aminocaproic acid?
Reported overdose effects include a sharp drop in blood pressure, acute kidney failure, and clotting in the blood vessels. Warning signs to act on are fainting or near-fainting, passing very little or no urine, dark brown urine with muscle pain and weakness, chest pain, trouble breathing, or one-sided leg swelling. If you think too much was given or someone swallowed the oral form by mistake, call Poison Control at 1-800-222-1222 in the US right away. Call 911 for collapse, seizures, or trouble breathing.
What medicines and conditions interact with aminocaproic acid?
Using it with factor IX complex concentrates or anti-inhibitor coagulant complexes raises the risk of clots, so those combinations need careful review. Estrogen-containing products, including many birth control pills and hormone therapy, also add clot risk. It is not given when there is evidence of active clotting inside the blood vessels unless heparin is given alongside it, and it is not used for bleeding coming from the kidney or renal pelvis, because a clot can block urine flow. Tell your clinician about kidney disease, heart disease, liver disease, and any past clot or stroke. Bring a full list of your medicines and supplements to the team running the infusion.