Antifibrinolytic
Tranexamic acid
Also called TXA
Indications
- Trauma hemorrhage within 3 h of injury (off-label; CRASH-2)
- Postpartum hemorrhage within 3 h of birth (off-label; WOMAN, WHO)
- Cardiac, orthopedic and spine surgery to cut blood loss and transfusion (off-label)
- Mild to moderate TBI within 3 h (off-label; CRASH-3)
- Fibrinolytic bleeding: high LY30 on TEG or ROTEM, or bleeding after thrombolysis (off-label)
- Hemophilia patients having tooth extraction, short term (label)
Dosing
| Where | Dose |
|---|---|
| Other common pushes | Tranexamic acid: 1 g IV over 10 min within 3 h of trauma, then 1 g over 8 h |
On the quick cards
- Tranexamic acid (Cyklokapron)EMS Field Drugs: Trauma: antifibrinolytic for hemorrhagic shock
- Other common pushesPush and Emergency Meds: Analgesia, antiemetics, steroids, diuretics, TXA
Mechanism of action
Tranexamic acid is a synthetic analog of the amino acid lysine. It occupies the lysine-binding sites on the kringle domains of plasminogen, so plasminogen cannot bind the lysine residues of fibrin where tPA activates it, and the plasmin that does form binds fibrin poorly; the clot is spared. At much higher concentrations it also inhibits plasmin directly. It is about 10 times more potent than aminocaproic acid in vitro (label).
Pharmacology
- Hematologic: stabilizes clot (lowers LY30) without raising factor levels or platelets
- Hematologic: CRASH-2 death 14.5% vs 16.0%; benefit was greatest within 1 h, and starting after 3 h raised bleeding deaths
- Hematologic: postpartum bleeding deaths 1.5% vs 1.9%, and 1.2% vs 1.7% when given within 3 h (WOMAN)
- GI: no benefit in GI bleeding and more venous clots (0.8% vs 0.4%; HALT-IT)
- CNS: at high levels it blocks inhibitory glycine and GABA-A receptors, causing seizures (Lecker 2012)
- Cardiovascular: hypotension with rapid IV injection; give no faster than 100 mg/min (label)
Pharmacokinetics
| Onset | Minutes after IV dosing |
|---|---|
| Duration | Antifibrinolytic levels last about 7–8 h in serum and 17 h in tissues (label) |
| Half-life | Terminal about 2 h (US label) to 3 h (UK SmPC) |
| Distribution | Initial Vd 9–12 L (label); CSF about one tenth of plasma; crosses the placenta |
| Protein binding | About 3%, all to plasminogen |
| Metabolism | Negligible |
| Elimination | Glomerular filtration: over 95% unchanged in urine, about 90% within 24 h (label) |
| Organ failure | Accumulates in kidney failure; dose cut by serum creatinine (label) |
| Routes | IV or oral; topical or nebulized (off-label); never neuraxial |
Chemistry
- trans-4-(aminomethyl)cyclohexanecarboxylic acid, C₈H₁₅NO₂, MW 157.2: a synthetic, ring-constrained lysine analog; the trans isomer is the active one
- pKa about 4.3 (carboxyl) and 10.2–10.6 (amine): a zwitterion at pH 7.4, very water-soluble and barely lipid-soluble, so it enters the CNS slowly and leaves by the kidney
- Injection 100 mg/mL (1 g/10 mL) in water, pH 6.5–8.0, preservative-free
- Mixes with electrolyte, dextrose, amino acid and dextran solutions and heparin; not with blood or penicillin solutions (label)
Adverse effects and cautions
In the one-pagers
- Trauma: Primary and Secondary SurveyDamage control resuscitation: TXA within 3 hours for hemorrhagic shock (often SBP <90 or HR >110): 1 g IV over 10 min, then 1 g over 8 h; EMS may give 2 g once
- Obstetric EmergenciesPostpartum hemorrhage: Tranexamic acid: 1 g IV over 10 min; repeat once after 30 min if bleeding: Only within 3 h of birth
- Pulmonary EmbolismNursing: monitoring and bleeding watch: Major bleeding: cryoprecipitate to fibrinogen ≥150 mg/dL, tranexamic acid, protamine for UFH
- Abdominal, GI Bleeding, GU and Dialysis EmergenciesGI bleeding: No TXA for GI bleeding. HALT-IT (12,009 patients): bleeding deaths 3.7% vs 3.8%, venous clots 0.8% vs 0.4%. Field TXA is for trauma within 3 h (and PPH).
- Common EMS MedicationsPain, sedation, nausea and bleeding: TXA, antifibrinolytic: Trauma with hemorrhagic shock: 1 g IV over 10 min, or 2 g IV/IO: >3 h since injury
- ECMO EssentialsComplications: prevention, recognition, management: For bleeding, hold or lower heparin (ELSO 2021: 4–6 h is reasonable, 12 h or longer for intracranial or surgical bleeding), replace fibrinogen and platelets, consider tranexamic acid, and get local control; coated circuits run without heparin for days while flow stays high. Intracranial hemorrhage occurs in about 2–8% of adult runs and kills abou
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In the algorithms
- Traumatic Cardiac Arrest
- Field Delivery and Newborn Care
- Massive Hemoptysis
- Massive Pulmonary Embolism
- Massive Hemorrhage
- Postpartum Hemorrhage
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Sources
- FDA label: Cyklokapron (2025)
- CRASH-2 (Lancet 2010)
- WOMAN (Lancet 2017)
- Lecker 2012 (JCI, seizures)
For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow your local protocols and medical direction.