What are the absolute contraindications for tranexamic acid?

October 11, 2025 •

3 min read

Tranexamic acid, an antifibrinolytic drug, has shown life-saving efficacy in managing severe bleeding, with the CRASH-2 trial highlighting its benefit in major trauma. However, certain patient profiles present absolute contraindications for tranexamic acid, requiring careful medical assessment before administration to prevent potentially fatal outcomes.

Quick Summary

This guide details the specific conditions and patient histories that make tranexamic acid unsafe for use, including active clotting, subarachnoid hemorrhage, and severe hypersensitivity. It explains why these are non-negotiable restrictions.

Key Points

Active Clotting: Tranexamic acid is absolutely contraindicated in patients with active intravascular clotting due to the high risk of severe thromboembolic events like deep vein thrombosis or pulmonary embolism.
Subarachnoid Hemorrhage: Its use is strictly prohibited in cases of subarachnoid hemorrhage due to the increased risk of cerebral ischemia and infarction, outweighing any potential benefit in controlling bleeding.
Severe Allergy: Patients with a history of severe hypersensitivity or anaphylaxis to TXA should never receive the medication, as re-exposure can trigger a life-threatening reaction.
Color Vision Issues: The drug is contraindicated in patients with an acquired defective color vision due to the risk of visual disturbances and potential retinal changes.
Drug Interactions: Certain combinations, such as TXA with hormonal contraceptives or specific pro-thrombotic agents, significantly increase the risk of dangerous blood clots and are contraindicated.
Neuraxial Route: Tranexamic acid must never be administered via the neuraxial (intrathecal, epidural) route, as this carries a high risk of seizures and cardiac arrhythmias.

The Mechanism and Role of Tranexamic Acid

Tranexamic acid (TXA) is a synthetic derivative of the amino acid lysine. Its primary mechanism of action is as an antifibrinolytic, meaning it prevents the breakdown of blood clots. It works by competitively inhibiting the activation of plasminogen to plasmin. Plasmin is the enzyme responsible for breaking down fibrin, the meshwork that stabilizes a blood clot. By blocking plasmin's activity, TXA helps to stabilize and prolong the life of clots, thereby reducing blood loss. Because of this powerful effect, TXA is used in various clinical settings to manage and prevent excessive bleeding, including heavy menstrual bleeding, hemorrhage after trauma, dental extractions in hemophiliacs, and certain surgeries. While its efficacy is well-established, its use must be carefully weighed against potential risks, particularly in patients with certain absolute contraindications.

Absolute Contraindications for Tranexamic Acid

Absolute contraindications are conditions where the administration of a medication is strictly prohibited because the risk of harm outweighs any potential benefit. For TXA, these are primarily related to its pro-coagulant effect and potential severe reactions.

Active Intravascular Clotting (Thromboembolic Disease)

TXA's clot-stabilizing action can worsen existing clotting conditions like disseminated intravascular coagulation (DIC). This increases the risk of serious thromboembolic events such as DVT, PE, myocardial infarction, or ischemic stroke. Therefore, TXA is contraindicated in active thromboembolic disease.

Subarachnoid Hemorrhage (SAH)

Tranexamic acid is contraindicated in subarachnoid hemorrhage (SAH). Its use in SAH is linked to an increased risk of cerebral edema and infarction, with trials showing no improvement in outcomes and potential harm.

Severe Hypersensitivity or Anaphylaxis

A history of severe allergic reaction or anaphylaxis to TXA or its components is an absolute contraindication. Re-exposure can cause a life-threatening reaction.

Acquired Defective Color Vision

TXA can cause visual disturbances, including changes in color vision. Patients with existing acquired defective color vision should avoid TXA. Ophthalmic monitoring is recommended for long-term TXA use, and the drug should be stopped if visual changes occur.

Concomitant Use of Certain Pro-thrombotic Agents

TXA is contraindicated with certain pro-thrombotic medications like Factor IX complex concentrates and anti-inhibitor coagulant concentrates due to a significantly increased thrombosis risk.

Neuraxial Administration

TXA injection is for intravenous use only. Neuraxial administration is an absolute contraindication linked to severe adverse reactions, including seizures and cardiac arrhythmias.

Relative Contraindications and Necessary Precautions

These conditions require careful assessment but do not always prohibit TXA use.

Renal Impairment: TXA is kidney-excreted; dosage adjustments are needed in renal dysfunction to prevent toxicity. Severe renal impairment is a strong relative contraindication.
History of Seizure Disorder: High TXA doses are linked to increased seizure risk, especially in those with a history. Close monitoring is needed, and discontinuation if seizures occur.
Hormonal Contraceptives: Combined use with hormonal contraceptives may increase thromboembolic risk. Non-hormonal contraception may be advised.
History of Thromboembolism: A past history indicates a clotting predisposition and requires careful risk-benefit evaluation.

Absolute vs. Relative Contraindications: A Comparison


Feature	Absolute Contraindication	Relative Contraindication / Precaution
Definition	A condition that completely prohibits the use of TXA due to unacceptable risk.	A condition that requires careful consideration of the risk-benefit ratio before using TXA.
Primary Goal	To prevent life-threatening or irreversible harm.	To mitigate risk by adjusting dose, monitoring, or seeking alternative treatment.
Examples	Active intravascular clotting, Subarachnoid hemorrhage, Severe hypersensitivity, Defective color vision, Neuraxial administration, Concomitant pro-thrombotic agents.	Renal impairment, History of seizure disorder, Concomitant hormonal contraceptives, History of thromboembolic events.
Decision-Making	A definitive 'no' from the healthcare provider.	A nuanced decision based on patient-specific factors, requiring close supervision.

Conclusion: Weighing the Risks

Tranexamic acid is vital for managing severe bleeding, but its use carries risks in certain patients. Adhering to absolute contraindications is crucial for safety, as conditions like active clotting, SAH, and severe hypersensitivity can lead to catastrophic outcomes. Careful consideration of relative contraindications is also essential for safe use. Awareness of these parameters helps balance TXA's benefits with its potential dangers. For further details, healthcare professionals can consult resources like the NIH website.

Frequently Asked Questions

The primary danger is that tranexamic acid, by preventing clot breakdown, can worsen an existing clotting condition. This can lead to severe and potentially fatal thromboembolic events such as a pulmonary embolism or stroke.

TXA is contraindicated in subarachnoid hemorrhage because it can increase the risk of cerebral edema and infarction. Evidence has shown it does not improve outcomes in these patients and may increase the risk of harmful complications.

Yes, tranexamic acid can cause visual disturbances, including changes in color vision. For this reason, it is contraindicated in patients with acquired defective color vision, and regular eye exams are recommended for those on long-term treatment.

Tranexamic acid is primarily excreted by the kidneys. In patients with renal impairment, the drug can accumulate to toxic levels. Therefore, a reduced dose is required, and use in severe renal impairment should be done with extreme caution.

Combined use of tranexamic acid and combined hormonal contraceptives may increase the risk of thromboembolic events. It is often recommended to use an alternative, non-hormonal birth control method while on TXA.

A patient with a history of seizures is at an increased risk of TXA-induced seizures, especially with high doses. The provider should monitor the patient closely and consider discontinuing the drug if seizures occur.

Topical application of TXA results in minimal systemic absorption, so the systemic risks are lower. However, a history of hypersensitivity to TXA remains a contraindication regardless of the route of administration.