Can tranexamic acid be harmful? Understanding the Risks and Side Effects

October 14, 2025 •

3 min read

Tranexamic acid (TXA) is a World Health Organization essential medicine that has been saving lives by reducing bleeding in trauma and postpartum hemorrhage. However, as with any potent medication, the question arises: Can tranexamic acid be harmful? The answer is yes, if used incorrectly or in contraindicated patient populations.

Quick Summary

Tranexamic acid can cause harm, primarily through a rare but serious increased risk of thromboembolic events (blood clots) and seizures, especially with high doses or in susceptible individuals. Other concerns include potential visual disturbances and allergic reactions.

Key Points

Risk of Blood Clots: Tranexamic acid can increase the risk of venous and arterial thrombosis, particularly in patients with pre-existing clotting disorders, a history of blood clots, or those using hormonal birth control.
Seizure Potential: High-dose intravenous administration or use in patients with kidney dysfunction carries a risk of seizures due to the drug's effect on neurotransmitters in the brain.
Visual Side Effects: Long-term use requires ophthalmic monitoring, as tranexamic acid can cause vision changes, including potential color vision defects or retinal issues.
Contraindicated Conditions: The medication should not be used in patients with active intravascular clotting, subarachnoid hemorrhage, or known hypersensitivity.
Importance of Early Administration: In acute trauma, the efficacy and safety profile of tranexamic acid are optimized with early administration (within three hours), with potential harm if delayed.
Common vs. Serious Side Effects: While mild side effects like nausea and headache are common, serious risks like thromboembolic events and seizures are rare but require immediate medical attention.

Tranexamic acid (TXA) is a synthetic antifibrinolytic agent used to prevent excessive bleeding by inhibiting the breakdown of fibrin, a key component of blood clots. This mechanism makes it valuable in various medical situations, including trauma and heavy menstrual bleeding. While beneficial, TXA also has risks and side effects that require medical oversight.

The Dual Nature of Clotting: Benefit vs. Risk

By stabilizing blood clots, TXA is effective in treating excessive bleeding. Studies have shown it reduces mortality in trauma and postpartum hemorrhage when administered promptly. However, this same action can increase the risk of unwanted clotting, leading to dangerous thromboembolic events.

Serious Risks and Adverse Reactions

Thromboembolic Events (Blood Clots)

The most significant potential harm from TXA is an increased risk of blood clots, including Deep Vein Thrombosis (DVT), Pulmonary Embolism (PE), stroke, or heart attack. This risk is higher in individuals with a history of clots, those on combined hormonal contraceptives, or those with conditions that increase clotting risk.

Seizures

A less common but serious risk is seizures, particularly with high intravenous doses or in patients with kidney problems. This is thought to be due to TXA's effect on brain receptors. Patients with seizure history or kidney impairment need careful monitoring.

Visual Disturbances

High doses or long-term use of TXA may cause visual changes, including effects on color vision. For treatment lasting over three months, regular eye exams are recommended, and the drug should be stopped if vision changes occur.

Allergic Reactions

Allergic reactions, from mild rashes to severe anaphylaxis, can happen. Signs of a serious reaction, such as breathing difficulties or swelling, require immediate medical attention.

Contraindications and Risk Factors

TXA is not suitable for everyone. Contraindications include active blood clotting, known allergy to TXA, a history of subarachnoid hemorrhage, and concurrent use of combined hormonal contraceptives due to increased clot risk. Factors requiring caution include kidney issues, seizure history, being over 35 and a smoker while using hormonal birth control.

Comparison of Risk Factors

The risks associated with TXA vary depending on the context of use. The table below outlines relative risks in different scenarios.


Feature	Heavy Menstrual Bleeding (Oral)	Trauma Hemorrhage (IV, Early)	Intracranial Bleeding	High-Dose Cardiac Surgery (IV)
Thrombotic Risk	Low, but contraindicated with hormonal contraceptives.	No significant increase in occlusive events with early dosing.	Increased risk; generally not recommended.	Some studies suggest higher risk due to surgical factors.
Seizure Risk	Very low.	Very low with standard doses.	High risk due to crossing the blood-brain barrier.	Highest risk with higher doses.
Visual Disturbance	Possible with long-term use; monitoring advised.	Unlikely with acute use.	Low likelihood with acute use.	Low likelihood with acute use.
Kidney Concerns	Dose adjustment needed for renal impairment.	Dose adjustment needed for renal impairment.	Dose adjustment needed for renal impairment.	Dose adjustment needed for renal impairment.

Administration and Monitoring

Safe TXA use involves correct administration, such as slow intravenous infusion to avoid low blood pressure. In trauma, early use within three hours is most effective and potentially less harmful than delayed administration. Dose adjustments are essential for patients with kidney disease because the kidneys excrete TXA.

Conclusion: Balancing Benefit and Harm

Tranexamic acid is a valuable medication for controlling excessive bleeding, particularly in acute situations like trauma and postpartum hemorrhage. Its safety is generally good when used correctly. However, risks like blood clots and seizures, though rare, are serious, especially with higher doses or in susceptible individuals. Safe use depends on choosing appropriate patients, using correct dosages, and monitoring for adverse effects. TXA should not be given to patients with contraindications like a history of blood clots or those using certain hormonal contraceptives. By understanding these risks, healthcare providers can maximize TXA's benefits while minimizing harm. For more on drug safety, refer to the World Health Organization (WHO) drug safety page.

Frequently Asked Questions

The main risk of taking tranexamic acid is the potential for an increased risk of blood clots, or thromboembolic events, especially in individuals with a history of clotting problems or who are on hormonal birth control.

Yes, tranexamic acid has been known to cause seizures, particularly when administered in high doses or to patients with renal impairment. The risk is higher in the context of certain surgeries, like cardiac procedures.

You should stop taking the medication and contact your doctor immediately if you experience any changes in your vision, such as blurriness or difficulty seeing colors. Long-term users should receive regular ophthalmic exams.

Tranexamic acid is contraindicated for patients with active intravascular clotting, a history of subarachnoid hemorrhage, or known hypersensitivity to the drug. It should also be avoided by those using combined hormonal contraceptives.

Yes, hypersensitivity reactions, including severe anaphylaxis, are possible with tranexamic acid. Symptoms like difficulty breathing, hives, or swelling of the face require immediate emergency medical care.

Yes, especially in trauma cases. Studies show that administering tranexamic acid within three hours of a traumatic injury is most effective and safe. Use outside this window or in delayed scenarios may be less effective and potentially harmful.

While tranexamic acid is eliminated by the kidneys, it does not typically cause kidney damage. However, patients with pre-existing kidney impairment require a reduced dosage, as slower elimination can lead to toxic levels of the medication.