Tranexamic acid (TXA) is a medication used to prevent and control excessive bleeding by stabilizing blood clots. As an antifibrinolytic agent, it works by inhibiting the breakdown of fibrin, the protein that forms the structure of blood clots. It is prescribed for various conditions, including heavy menstrual bleeding (menorrhagia), nosebleeds (epistaxis), and managing blood loss during surgery or trauma. While effective, many patients wonder about its side effect profile. One of the most frequently asked questions is, "Can tranexamic acid cause headaches?" The answer, supported by extensive clinical evidence, is yes.
The Link Between Tranexamic Acid and Headaches
Evidence and Prevalence
Clinical studies and post-marketing surveillance consistently show headaches as a common side effect of tranexamic acid. The FDA label lists headache as a potential neurological symptom. For Lysteda, a TXA brand for heavy menstrual bleeding, headache is very common, reported in over 50% of participants in one study. A 2018 study linking a patient's headache and back pain to TXA reported a 50.4% incidence of headache.
Severity and Characteristics
Tranexamic acid-induced headache severity varies. Some experience mild headaches that may improve, while others have severe, throbbing ones. Headaches can occur alone or with nausea, dizziness, or muscle pain. The risk of headache may depend on the dose, with higher doses potentially increasing the likelihood.
The Neurological Mechanisms Behind TXA-Induced Headaches
The exact cause is not fully clear, but research suggests TXA interacts with central nervous system neurotransmitters. One proposed mechanism involves inhibiting inhibitory neurotransmitters.
GABAA and Glycine Receptor Antagonism
Tranexamic acid is an antagonist at GABAA and glycine receptors, which are key inhibitory neurotransmitters. Blocking these receptors can increase neuronal excitability. While high doses can cause severe issues like seizures, clinical doses are thought to contribute to pain and headaches. This effect in the spinal dorsal horn, involved in pain processing, might explain how TXA causes pain, including headaches.
Increased Neuronal Excitability
By reducing GABA and glycine signaling, TXA increases nervous system excitability. This heightened activity in pain-sensitive brain areas could lead to headaches. Animal studies support this by showing TXA increases neuron activity and excitatory transmission.
Common Side Effects Beyond Headaches
Besides headaches, tranexamic acid can cause other side effects:
- Nausea and vomiting
- Diarrhea and abdominal pain
- Back, joint, and muscle pain
- Nasal and sinus symptoms
- Tiredness or fatigue
- Dizziness
- Fever or chills
Report any bothersome symptoms to your doctor.
Managing Tranexamic Acid-Induced Headaches
Most TXA-related headaches are manageable:
- Evaluate Severity: Determine if the headache is mild or severe.
- OTC Pain Relievers: For mild headaches, your doctor may recommend acetaminophen or ibuprofen.
- Stay Hydrated: Drink plenty of fluids.
- Prioritize Sleep: Get enough rest.
- Relaxation Techniques: Try stress-management methods like deep breathing.
- Dose Adjustment: Your doctor might lower the TXA dose.
- Alternative Medications: For severe, persistent headaches, another antifibrinolytic like aminocaproic acid may be considered.
- Discontinuation: If other methods fail and the headache is severe, stopping the medication might be necessary.
Who Is at Higher Risk?
People with a history of migraines may be more prone to TXA-induced headaches. Combining TXA with other headache-causing medications can have additive effects. Discuss risks with your doctor if you have neurological conditions.
Tranexamic Acid vs. Placebo: A Comparison of Side Effects
| Side Effect | Tranexamic Acid (TXA) | Placebo | Notes |
|---|---|---|---|
| Headache | Very Common (e.g., >50%) | Experienced, but at a significantly lower rate than TXA | TXA patients show a much higher incidence of headache compared to those on placebo. |
| Back Pain | Common (e.g., >20%) | Experienced, but at a significantly lower rate | Often reported alongside headaches in TXA-treated patients. |
| Nasal & Sinus Symptoms | Common (e.g., >25%) | Reported at a much lower rate | Includes congestion, runny nose, and sinus pain. |
| Abdominal Pain | Common (e.g., >20%) | Reported at a similar rate to placebo, sometimes higher | Patients with menorrhagia may experience increased abdominal pain. |
| Nausea | Common | Less common | A frequently reported side effect of oral TXA. |
When to Seek Medical Attention
Seek immediate medical help if you have a severe headache along with any of the following:
- Sudden, severe headache
- Changes in eyesight or eye pain
- Signs of a blood clot (chest pain, shortness of breath, leg pain/swelling)
- Sudden dizziness or fainting
- Weakness on one side of the body
- Difficulty speaking or confusion
Stop taking the medication and contact your doctor or seek emergency help immediately.
Conclusion
Headaches are a common and well-documented side effect of tranexamic acid, supported by clinical evidence. They are thought to be caused by TXA's effect on inhibitory neurotransmitter receptors in the brain, increasing neuronal excitability and pain sensitivity. Mild headaches can often be managed with lifestyle adjustments or OTC pain relievers. However, severe or persistent headaches, especially with other serious symptoms, require immediate medical attention. Always discuss potential side effects and management with a healthcare provider.
