Short answer: In the label's placebo-controlled heavy-period trials, the most common side effects of Lysteda (tranexamic acid 3900 mg/day) were headache (50.4% vs 46.8% on placebo), nasal and sinus symptoms (25.4% vs 17.3%), back pain (20.7% vs 15.1%), abdominal pain (19.8% vs 18.0%) and muscle pain (11.2% vs 2.9%). It has no boxed warning; its main warnings are blood clots, eye problems and severe allergic reactions.
What Lysteda is approved for: Tranexamic acid tablets are an antifibrinolytic (a medicine that slows the breakdown of blood clots) approved to treat cyclic heavy menstrual bleeding in females of reproductive potential (section 1). Lysteda has no current brand-name label on DailyMed; this page uses the current label for the same 650 mg product under the Lysteda application (NDA 022430), sold by Nordic Pharma as tranexamic acid tablets.
Source
Tranexamic acid tablets, USP 650 mg (NDA 022430, the Lysteda product), prescribing information. Nordic Pharma. DailyMed, version published November 17, 2025. DailyMed setid 031bf7c2-3b07-469d-bc5a-31fc6238e25f
No. The current Lysteda label has no boxed warning.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Lysteda.
| Adverse reaction | Tranexamic acid 3900 mg/day n (%) N=232 | Placebo n (%) N=139 |
|---|---|---|
| Number of Subjects with at Least One Adverse Reaction | 208 (89.7%) | 122 (87.8%) |
| Headache (includes tension headache) | 117 (50.4%) | 65 (46.8%) |
| Nasal & sinus symptoms | 59 (25.4%) | 24 (17.3%) |
| Back pain | 48 (20.7%) | 21 (15.1%) |
| Abdominal pain | 46 (19.8%) | 25 (18.0%) |
| Musculoskeletal pain | 26 (11.2%) | 4 (2.9%) |
| Arthralgia (joint pain) | 16 (6.9%) | 7 (5.0%) |
| Muscle cramps & spasms | 15 (6.5%) | 8 (5.8%) |
| Migraine | 14 (6.0%) | 8 (5.8%) |
| Anemia | 13 (5.6%) | 5 (3.6%) |
| Fatigue | 12 (5.2%) | 6 (4.3%) |
Reactions reported by 5% or more of women on tranexamic acid 3900 mg/day and more often than on placebo, from two double-blind trials of 3 and 6 cycles. Women using hormonal contraception were excluded.
In a long-term open-label study of up to 27 cycles (781 women), 12.4% withdrew because of adverse reactions; in a 9-cycle extension study (288 women), 2.1% withdrew. Types and severity of reactions were similar to the controlled trials.
One woman in the extension trial had a severe allergic reaction in her fourth cycle, with shortness of breath, throat tightening and facial flushing that needed emergency treatment.
Reported after approval: impaired color vision and other visual disturbances, nausea, vomiting, diarrhea, anaphylactic shock, dizziness, allergic skin reactions, and blood clots including deep vein thrombosis, pulmonary embolism, brain clots and retinal artery and vein blockage, some with combined hormonal contraceptives.
Menstrual blood loss fell 39% on 3900 mg/day vs 5% on placebo in the 3-cycle study (Table 4), and 38% vs 12% in the 6-cycle study (Table 6).
Reported overdose symptoms with tranexamic acid include nausea, vomiting, diarrhea, dizziness on standing, blood clots, vision problems, mental status changes, muscle jerks and rash.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Blood clots, including in the eye. Venous and arterial clots and blockage of retinal arteries and veins have been reported. Anyone with eye or vision symptoms stops the tablets right away and is referred to an eye doctor for a full exam, including a dilated retinal exam.
Combined hormonal contraceptives. Taking tranexamic acid with a combined estrogen-and-progestin contraceptive may further raise the risk of clots, stroke and heart attack, especially with obesity or smoking and in smokers over 35. This combination is contraindicated.
Clotting factor products and tretinoin. Not recommended with Factor IX complex concentrates or anti-inhibitor coagulant concentrates, or in acute promyelocytic leukemia treated with all-trans retinoic acid (oral tretinoin), because clotting risk may rise.
Severe allergic reactions. A severe allergic reaction occurred in a clinical trial, and anaphylactic shock has been reported with IV tranexamic acid. It is contraindicated with known allergy to tranexamic acid.
Subarachnoid hemorrhage. Brain swelling and stroke may be caused by tranexamic acid in people with bleeding around the brain (subarachnoid hemorrhage).
Ligneous conjunctivitis. A rare thick, woody inflammation of the eye lining has been reported, and it cleared after stopping tranexamic acid.
Who should not take it. Women using combined hormonal contraception, and anyone with active clots or a history or built-in risk of clots, including retinal vein or artery blockage, clot-prone heart valve or rhythm disease, or a clotting disorder.
From the Patient Information that comes with Lysteda:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.