In a 51-year-old female with anemia and heavy menstrual bleeding who has not undergone a transvaginal ultrasound, what are the contraindications to prescribing tranexamic acid (TXA)?

Contraindications to Tranexamic Acid for Heavy Menstrual Bleeding

You can safely prescribe tranexamic acid (TXA) to this patient, but first screen for active thrombosis, history of thromboembolic events, renal impairment, subarachnoid hemorrhage, seizure history, and hypersensitivity to TXA. 1

Absolute Contraindications

Based on FDA labeling, do not prescribe TXA if your patient has 1:

• Active intravascular clotting (active DVT, PE, or arterial thrombosis)
• History of subarachnoid hemorrhage (risk of cerebral edema and infarction)
• Known hypersensitivity to tranexamic acid

Critical Screening Questions Before Prescribing

Thromboembolic Risk Assessment

Ask specifically about 1:

• Personal history of blood clots (DVT, PE, stroke, MI)
• Current use of hormonal contraceptives (combined oral contraceptives increase thrombosis risk when used with TXA)
• Current use of Factor IX concentrates or anti-inhibitor coagulant concentrates
• Family history of thrombophilia

Important caveat: While U.S. labeling lists "history of thrombosis or intrinsic risk for thrombosis" as contraindications, recent Danish registry data showed the absolute risk is low—number needed to harm for venous thromboembolism was 78,549 women per 5-day treatment course 2. The adjusted incidence rate ratio was 4.0 for VTE, but baseline rates were extremely low (11.8 vs 2.5 per 10,000 person-years).

Renal Function

Check serum creatinine 1:

• If creatinine 1.36-2.83 mg/dL: reduce to 10 mg/kg twice daily
• If creatinine 2.83-5.66 mg/dL: reduce to 10 mg/kg once daily
• If creatinine >5.66 mg/dL: reduce to 10 mg/kg every 48 hours

Neurological History

Screen for 1:

• History of seizures (TXA can cause focal and generalized seizures)
• Current dizziness or balance issues (TXA may worsen dizziness)

Practical Prescribing Approach

For this 51-year-old woman with HMB and anemia 3:

1. Prescribe TXA immediately while awaiting transvaginal ultrasound—you don't need imaging results to start treatment 3

2. Standard dosing: 1.3 g (two 650 mg tablets) three times daily for up to 5 days during menstruation 4, 5

3. Consider combination therapy: TXA plus iron supplementation for her anemia 6, 7. Recent evidence shows TXA combined with hormonal therapy (if not contraindicated) is most effective 7

4. Avoid concurrent hormonal contraceptives initially unless thrombotic risk is thoroughly assessed, as this combination increases VTE risk 1

Common Pitfalls to Avoid

• Don't delay TXA while waiting for imaging—structural pathology doesn't contraindicate TXA 3
• Don't assume all hormonal therapies are contraindicated with TXA—progesterone-only options are safer than combined estrogen-progestin 6
• Don't forget to address iron deficiency—52% of young women with HMB have iron deficiency, often requiring IV iron 7
• Don't prescribe beyond 5 days per cycle—longer duration hasn't been studied and may increase thrombotic risk 4

When to Refer

Arrange multidisciplinary consultation if 3:

• TXA fails after 2-3 cycles
• She requires ongoing anticoagulation (different risk-benefit calculation)
• Severe anemia requiring transfusion
• Suspected underlying bleeding disorder

The evidence strongly supports TXA as first-line therapy for HMB 4, 5, 8, with Australian data showing 12% annual increase in appropriate TXA prescribing 8. Your clinical judgment to start TXA before imaging is evidence-based and appropriate.