What investigations are necessary before starting tranexamic acid (TXA) for melasma in an otherwise healthy patient?

Pre-Treatment Screening for Tranexamic Acid in Melasma

For an otherwise healthy 35-year-old woman starting oral tranexamic acid for melasma, screen for personal and family history of thromboembolic events and contraindications, but no routine laboratory investigations are necessary unless risk factors are identified.

Essential Clinical Screening

Thromboembolic Risk Assessment

• Screen carefully for personal history of venous or arterial thrombosis, pulmonary embolism, deep vein thrombosis, stroke, or any thromboembolic events 1, 2
• Obtain detailed family history of thrombophilia, clotting disorders (such as protein S or protein C deficiency, Factor V Leiden), or unexplained thromboembolic events in first-degree relatives 2
• Document current use of hormonal contraceptives, as tranexamic acid is contraindicated with concomitant use of pro-thrombotic medications including hormonal contraceptives 1
• One case report documented deep vein thrombosis in a patient who was later diagnosed with familial protein S deficiency, highlighting the critical importance of family history screening 2

Absolute Contraindications to Identify

• Active intravascular clotting or history of thromboembolic disease 1
• History of hypersensitivity or anaphylactic reactions to tranexamic acid 1
• Current use of hormonal contraceptives or other pro-thrombotic medications (Factor IX Complex concentrates, Anti-inhibitor Coagulant concentrates) 1
• History of seizure disorders 1

Additional Clinical History

• Screen for renal impairment history, as dose adjustments are required for moderate to severe renal dysfunction 1
• Document history of visual disturbances or retinal disease 1
• Assess for pregnancy or breastfeeding status 1

Laboratory Investigations

When No Risk Factors Present

• No routine laboratory testing is required for an otherwise healthy patient without identified risk factors 3, 2
• The literature does not support routine coagulation studies, complete blood counts, or thrombophilia screening in asymptomatic patients without personal or family history 3, 2

When Risk Factors Are Identified

• If family history of thrombophilia or unexplained thromboembolic events exists, consider thrombophilia screening including protein S, protein C, antithrombin III, Factor V Leiden, and prothrombin gene mutation 2
• If renal disease history or risk factors present, obtain serum creatinine to guide dosing adjustments 1

Ophthalmologic Monitoring Considerations

• Baseline ophthalmologic examination is NOT required for treatment initiation 1
• Consider ophthalmologic monitoring (visual acuity and optical coherence tomography) only if treatment is expected to exceed 3 months duration 1
• Animal studies showed retinal degeneration at high doses, but no retinal changes have been observed in humans treated for up to 8 years 1

Common Pitfalls to Avoid

• Failing to ask specifically about family history of clotting disorders—this is the most critical screening element that identified the one serious adverse event in a large retrospective study of 561 patients 2
• Not documenting hormonal contraceptive use, which is an absolute contraindication to concurrent tranexamic acid therapy 1
• Ordering unnecessary baseline coagulation studies in low-risk patients, which adds cost without evidence of benefit 3, 2

Treatment Protocol After Clearance

• Standard dosing is 250 mg twice daily for 12 weeks, with response typically seen within 2 months 3, 4, 5, 6
• Adverse events occur in approximately 7% of patients and are typically mild and transient (epigastric discomfort, hypomenorrhea, headache) 5, 2
• Relapse rates are approximately 27% after discontinuation, so maintenance therapy may be necessary 2