Can tranexamic acid (TXA) stop a lower gastrointestinal (GI) bleed?

Tranexamic Acid for Lower GI Bleeding

Tranexamic acid (TXA) is not recommended for the routine management of lower gastrointestinal bleeding as current evidence does not support its effectiveness in this specific condition. 1, 2

Evidence Assessment

Efficacy in Lower GI Bleeding

• The most recent and highest quality evidence from a 2024 double-blind randomized controlled trial showed that intravenous TXA had no significant effect on blood transfusion requirements in patients with lower GI bleeding 1
• This finding is consistent with a 2018 randomized placebo-controlled trial which demonstrated that TXA did not decrease blood loss or improve clinical outcomes in patients with lower GI bleeding 2

Contrast with Upper GI Bleeding

• While TXA has shown efficacy in upper GI bleeding, with meta-analyses showing reduced rates of continued bleeding, urgent endoscopic intervention, and mortality compared to placebo 3, this benefit has not been demonstrated for lower GI bleeding
• The British Society of Gastroenterology guidelines specifically state that "at this time we suggest that use of tranexamic acid in acute LGIB is confined to clinical trials" 4

Management Algorithm for Lower GI Bleeding

Initial Assessment and Resuscitation

1. Hemodynamic stabilization is the priority
   • Fluid resuscitation if unstable
   • Transfusion support with a recommended threshold of 70 g/L, aiming for 70-100 g/L 4
   • Higher threshold (>70 g/L) should be considered in patients with cardiovascular disease

Diagnostic Approach

1. For hemodynamically unstable patients or those with shock index >1:

   • CT angiography is recommended as the fastest and least invasive means to localize bleeding 4
   • Consider upper GI endoscopy if no source is identified on CTA, as 10-15% of apparent lower GI bleeds are actually from upper GI sources 4

2. For stable patients:

   • Colonoscopy within 24 hours after adequate bowel preparation 5

Therapeutic Options

1. Endoscopic therapy for high-risk stigmata (active bleeding, non-bleeding visible vessel, adherent clot) 5
2. Radiographic interventions (angiography with embolization) for ongoing bleeding not responding to other measures
3. Medication management:
   • Interrupt direct oral anticoagulants at presentation 4
   • Consider reversal agents (idarucizumab or andexanet) for life-threatening hemorrhage in patients on DOACs 4
   • Restart anticoagulation approximately 7 days after hemorrhage if safe 4

Special Considerations

Anticoagulation Management

• DOACs should be interrupted at presentation with lower GI bleeding 4
• For severe life-threatening hemorrhage on DOACs, specific reversal agents should be considered:
  • Idarucizumab for dabigatran
  • Andexanet alfa for factor Xa inhibitors (apixaban, rivaroxaban, edoxaban) 4

Pitfalls to Avoid

1. Assuming all rectal bleeding is from a lower GI source

   • Up to 15% of apparent lower GI bleeds originate from upper GI sources 4
   • Consider upper endoscopy in patients with hemodynamic instability

2. Inappropriate use of TXA

   • Despite its effectiveness in trauma and upper GI bleeding, current evidence does not support routine use in lower GI bleeding 4, 1, 2
   • Reserve TXA use for clinical trials or exceptional circumstances (such as patients refusing blood products) 6

3. Delayed colonoscopy

   • Colonoscopy should be performed within 24 hours after adequate bowel preparation for optimal diagnostic and therapeutic yield 5

In summary, while TXA has proven benefits in other bleeding conditions, the current evidence does not support its routine use for lower GI bleeding. Management should focus on appropriate resuscitation, timely diagnostic procedures, and targeted interventions based on the identified source of bleeding.