Tranexamic Acid Dosage for Adults with Normal Renal Function
For an adult patient with normal renal function and no bleeding disorders, administer tranexamic acid as a 1 g intravenous loading dose over 10 minutes, followed by a 1 g infusion over 8 hours. 1, 2
Standard Dosing Protocol
Loading Dose
- Administer 1 g (1000 mg) intravenously over 10 minutes as the initial loading dose 1, 3, 4
- Infuse no faster than 1 mL/minute to avoid hypotension 2
- This fixed-dose regimen is supported by the landmark CRASH-2 trial, which demonstrated a 9% relative risk reduction in all-cause mortality 1, 5
Maintenance Dose
- Follow with 1 g intravenous infusion over 8 hours 1, 3, 6
- This achieves therapeutic plasma levels of approximately 10 μg/mL required to inhibit fibrinolysis 5
- The plasma half-life is approximately 120 minutes in patients with normal renal function 1, 7
Critical Timing Considerations
Tranexamic acid must be administered within 3 hours of bleeding onset for maximum mortality benefit. 1, 3
- Administration within 1 hour significantly reduces mortality due to bleeding (relative risk 0.68) 1
- Treatment between 1-3 hours still provides benefit (relative risk 0.79) 1
- Administration after 3 hours may paradoxically increase risk of death (relative risk 1.44) and is not recommended 1, 3
- Effectiveness decreases by 10% for every 15-minute delay 3
Alternative Weight-Based Dosing
For specific surgical contexts (particularly cardiac surgery), weight-based dosing may be used:
- Loading dose: 10 mg/kg actual body weight intravenously 2, 8
- Maintenance infusion: 1-5 mg/kg/hour continuous infusion 5
- This achieves similar therapeutic plasma concentrations as the fixed-dose regimen 5, 8
Maximum Safe Dosing
- Do not exceed 100 mg/kg total dose in any 24-hour period to minimize seizure risk 5, 3
- Doses exceeding this threshold are associated with significantly increased seizure risk, particularly in patients over 50 years of age 5, 3
- For trauma and major bleeding, the maximum recommended total dose is 2 grams (1 g loading + 1 g maintenance) 5
Route of Administration
- Intravenous administration only - this is the only FDA-approved and evidence-based route for acute hemorrhage 3, 2
- Tranexamic acid must never be administered intrathecally, as this can cause seizures and cardiac arrhythmias 2
- Clearly label syringes with "INTRAVENOUS USE ONLY" to prevent medication errors 2
Mechanism of Action
- Tranexamic acid is a synthetic lysine analogue that competitively inhibits plasminogen activation 1, 7, 4
- This prevents conversion of plasminogen to plasmin, thereby reducing fibrinolysis and decreasing bleeding 7, 6
- The drug is distributed throughout all tissues with therapeutic effects lasting several hours 1
Safety Considerations and Contraindications
Absolute Contraindications
- Subarachnoid hemorrhage - risk of cerebral edema and infarction 3, 2
- Active intravascular clotting 2
- Severe hypersensitivity to tranexamic acid 2
Monitoring and Precautions
- Monitor for thromboembolic events, particularly in elderly patients 7
- Avoid concomitant use with prothrombotic agents (Factor IX concentrates, hormonal contraceptives) as this increases thrombotic risk 2
- Watch for seizures, especially with high doses or inadvertent neuraxial administration 2
- Discontinue immediately if visual disturbances occur 2
Common Pitfalls to Avoid
- Do not delay administration - every 15 minutes of delay reduces effectiveness by 10% 3
- Do not give after 3 hours from injury/bleeding onset - this may worsen outcomes 1, 3
- Do not exceed maximum dosing - total doses >100 mg/kg significantly increase seizure risk 5, 3
- Do not confuse routes - intravenous only; never intrathecal 2
- Do not use in subarachnoid hemorrhage - this is an absolute contraindication 3, 2