Management of Bromadiolone Poisoning
Treat bromadiolone poisoning with high-dose vitamin K1 (phytomenadione) guided by INR monitoring, with treatment duration extending weeks to months due to the extremely long half-life of this second-generation anticoagulant rodenticide.
Initial Assessment and Diagnosis
Bromadiolone is a "superwarfarin" with a biphasic elimination pattern: an initial rapid decline phase (half-life 3.5 days) followed by a prolonged terminal phase (half-life 24 days) 1. This prolonged elimination necessitates extended treatment compared to warfarin poisoning.
Key diagnostic steps:
- Measure INR/PT at 36-48 hours post-exposure, even if asymptomatic 2
- Obtain baseline coagulation studies (PT, aPTT, INR)
- Consider serum bromadiolone level measurement if available (though not routinely necessary for management)
- Assess for active bleeding (skin/mucosa, GI tract, urinary tract, or CNS hemorrhage) 3
Treatment Algorithm
For Active Bleeding with Elevated INR
Immediate reversal is critical - following the VKA bleeding management principles:
- Stop any anticoagulant exposure
- Administer prothrombin complex concentrate (PCC): 25-50 IU/kg (preferred over fresh frozen plasma) 4
- Give vitamin K1 (phytomenadione) 10 mg IV (or 100 mcg/kg for children) 2
- Check INR within 30 minutes, then at 6-8 hours and 24 hours 4
- Administer additional PCC/vitamin K if INR remains elevated based on repeat measurements
For life-threatening hemorrhage (e.g., intracranial bleeding), target INR <1.2; for other severe bleeding, target INR <1.5 4.
For Elevated INR Without Active Bleeding
- Administer vitamin K1 10 mg orally or IV 2
- Monitor INR at 24 hours and adjust vitamin K dosing accordingly 4
- Continue monitoring every 48-72 hours until two consecutive INRs are within therapeutic range 4
For Asymptomatic Exposure with Normal INR
- If INR measured at 36-48 hours is normal, no treatment required 2
- Do not administer prophylactic vitamin K or PCC 4
- This applies even to long-acting anticoagulant rodenticides if the INR remains normal at this timepoint
Long-Term Management
Critical pitfall: Bromadiolone requires prolonged vitamin K1 therapy lasting weeks to months, far exceeding typical warfarin reversal 1, 2.
Treatment duration guidance:
- Continue oral vitamin K1 (typically 25-50 mg daily in divided doses for adults)
- Monitor INR regularly (every 2-3 days initially, then weekly)
- Do not discontinue vitamin K based solely on INR normalization - this is insufficient 5
- Ideally, measure serum bromadiolone levels; treatment should continue until levels are <10 ng/mL 5, 1
- If serum levels unavailable, continue vitamin K for at least 4-6 weeks after large ingestions, with careful INR monitoring
Monitoring strategy:
- Check INR 48-72 hours after stopping vitamin K to detect rebound coagulopathy 5
- Resume vitamin K if INR rises above therapeutic range
- Patients may require treatment for 3-6 months in severe cases 2
Special Considerations
CNS hemorrhage risk: Bromadiolone can cause subarachnoid hemorrhage and intracerebral hematoma, which are rare but potentially lethal complications 3. Maintain high clinical suspicion for neurological symptoms (headache, lethargy, altered mental status).
Pediatric exposures: Young children with small accidental ingestions rarely develop coagulopathy and do not require routine INR monitoring unless the ingestion was substantial 2.
Activated charcoal: May be considered if presentation is within 8 hours of ingestion, though evidence is limited for rodenticides specifically 4.
The key distinction from warfarin poisoning is the dramatically prolonged treatment course required due to bromadiolone's long half-life and tissue accumulation. Premature discontinuation of vitamin K therapy based on normalized INR alone is a common error that can lead to recurrent coagulopathy and repeated hospitalizations 5.