Bromadiolone poisoning is an important cause of potentially severe and prolonged bleeding because bromadiolone is a long-acting anticoagulant rodenticide (LAAR), commonly called a superwarfarin. It inhibits vitamin K recycling and consequently reduces the activity of vitamin K–dependent coagulation factors II, VII, IX and X.

Unlike ordinary warfarin exposure, bromadiolone poisoning may produce prolonged coagulopathy lasting weeks to months, and patients may require prolonged treatment with vitamin K1 (phytomenadione) and repeated INR monitoring.

Clinical pearl: A patient can appear clinically well initially and subsequently develop severe coagulopathy. A normal INR early after exposure does not necessarily exclude clinically important toxicity.

What is Bromadiolone?

Bromadiolone is a second-generation 4-hydroxycoumarin anticoagulant rodenticide. It belongs to the long-acting anticoagulant rodenticide group along with compounds such as brodifacoum and difenacoum.

It is considerably more persistent than conventional warfarin and can produce prolonged suppression of vitamin K–dependent coagulation.

Mechanism of bromadiolone poisoning

Bromadiolone inhibits vitamin K epoxide reductase, preventing regeneration of active vitamin K.

This results in impaired γ-carboxylation and activation of:

Factor II
Factor VII
Factor IX
Factor X
Protein C
Protein S

The result is progressive impairment of coagulation and an increased risk of spontaneous or trauma-related bleeding.

Clinical Features of Bromadiolone Poisoning

Patients may initially have no symptoms.

As coagulopathy develops, manifestations may include:

Epistaxis
Gingival bleeding
Easy bruising
Hematuria
Hematemesis
Melena
Hematochezia
Menorrhagia
Intramuscular bleeding
Hemarthrosis
Retroperitoneal bleeding
Intracranial hemorrhage
Hemoperitoneum
Severe anemia
Hemorrhagic shock

Intracranial hemorrhage is an uncommon but potentially life-threatening complication.

Initial Assessment

Management begins with stabilization and assessment of bleeding risk.

ABCDE assessment

A — Airway

Assess airway protection, particularly in patients with:

Altered consciousness
Intracranial hemorrhage
Massive upper gastrointestinal bleeding

B — Breathing

Assess:

Respiratory rate
Oxygen saturation
Respiratory distress

C — Circulation

Assess:

Heart rate
Blood pressure
Peripheral perfusion
Capillary refill
Evidence of active bleeding
Shock

Establish IV access and obtain blood samples early.

D — Disability

Assess:

Glasgow Coma Scale
Pupils
Focal neurological deficits
Headache
Seizures

Consider intracranial hemorrhage when neurological symptoms occur in a patient with severe coagulopathy.

E — Exposure

Look carefully for:

Bruising
Petechiae
Hematomas
Hematuria
Gastrointestinal bleeding
Injection or trauma sites

Investigations in Bromadiolone Poisoning

Important investigations include:

Essential tests

PT/INR
aPTT
CBC with platelet count
Hemoglobin/hematocrit
Blood group and crossmatch
Fibrinogen
Renal function
Liver function tests
Serum electrolytes

Additional tests when indicated

Factor II, VII, IX and X levels
Mixing study
Specific bromadiolone/superwarfarin assay
CT brain for neurological symptoms
Ultrasound/CT for suspected internal bleeding

Bromadiolone poisoning characteristically produces a vitamin K–dependent factor deficiency pattern, particularly involving factors II, VII, IX and X.

Bromadiolone Poisoning Treatment

The two major principles of treatment are:

Replace vitamin K1 to overcome the anticoagulant effect
Rapidly replace deficient coagulation factors when there is significant or life-threatening bleeding

1. Vitamin K1 — The Specific Antidote

Vitamin K1 (phytomenadione/phytonadione) is the cornerstone of treatment.

It restores the availability of reduced vitamin K and allows synthesis of functional vitamin K–dependent clotting factors.

Importantly, vitamin K does not immediately replace circulating clotting factors. Therefore, a patient with life-threatening hemorrhage may require coagulation-factor replacement in addition to vitamin K.

Route of vitamin K1

Depending on severity:

Oral vitamin K1 — useful for stable patients and prolonged treatment
IV vitamin K1 — preferred when rapid treatment is required or oral administration is not feasible

IV vitamin K should be administered cautiously because serious hypersensitivity/anaphylactoid reactions have been reported.

Vitamin K1 Dose in Bromadiolone Poisoning

There is no universally standardized dose or duration for bromadiolone poisoning.

The required dose depends on:

INR
Severity of coagulopathy
Presence or absence of bleeding
Amount/type of rodenticide exposure
Response to treatment
Recurrence of coagulopathy after dose reduction or interruption

Published cases have used a wide range of regimens, including repeated IV vitamin K followed by high-dose oral vitamin K.

For severe superwarfarin poisoning, high-dose vitamin K1 administered repeatedly throughout the day may be necessary, with dosing adjusted according to the INR and clinical response. Some toxicology literature reports doses as high as 50–100 mg/day or more in severe cases, but these doses should be individualized with toxicology/hematology guidance rather than applied as a routine dose.

Important

Do not use a single fixed vitamin K dose for every bromadiolone ingestion.

The appropriate regimen should be guided by:

Clinical bleeding + INR/PT response + toxicology consultation

2. Management of Active or Life-Threatening Bleeding

Vitamin K alone may be insufficient initially because the liver requires time to synthesize new coagulation factors.

For patients with major, life-threatening bleeding, rapid coagulation-factor replacement is required.

Options include:

4-factor PCC

4-factor prothrombin complex concentrate (PCC) provides factors:

and can rapidly correct severe vitamin K antagonist–associated coagulopathy.

Fresh Frozen Plasma

FFP can also replace deficient coagulation factors.

It may be used when PCC is unavailable or according to local protocol.

Packed RBCs

Packed red blood cells should be administered when significant blood loss has caused clinically important anemia or hemorrhagic shock.

The choice and dose of blood products should be individualized according to bleeding severity, hemoglobin, hemodynamic status and local transfusion protocols.

Key principle

Major bleeding = vitamin K1 + rapid coagulation-factor replacement + definitive control of the bleeding source.

3. Control the Source of Bleeding

Correction of coagulopathy is not enough if active bleeding continues.

Depending on the site, management may include:

Endoscopic hemostasis
Surgical intervention
Interventional radiology
Neurosurgical intervention
Local pressure
Gynecological intervention
Management of gastrointestinal bleeding

A published case of severe bromadiolone-associated intracranial/other hemorrhage illustrates the need for both correction of coagulopathy and definitive treatment of the bleeding source.

4. Activated Charcoal and Gastric Decontamination

Routine gastrointestinal decontamination is not the main treatment for established bromadiolone poisoning.

Evidence summarized in toxicology reviews indicates that multiple-dose activated charcoal has not demonstrated reliable benefit for superwarfarin poisoning.

Any consideration of activated charcoal after a recent ingestion should therefore be individualized according to:

Time since ingestion
Amount ingested
Airway protection
Toxicology advice
Product formulation

Do not delay resuscitation or treatment of hemorrhage for gastrointestinal decontamination.

5. INR Monitoring

INR is the most practical laboratory marker for monitoring the anticoagulant effect.

A patient with significant exposure should have serial:

PT/INR
aPTT
CBC
Hemoglobin

The frequency depends on the severity of poisoning and treatment response.

In severe poisoning, INR may need to be checked frequently during initial stabilization, followed by less frequent monitoring once a stable vitamin K regimen has been established.

Why Long-Term Treatment May Be Necessary

This is one of the most important differences between bromadiolone and ordinary warfarin poisoning.

Bromadiolone is highly lipophilic and has prolonged persistence in the body. Human pharmacokinetic data demonstrate a prolonged terminal elimination phase; one clinical study estimated a terminal half-life of approximately 24 days.

Therefore:

Stopping vitamin K too early → recurrent INR elevation → recurrent bleeding.

Cases have documented recurrence of severe coagulopathy after vitamin K was discontinued despite an initially normal INR.

When Can Vitamin K Be Stopped?

There is no universally accepted evidence-based stopping rule for bromadiolone poisoning.

A normal INR while the patient is receiving vitamin K does not necessarily mean that bromadiolone has been eliminated.

A commonly used approach is:

Stabilize the INR with vitamin K.
Continue vitamin K while the toxic effect persists.
Gradually reduce/taper treatment when appropriate.
Stop vitamin K under specialist supervision.
Recheck PT/INR approximately 48–72 hours after stopping vitamin K.
Restart treatment if significant coagulopathy recurs.

Where available, quantitative serum bromadiolone/superwarfarin testing can provide additional information, although there is no universally validated concentration threshold that independently determines when treatment can safely stop.

Bromadiolone Poisoning: Practical Treatment Algorithm

Suspected bromadiolone ingestion

↓

Assess ABCDE + bleeding

↓

Obtain PT/INR ± aPTT, CBC and other baseline investigations

↓

Is there major/life-threatening bleeding?

YES

→ Vitamin K1
→ 4-factor PCC or FFP for rapid factor replacement
→ RBC transfusion when indicated
→ Definitive control of bleeding
→ Serial INR monitoring
→ Toxicology/hematology consultation

→ Assess exposure and coagulation profile
→ Serial PT/INR monitoring
→ Vitamin K1 when clinically indicated
→ Continue monitoring because delayed/prolonged coagulopathy can occur

↓

INR controlled?

YES

→ Continue appropriately dosed vitamin K1
→ Regular INR monitoring
→ Gradual reduction when appropriate

→ Check adherence
→ Reassess ongoing exposure/re-exposure
→ Increase/adjust vitamin K under specialist guidance
→ Evaluate for ongoing bleeding

↓

Considering stopping vitamin K?

→ Stop only after adequate clinical assessment
→ Recheck INR after approximately 48–72 hours
→ Restart treatment if coagulopathy recurs

Bromadiolone Poisoning in Children

Children may accidentally ingest rodenticide bait.

A child who has ingested a small amount may remain asymptomatic, but the risk assessment depends on:

Exact product
Active ingredient
Concentration
Amount ingested
Child’s weight
Time since ingestion
Repeated versus single exposure

Do not automatically assume that every rodenticide product contains bromadiolone. The product label should be checked whenever possible.

For children with suspected anticoagulant rodenticide exposure, consultation with a poison center or medical toxicologist is recommended.

Important Differential Diagnoses

A markedly prolonged PT/INR should not automatically be attributed to bromadiolone.

Consider:

Warfarin exposure
Other anticoagulant rodenticides
Vitamin K deficiency
Liver disease
Disseminated intravascular coagulation
Acquired factor inhibitors
Congenital coagulation-factor deficiencies
Malabsorption
Drug interactions

Superwarfarin poisoning should particularly be considered in a patient with unexplained prolonged PT/INR and bleeding, especially when the history is unclear.

Key Differences: Warfarin vs Bromadiolone

Feature	Warfarin	Bromadiolone
Use	Therapeutic anticoagulant	Rodenticide
Class	Vitamin K antagonist	Long-acting vitamin K antagonist
Common name	Warfarin	Superwarfarin
Duration of effect	Usually shorter	Prolonged
Coagulopathy	Usually manageable over days	May persist weeks–months
Antidote	Vitamin K1	Vitamin K1
Severe bleeding	Factor replacement may be required	Factor replacement may be required
Long-term vitamin K	Sometimes	Frequently required in severe poisoning
Monitoring	INR	Serial INR/PT

Important Clinical Pearls

1. A normal early INR does not completely exclude toxicity.

The anticoagulant effect can be delayed because existing circulating clotting factors must first decline.

2. Vitamin K1 is the specific treatment.

Bromadiolone poisoning is fundamentally a vitamin K antagonist poisoning.

3. Vitamin K does not immediately correct major hemorrhage.

In life-threatening bleeding, rapidly replace coagulation factors with 4-factor PCC or FFP, according to availability and local protocol.

4. Treatment may last for months.

Severe bromadiolone poisoning can require prolonged vitamin K1 therapy because of its long persistence.

5. Do not stop vitamin K simply because the INR becomes normal.

The INR may normalize because of administered vitamin K while the rodenticide remains in the body.

6. Monitor after stopping therapy.

A recurrence of INR elevation after vitamin K withdrawal strongly suggests persistent anticoagulant activity.

7. Always identify the active ingredient.

“Rat poison” is not a diagnosis. Different rodenticides have different toxic mechanisms and treatments.

Summary

Bromadiolone poisoning is a potentially life-threatening superwarfarin poisoning characterized by prolonged vitamin K–dependent coagulopathy.

The cornerstone of treatment is:

Vitamin K1 + INR-guided monitoring + rapid factor replacement when significant bleeding is present.

Patients with severe poisoning may require high-dose and prolonged vitamin K1 therapy for weeks or months. Treatment should not be discontinued solely because the INR has normalized while the patient is receiving vitamin K. After vitamin K is eventually stopped, repeat coagulation testing after approximately 48–72 hours can help identify recurrent anticoagulation.

Because bromadiolone poisoning can be prolonged and potentially fatal, significant exposures, abnormal coagulation studies, or any active bleeding warrant urgent medical evaluation and specialist toxicology/hematology input.

Frequently Asked Questions

What is the antidote for bromadiolone poisoning?

Vitamin K1 (phytomenadione/phytonadione) is the specific antidote for bromadiolone-induced vitamin K antagonism.

How long does bromadiolone poisoning last?

Severe poisoning can persist for weeks to months, reflecting the prolonged persistence of bromadiolone and its anticoagulant effect.

Does bromadiolone poisoning cause bleeding?

Yes. Severe poisoning can cause epistaxis, gum bleeding, hematuria, gastrointestinal bleeding, internal hemorrhage and, rarely, intracranial hemorrhage.

Can bromadiolone poisoning be treated?

Yes. Early recognition, vitamin K1 therapy, appropriate coagulation-factor replacement and close monitoring can successfully reverse the coagulopathy.

Is vitamin K enough for severe bleeding?

Not necessarily. Vitamin K restores coagulation factor production but does not provide an immediate supply of functional factors. Patients with life-threatening bleeding may require 4-factor PCC or FFP in addition to vitamin K1.

Can bromadiolone poisoning recur after treatment?

Yes. Recurrent coagulopathy can occur after vitamin K is stopped because bromadiolone may remain active in the body for a prolonged period.

SEO Keywords

Primary keyword:
Bromadiolone poisoning treatment

Secondary keywords:

Bromadiolone poisoning
Bromadiolone treatment
Bromadiolone antidote
Vitamin K for bromadiolone poisoning
Bromadiolone toxicity
Bromadiolone overdose
Bromadiolone rodenticide poisoning
Superwarfarin poisoning treatment
Anticoagulant rodenticide poisoning
Vitamin K1 treatment
Bromadiolone INR
Bromadiolone coagulopathy
Rat poison poisoning treatment
Rodenticide poisoning treatment
Bromadiolone bleeding
Bromadiolone poisoning management