The Rodenticides NO

A Toxicological Overview

Dr. Ray KentHealth Effects DivisOffice of Pesticide POffice of Pesticide PNovember 29, 2011
The RMD Rodenticid

Rodenticide TypeWarfarin Warfarin 1st generation generation anticoagulant anticoagulant

‐ cou

cou

Chlorophacinone 1st generation anticoagulant ‐ indDiphacinone 1st generation anticoagulant ‐ indBrodifacoum 2nd generation anticoagulant ‐ co

Bromadiolone 2nd generation anticoagulant ‐ co

Difenacoum 2nd generation anticoagulant ‐ co

Difethialone 2nd generation anticoagulant ‐ co

Ch l l if l Ch

olecalciferol H li ypercalcemia i dn

ducer

Bromethalin Mitochondrial uncoupler

Zinc phosphide Mitochondrial uncoupler uncoupler
Acute toxicity
Acute oral toxicity categ

Toxicity

Category Oral LD50

I U d i l di 50 /

II > 50 thru 500 m

g/k

g

Up to an

d

inc

l

udi

n

g 50

mg/

III

IV 000 /k

> 500 thru 5000 mg/kg

g g

> 5000 mg/kg
Rodenticide acute toxi

Rodenticide Type

Rat o

(m

Warfarin 1st gen anticoagulant Chlorophacinone 1st gen anticoagulant Diphacinone 1st gen anticoagulant Brodifacoum 2nd gen anticoagulant B di l romadi

olone 2 dn

d gen anti l coagu ant 

Difenacoum 2nd gen anticoagulant Difethialone 2nd gen anticoagulant anticoagulant Cholecalciferol Hypercalcemia inducer Bromethalin Mitochondrial uncoupler Zinc phosphide Mitochondrial uncoupler 
The NOIC Rodenticid
Indandione Anticoagul
Rodenticide Plasma Half

Blood

Rat

o

Rodenticide

ood

half

‐life

at o 

(m

Wfi (1

t

War

farin (1

) 40

h

s

t gen

) 40

hours

Brodifacoum (2nd Brodifacoum (2 gen) 16

‐36 days 0

Difethialone (2nd gen) no data 0Bromethalin 5.6 days 
The NOIC Anticoagula

Rodenticide TypeWarfarin Coumarin anticoagulant ‐ 1Brodifacoum Coumarin anticoagulant ‐ 2Difethialone Coumarin anticoagulant ‐ 2
The Vitamin K Cycle

Anticoagulant

Anticoagulant
Symptoms of Anticoagu

Poisoning

• El i ar y signs 

– I i l tti ti Increase in clotting tim

Not observable in a home setting, b

rather in a medical facility rather in

a medical facility. 

• Moderate symptoms - easy bruising 

bleeding from almost any tissue sucbleeding from almost any tissue suc

gums, nose, urinary tract, G.I. tract, 

• Severe symptoms Severe symptoms

- Massive loss of Massive loss of

blood leading potentially to death.
Bromethalin

• Mitochondrial uncoupler of oxida

ph h l ti hosp

horylation 

– ATP l noonge

replenished by consumption of O

• Symptoms of bromethalin poiso

occur within a few hours of in

ges

• There is no antidote similar to vi

K for bromethalin poisoning. K for bromethalin poisoning.
Symptoms of Brometh

Poisoning

• El i ar y signs 

– F t ew symp

toms are 

regarded as “signature” effects. At 

doses an individual might exhibit mdoses, an individual might exhibit m

confusion or dullness. 

• Moderate effects Moderate effects

- as cerebrospinal as cerebrospinal

pressure increases there may be indications of weakness in limb stre

• Severe effects - general paralysis o

convulsions and 

p y ossibl

y death
Conclusions

• All of the rodenticides are high

toxic if ingested

• A single bite of any of the A single bite of any of the

rodenticides by a child poses 

unaccept bl i k t

able ris

k

s

• Prevention of ex

posure is the 

surest way to avoid risks from rodenticide ingestion rodenticide ingestion