Bromethalin Rodenticide

Question 1

Is bromethalin a general use or restricted use pesticide?

Answer 1

general use

Question 2

What species is more sensitive to Bromethalin poisoning?

Answer 2

Cats are more sensitive than dogs

Dogs are more susceptible as they are more likely to ingest it

Question 3

What species are resistant to Bromethalin poisoning?

Answer 3

Guinea pigs

they lack the correct metabolic enzymes for lethal synthesis

Question 4

Is bromethalin lipophilic or water soluble?

Answer 4

Lipophilic - readily absorbed orally

Question 5

Where is Bromethalin distributed in the highest amount in the body?

Answer 5

Fat and brain

Question 6

What is the metabolism of Bromethalin ?

Answer 6

metabolized by N-demethylation in the liver to a MORE TOXIC metabolite: Desmethylbromethalin

***lethal synthesis

Question 7

What is the half life of Bromethalin and how is it excreted?

Answer 7

Half life in the rat = 5-6 days

mainly excreted in the bile, small amount in the urine

*likely undergoes enterohepatic recirculation

Question 8

What is the MOA of Bromethalin ?

Answer 8

Uncoupleing of oxidative phosphorylation

= lack of adequate ATE and insufficient energy for Na/K ion pumps

Question 9

What are the primary targets or tissues affected by Bromethalin toxicosis?

Answer 9

Brain and Spinal cord

• these rely heavily on oxidative phosphorylation
• further tissue damage may occur through lipid peroxidation

Question 10

T/F: Signs for Bromethalin toxicosis are always acute

Answer 10

FALSE

acute or delayed
*acute is less common

Question 11

What clinical signs are associated with acute Bromethalin toxicosis?

Answer 11

occurs 2-36hrs post ingestion

“convulsant syndrome” - generally a higher dose

CNS excitatory signs - severe muscle tremors, hyperthermia, running fits and hyper excitability - that may be precipitated by light or noise

(may note CNS depression in end stage)

Question 12

What is the prognosis of Bromethalin Convulsive syndrome?

Answer 12

POOR

difficult to treat

Question 13

What are the clinical signs associated with subacute Bromethalin toxicosis?

Answer 13

onset 1-4 days - MORE COMMON - Paralytic syndrome

Develops within the first few days and progresses over 1-2 weeks

hind limb ataxia, proprioceptive deficits, paresis, can progress to paralysis and loss of deep pain

CNS depression
Other: vomiting, anorexia, nystagmus – may progress to sz late stage

Death may occur due to respiratory failure

Question 14

What lesions are associated with Bromethalin toxicosis?

Answer 14

Cerebral edema (intramyelinic edema)
Diffuse white matter vacuolization in the white matter

Question 15

Paralytic syndrome is usually associated with what kind of Bromethalin dose?

Answer 15

Lower dose

Convulsive syndrome = high doses

Question 16

What are the most important factors for diagnosing Bromethalin toxicosis?

Answer 16

History and clinical signs

theres nothing very striking in blood work besides a mild hyperglycemia

Chemical analysis is expensive and takes a long time

Question 17

What is essential to prevent further CNS damage due to Bromethalin ?

Answer 17

Decontamination!!

Emetic is only successful if it is done within 1-2hours post ingestion since it is quickly absorbed

• Activated charcoal with sorbitol - needs to be repeated
• want to avoid cathartics with magnesium

Question 18

What is sorbitol?

Answer 18

A cathartic - will act as an osmotic agent to pull fluid into the colon

Should do one dose of toxiban with sorbitol and repeat doses without sorbitol to prevent hypernatremia

Question 19

What is the treatment for Bromethalin toxicosis?

Answer 19

lipid emulsion therapy should be considered

Supportive and symptomatic when signs are present - mannitol, furosemide, anticonvulsants, Gingko biloba

Question 20

What is the prognosis of Bromethalin toxicosis?

Answer 20

Mild cases - signs may resolve over several weeks

Severe cases = grave