Pyrethrins and Pyrethroids

Question 1

T/F: Pyrethrins are synthetic versions of pyrethroids

Answer 1

false, other way around

Question 2

Compare type 1 vs type 2 pyrethroids

Answer 2

Type 1 (First generation) - do not contain an a-cyano moiety
Type 2 (second generation) do contain an a-cyano moiety

Question 3

Toxicokinetics of pyrethrins and pyrethroids

Answer 3

dermal most common, ingestion and inhalation rare. but possible
oxidized through hydrolysis and oxidation in blood + liver
conjugated metabolites excreted in urine
doesn’t accumulate in tissues

Question 4

Why are cats very sensitive to pyrethrin and pyrethroid toxicity?

Answer 4

because deficient in glucuronidase transferase

Question 5

Overall toxicity of pyrethrins and pyrethroids is:
A) cardiotoxic
B) endotoxic
C) non toxic
D) neurotoxic

Answer 5

D - neurotoxic

Question 6

T/F: fish are very sensitive to pyrethrin and pyrethroid toxicity

Answer 6

True

Question 7

Permethrin is one of the most common causes of poisoning of cats world wide?

Answer 7

Yes

Question 8

T/F: formulations of pyrethrins with piperyonyl butoxide decrease risk of moderate or major symptoms compared to pyrethrins alone

Answer 8

false, they increase them

Question 9

MoA of pyrethrins/pyrethroids

Answer 9

alter neuronal membrane permeability, Na+ and K+ transport altered
continued neurotransmitter release, repolarization of nerve inhibited, hyper-excitability of nerve

Question 10

T/F: type I pyrethroids have greater effect on sodium channels

Answer 10

False, type II (have the a-cyano group) have greater effect

Question 11

Acute clinical signs of pyrethrins and pyrethroid toxicity

Answer 11

muscle tremors, depression, blindness, ataxia, lethargy
salivation, vomiting, diarrhea, hyper excitability, drooling, lip and tongue numbness
may see seizures, dyspnea, death

Question 12

Diagnosis of pyrethrin and pyrethroid toxicity

Answer 12

Hx of exposure, CS, r/o other causes

Question 13

Treatment of pyrethrin and pyrethroid toxicity

Answer 13

no specific antidote
decontamination (no charcoal)
dont exacerbate toxicity
symptomatic tx - methocarbamol for severe muscle tremors
diazepam, barbiturates, propofol CRI for seizures

Question 14

Prognosis of pyrethrin and pyrethroid toxicity

Answer 14

With the exception of the cat, usually good

Question 15

Permethrin use in cats is typically applied at 45% without toxicity?

Answer 15

No!