Pyrethrins and Pyrethroids Flashcards
Where is pyrethrin extracted from?
pyrethrum flowers
Pyrethrin uses
flea and tick control in dogs and cats
Dairy and Farm insecticide
Home insecticide
Pyrethrin Properties
Esters
very unstable in air and light
What are the 2 types of Pyrethroids?
Type 1 Pyrethroids - do not contain alpha-cyano moiety
Type 2 Pyrethroids - contain alpha-cyano moiety
Pyrethrin toxicokinetics
Lipid soluble
NO Accumulation in the tissues!!
Pyrethrin exposure
Oral
Dermal
inhalation
What is often added to Pyrethrins?
Piperonyl butoxide
Pyrethrin toxicity
Low toxicity to mammals
Very toxic to fish and some birds
What decreases the rate of hydrolysis of Pyrethrins?
The presence of Alpha-cyano moiety
Piperonyl butoxide
added as a synergist to inhibit Pyrethrin metabolism by insects
Pyrethrin mechanism of action
delay closure of sodium ion channels in the axonal membrane of the insect
May inhibit ATPase leading to repetitive firing
bind more strongly at lower temperatues
What is the “knockdown effect”?
rapid paralysis caused by inhibition of neurons - immobile but NOT DEAD!!
What Type 2 Pyrethroids interfere with?
GABA
Glutamic acid
Clinical signs of Pyrethrin toxicosis?
Salivation vomiting diarrhea hyperexcitability Generalized muscle tremors seizures dyspnea prostration death reversible blindness acute paralysis
What are the lesions associated with Pyrethrin toxicosis?
No specific lesions
