Parasiticides and Insect Growth Regulators Flashcards
1
Q
What are the three parts to ectoparasite control?
A
- On the pet: kill the adult insects –> parasiticides
- essential for flea insect allergic animals
- On the pet: prevent progression thru the life cycle –> insect growth regulators
- should be incorporated into all flea control programs
- In the environment: control for adults and other life stages
2
Q
What are the targets of parasiticides?
A
- Axon –> voltage gated Na channels; GABA-glutamate or Cl channels
- Synapse –> Ca, acetylcholine, acetylcholinesterase
3
Q
What 4 groups of parasiticides target axons?
A
- Incr Na flux: pyrethrins/pyrethroids
- Decr Na flux: metaflumizone, indoxacarb
- Incr GABA gated glutamate channels: macrocyclic lactones
- Decr GABA gated Cl channels: fipronil
4
Q
What 4 groups of parasiticides target the synapses?
A
- Choliesterase inhibitors: organophophates, carbamates
- Activation of nAch receptor gated Ca channels: spinosad, spinoteram
- Binding to nicotinic acetylcholine receptor: imidacloprid, nitenpyran, dinotefuran
- Monamine oxidase inhibitors: amitraz
5
Q
Describe pyrethrins
A
-
incr Na permeability along axons
- leads to hyperexcitation and death
- derived from chrysanthemum
- good:
- safe - okay for cats and puppies
- quick flea knock down
- bad:
- UV inactivated
- short duration of action
6
Q
Describe pyrethroids
A
- Good:
- binds to hair, skin
- more photo-stable
- longer duration of action
- repels and kills fleas, ticks, mosquitoes if >2%
- Bad:
- incr toxicity
-
never apply directly to a cat!
- >0.5% = toxic to cats
- washed off by bathing
7
Q
What are examples of pyrethroid/permethrin veterinary products?
A
- Advantix II - 55% permethrin
- Actvivyl plus
- Vectra 3D - 33% permethrin,
8
Q
Describe deltamethrin
A
- pyrethroid ester insecticide
- kills flea and ticks
- repels mosquitoes, Culicoides
- available as collar
- last 6 mo
- water resistant
- can cause local irritation
9
Q
Describe indoxacarb
A
- blocks voltage dependent Na channels, interrupting the nerve impulse
- results in reduced feeding, paralysis and death of flea
- uses metabolic bioactivation in the flea to kill
- safe for mammals
- water safe, topical once a month
- canine product also has permethrin
10
Q
Describe fipronil
A
- inhibits GABA gated Cl channels –> axonal hyperexcitation
- flea adulticide
- also used in agriculture
11
Q
Describe Frontline Plus (fipronil + methoprene)
A
- Good:
- concentrates in sebaceous glands
- photo-stable
- safe for puppies and kittens
- water immersion - no change in efficacy
- combines IGR + adulticides
- activity on both fleas and ticks; safe in cats
- Bad:
- does not repel
- bathing w/ medicated shampoo appears to decr efficacy clinically
- reported decr efficacy in field
12
Q
What is Tritak?
A
- For dogs: fipronil and cyphenothrin and methoprene
- for dogs only
- For cats: fipronil, etofenprox, methoprene
13
Q
Describe Bravecto
A
- oral flea and tick control (also a topical)
- up to 12 wks of protection against fleas and ticks
- selective inhibition of arthropod GABA and l-glutamate-gated Cl channels
- for dogs > 6 mo
- effective for demodex
14
Q
Describe Nexgard (Afoxolaner)
A
- oral flea and tick control for 30d
- 100% kill within 24h
- for dogs only
- non-competitive GABA receptor antagonist, much more selective for GABA receptors in insects or ticks, than for those in mammals
15
Q
Describe Simparica (Sarolaner)
A
- oral, chewable, for dogs
- kills ticks and fleas for up to 35 d
- effective against demodex
- more effective toward the end of the month compared to Nexgard
16
Q
What parasiticides target the synapse?
A
- organophosphates
- carbamates
- spinosad
- imidacloprid
- nitenpyram
- dinotefuran
17
Q
Describe organophosphates
A
- no longer recommended!
- cholinesterase inhibitors
- used by licensed pesticide operators for mosquito and agricultural pest control
-
toxic to cats and young animals
- muscular twitching –> seizures
- antidotes: atropine and antihistamines
18
Q
Describe carbamates
A
- no longer recommended!
- less toxic, less effective
- competes irreversibly w/ cholinesterase
- toxic signs: same as OPs
- antidote: atropine
- used less frequently, environmental products only available
19
Q
Describe Spinosad
A
- Non-antibiotic tetracycline macrolide
- Activates nicotinic acetycholine receptors –> hyperexcitation –> death
- Comfortis, Trifexis
- Oral, once monthly
- Works systemically
- Should be given w/ food
- Should not be given to dogs receiving high doses of ivermectin
- Lowers threshold for seizures
20
Q
Describe Comfortis
A
- Spinosad
- approved for dogs and cats
- Good:
- chewable 1x/month tablet, no effect of bathing
- flavored with beef and pork
- starts killing fleas within 30 minutes, 100% effective within 4 hours
- flea adulticide effects last for 30d
- Bad:
- does not repel fleas
- vomiting is freq after administration
- no IGR
