Pharmacology of ectoparasites Flashcards
four pathogens transmitted by fleas
- Dipylidium caninum
- acanthocheilonema reconditum
- bartonella henselae
- Rickettsia felis
what do adult fleas need to do before reproduction?
blood feed required before reproduction
- how fast do fleas feed on animal?
- how fast do they lay eggs?
- within 1 hour on animal, >85% of fleas have fed
- egg production starts 24-48 hours after first blood meal > up to 50 eggs per day/ flea
where does the adult flea live? how long does it spend on the animal?
adult flea is generally permanently on animal
seasonality of fleas in ontario
- May to november in Ontario
- Winter is too dry for them, generally
where are fleas most prevalent geographically?
mostly southeastern USA, another pocket on south-west coast of california
flea life cycle stages present in infested environment
- 5% adults
- 10% pupae
- 35% larvae
- 50% eggs
flea only products - adulticide options
- imidacloprid
- nitenpyram
Imidacloprid
- what is this drug for?
- drug class?
- action?
- licensed use?
Drug class: neonicotinoid
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Action: acts at nicotinic cholinergic synapse
> interacts with post-synaptic nicotinic receptor
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Licensed as:
- monthly spot-on for control of fleas on dogs and cats
- flea adulticide
Imidacloprid pharmacokinetics
- how it works, how fast, how long it lasts
surface translocation > whole body coverage
- distributed over entire body in 12 hours (cats) or 24 hours (dogs)
- not absorbed
- stops fleas biting 3-5 minutes after contact with drug
- kills on contact, ie. biting not required
- >99% fleas killed within 24 hours
- photostable > residual activity for 4+ weeks
imidacloprid safety / toxicity
- no reports of imidacloprid causing toxicity in dogs or cats following dermal exposure
- alcohol carrier may lead to follicular shedding (on neck)
- do not use in birds > highly toxic
imidacloprid is contained in what vet products?
- K9 Advantix II
- Advantage Multi
<><> - Advantage II + K9 Advantix II approved as pest-control products
- Advantage Multi approved as a drug
can we use imidacloprid in suckling animals?
if puppies/kittens suckling, just treat mother (minimum age for Advantage II = 7/8 weeks)
what non-flea parasites is imidacloprid labeled for?
biting/sucking lice on dogs
nitenpyram
- what is its class?
- action
- licensed use
Drug class: neonicotinoid
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Action: Action: acts at nicotinic cholinergic synapse
> interacts with post-synaptic nicotinic receptor
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Licensed as: oral adulticide for fleas on dogs & cats
nitenpyram pharmacokinetics
- rapidly absorbed into bloodstream – lasts 24 hours
- maximum blood concentration @ 0.6-1.2 hours
- 98% fleas killed in 15 minutes - 6 hours
- flea bite required for exposure
- administer daily for Flea Allergy Dermatitis
nitenpyram Toxicity/safety
very safe in dogs & cats
nitenpyram uses:
- eliminate existing flea infections
- animals on lufenuron, methoprene etc, with “hitch hiker fleas”
- prior to boarding or elective surgery
- no activity against ticks or mites
nitenpyram off-label use
myiasis
insect growth regulator drugs used for fleas
- safety
- what life stages affected
- how fast they work
- formulations
- categories
- extremely safe
- affect eggs, larvae & pupae of insects and arachnids – do not affect adults
- effective control after several weeks of treatment
- many formulated with adulticides
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Two groups:
(a) Insect Development Inhibitors
(b) Juvenile Hormone Analogs
insect growth regulator drugs used for fleas - types of drugs
(a) Insect Development Inhibitors
(b) Juvenile Hormone Analogs
- Two most frequently used:
(i) pyriproxyfen
(ii) methoprene
pyriproxyfen - what type of drug is this? use?
insect growth regulator - juvenile hormone analog
* combined with adulticide for flea control on dogs/cats:
> e.g. pyriproxyfen + imidacloprid (Advantage II)
methoprene - what type of drug is this? use and application options?
insect growth regulator - juvenile hormone analog
* spot-on - ovicide if female fleas exposed
* spray - larvicide in environment
* combined with adulticide for flea control on dogs/cats:
> e.g. methoprene + fipronil (Frontline Plus – USA)
Lack of efficacy of flea drugs ?
possible reasons
- population management ?
- infrequent owner application:
- owner concerns about toxicity
- lack of compliance
- inability to adequately apply drug
- bathing and swimming ?
- drug resistance in flea populations ??
Ticks on dogs & cats in North America - most likely in Ontario
American dog tick - dermacentor variabilis
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deer tick - ixodes scapularis
flea and tick drugs commonly used in vet med
- selamectin
- fipronil
- imidacloprid + permethrin
- imidacloprid + flumethrin
- fluralaner
- afoxolaner
- sarolaner
- lotilaner
selamectin
- what kind of drug
- calss
- pharmacokinetics
- uses
(Revolution)
Drug class: macrocyclic lactone
Pharmacokinetics:
* spot-on: slowly absorbed into bloodstream then redistributed to skin
* monthly application for dogs & cats
Uses:
* adult and larval fleas (dogs & cats)
* Rhipicephalus sanguineus on dogs (not USA)
* Dermacentor variabilis on dogs (aid in the control)
fipronil (USA)
- drug class
- action
- licensed for
- pharmacokinetics
Drug class: phenylpyrazole
Action: inhibits GABA-gated and glutamate-gated chloride channels (blocks passage of Cl- ions)
Licensed for:
- adult fleas + all stages of ticks on dogs and cats
- residual activity for 30 days
Pharmacokinetics:
* spot-on > surface translocation (sebum, sebaceous glands)
* limited dermal absorption (<1% applied dose)
fipronil safety / toxicity
- wide safety margin in dogs & cats
- note: extra-label use on young/small rabbits can result in seizures/death
fipronil is contained in:?
kills what?
residual activity?
Frontline Plus (USA)
- fipronil + methoprene
- kills adult fleas, flea eggs and larvae + ticks on dogs and cats
- residual activity for 30 days
imidacloprid + permethrin
- for what species
- kills who
Dogs
- adult fleas, all tick species
imidacloprid + flumethrin
- for what species
- kills who
dogs and cats
- adult fleas, all tick species
fluralaner
- for what species
- kills who
dogs and cats
- adult fleas, all important tick species
afoxolaner
- for what species
- kills who
dogs
* adult fleas, all important tick species
sarolaner
- for what species
- kills who
dogs
* adult fleas, all important tick species
lotilaner
- for what species
- kills who
dogs and cats
* adult fleas, all important tick species
