pharmacology of ectoparasites - ticks and mites Flashcards
what is pyrethrin? effect on parasites?
- natural derivative of Chrysanthemum plant:
> rapid paralysis & death of ticks, fleas, flies, lice
> rapid degradation in sunlight
synthetic pyrethroids
- properties of third and fourth gen products, common products used
Third generation - noted for photostability + potency:
* permethrin = most commonly formulated pyrethroid
- approved for dogs (adult ticks, fleas)
- commonly used on food animals
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Fourth generation – most potent + most persistent:
* flumethrin – collar for dogs & cats in USA (adult ticks, fleas)
permethrin
- what is this drug, what is it approved for? use?
synthetic pyrethroid
= most commonly formulated pyrethroid
- approved for dogs (adult ticks, fleas)
- commonly used on food animals
flumethrin use
synthetic pyrethroid
– collar for dogs & cats in USA (adult ticks, fleas)
synthetic pyrethroids mechanism of action, pharmacokinetics? toxicity?
- cause voltage-gated sodium channels to remain open:
> membrane depolarization > rapid paralysis
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Pharmacokinetics: - dermal absorption = very limited:
- tendency to remain in outer layer of skin as lipophilic
- many have minimal meat or milk withdrawal times following topical administration to food animals
- generally rapidly detoxified in liver:
- note: cats deficient in hepatic glucuronyl transferase
permethrin should not be used for what animal?
cats, aquatics
permethrin is contained in what products? what does this product do?
- K9 Advantix II (permethrin + imidacloprid + pyriproxyfen)
- kills adult fleas and all ticks on dogs
- residual activity for 30 days
- recently introduced to OTC market
<><> - other OTC products, eg. Hartz
- kills adult fleas and all ticks on dogs
- residual activity for up to 30 days?
permethrin safety / toxicity? signs of toxicity?
- dermal exposure rarely > significant systemic absorption
- grooming by cats can > significant oral ingestion
- clinical toxicity most common in cats:
> dog formulation applied topically to cat
> (physical contact with treated dog)
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clinical signs of toxicity - tremors, seizures, hyperexcitability, salivation, weakness
- onset = minute-hours
- if supportive therapy, may resolve in 24-72 hours:
> wash in luke-warm water + dish soap
> methocarbamol +/- diazepam
<><> - highly toxic for aquatic animals
flumethrin
- type of drug
- contained in what products
- action, species
synthetic pyrethroids
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contained in:
- flumethrin + imidacloprid (Seresto) – USA only
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Action:
* collar for dogs + cats
* controlled release to skin, non systemic
* kills all tick species and adult fleas
* residual activity for 8 months
types of isoxazonlines used in vet med
- fluralaner
- afoxolaner
- sarolaner
- lotilaner
isoxazolines (eg. fluralener) mechanism of action
inhibitor of GABA- and glutamate-gated chloride channels
fluralaner ingestibles - licenced use, products
Licensed for adult fleas + ticks on dogs:
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(i) Original “chewable” oral product (PO):
* treatment & control of fleas + D. variabilis for 12 weeks
* aid in treatment & control of I. scapularis for 8-12 weeks
(USA: treatment & control of I. scapularis for 12 weeks)
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(ii) Bravecto One (PO):
* treatment & control of fleas, D. variabilis & I. scapularis for one month
fluralaner pharmacokinetics
- admin, how it kills, young animals?
- oral, systemic
- administer with food
- fleas and ticks must feed to be exposed
- 3 month product not approved for puppies <6 months
fluralaner safety / toxicity
- mild, transient, gastrointestinal effects (e.g. vomiting, anorexia, diarrhea), neurological?
Topical fluralaner for dogs
- licensed for?
- adult fleas and ticks:
> treatment and control of fleas for 12 weeks
> aid in treatment and control of I. scapularis and D. variabilis for 12 weeks
