Antiparasitics Flashcards
Selamectin
Revolution (Zoetis) /Paradyne (VCA)
Macrocyclic lactone
Binds to glutamate-gated chloride channels and hyperpolarizes neuromuscular junctions of insects and helminthes
Flea (Aduliticide, larvicide, ovicide), anthelmintic, tick (R.sanguineus, D. variabilis), hw (no microfilariae), ear mites, roundworm, hookworms
In dogs-American dog tick and Scabies (q 2wks, 3 x)
Fipronil
Frontline (Merial)
GABA chloride channel antagonist
Fleas, ticks, mites-otodectes
Fipronil +methoprene (not UV light stable)
Frontline Plus (Merial)
Fipronil -GABA chlorid channel antagonist
Methoprene kills ova and larvae, insect growth regulator
Frontline Plus-tickes, mites (otodectes), fleas, mosquitoes
Imidaclopromid
Advantage (Bayer)
Imidaclopromid-Irreversibly bind at nicotinic Ach receptor sites on the parasite
Fleas only
Imidaclopromid+pyriproxyfen
Advantage II (flea only) (Bayer)
Imidaclopromid-Irreversibly bind at nicotinic Ach receptor sites on the parasite
pyriproxyfen-insect growth regulator/juvenile hormone analog that prevents larvae from development into adults
Fleas only
Imidaclopromid + permethrin
Advantix (Bayer)
Imidaclopromid-Irreversibly bind at nicotinic Ach receptor sites on the parasite
permethrin - keeps sodium channel open
Do not use in cats!
Fleas (adulticide), ticks (R. sanguineus, D. variablis, A. americanum, Ixodes), mosquitos, flies, lice (tunga penetrans)
Imidaclopromid + moxidectin
Advantage Multi (Bayer)
Imidaclopromid-Irreversibly bind at nicotinic Ach receptor sites on the parasite
Moxdectin-gluatmate gated chloride ion channel
Fleas(adulticide, larvicide), heartworm, roundworms, hookworms, whipworms, lice (trichodectes), mites (otodectes cynotis, demodex canis, sarcoptes)
Nitenpyram
Capstar (Novartis)
Acitivates insect specific nicotinic acetylcholine receptors
Age: for dogs and cats>4 weeks old
Dose by size; freq: 24 hours, can be used with lufenuron for sustained effect
Flea adulticide only
Dinotefuran/Pyriproxifen
Vectra / Simpleguard -no perimtherin
Dinotefuran-mimics Ach
Pyriproxifen-insect growth regulator
-mimics insect juvenile growth hormone, halting development during metarmorphosis and larvae development. Also concentrates on female flea ovaries, causing non-viable eggs to be produced.
Fleas only
Dinotefuran + Pyriproxifen + Permethrin
Vectra 3D
Dinotefuran-mimics Ach
Pyriproxifen-insect growth regulator
-mimics insect juvenile growth hormone, halting development during metarmorphosis and larvae development. Also concentrates on female flea ovaries, causing non-viable eggs to be produced.
Permethrin-keeps sodium channel open
Vectra 3 D- Repels and kills fleas, ticks, mosquitoes, biting and sand flies, lice and mites (excluding mange mites)
Fleas-eggs, larvae, pupae, adults
Spinosad
Comfortis (Elanco) / Acuguard (VCA)
Dinotefuran-mimics Ach
Pyriproxifen-insect growth hormone mimic to prevent molting
Nonbacterial tetracyclic macrolide; activates nicontic Ach receptors on parasite (involuntary muscle contracts)
DO NOT USE WITH IVERMECTIN (may cause ivermectin toxicity)
Do not use in seizure patients
Flea adulticide
Spinosad + milbemycin
Trifexis (Elanco) / Comobguard (VCA)
Spinosad- Nonbacterial tetracyclic macrolide; activates nicontic Ach receptors on parasite (involuntary muscle contracts
Milbemycin -macrolide related to avermectin; open glutamate sensitive chloride channels
DO NOT USE WITH IVERMECTIN (may cause ivermectin toxicity)
Do not use in seizure patients
fleas, adult hookworm, roundworm & whipworm
Amitraz
Mitaban (Upjohn)
Inhibits monoamine oxidase in mites (demodex)
Causes sedation in dogs (α2 agonist); PUPD< bradycardia, hypothermia, hyperglycemia, seizures
Do not use pets / people taking other MAOI, selegiline or diabetic people.
Age for dogs and pups> 8 weeks, freq 42 days for flea, 30 days for ticks
Demodex mites
Comes in dip (mitaban) and collar (Preventic)
Amitraz
Preventic (Virbac)
Causes sedation in dogs (α2 agonist); PUPD< bradycardia, hypothermia, hyperglycemia, seizure. Do not use pets / people taking other MAOI, selegiline or diabetic people.
Kills tick and demodex mitess
Collar
amitraz +metaflumizone
Promeris (Pfizer) - discontinued
Promeris Duo, Promeris for dogs
Amitraz -Inhibits monoamine oxidase in mites
metaflumizone -just kills fleas by disrupting flea neural axonal impulses-binds sodium channels causing insect paralysis
Topical flea preventative
Promeris-Fleas (adulticide), tickes, Ixodes, dermacenter, A. americanum, R. sanguineus, mites (Demodex canis)
metaflumizone
Promeris (Pfizer) - discontinued
metaflumizone -just kills fleas by disrupting flea neural axonal impulses-binds sodium channels causing insect paralysis
Fleas only
Lufenuron/milbemycin oxime
Sentinal (Novartis) -HW +Fleas
Lufenuron
Program (Novartis) - kills developing fleas only
Milbemycin oxime
Interceptor (Novartis)- fleas only
Lufenuron-inhibits the production of chitin in larval fleas
Milbemycin-opens glutamate gated chloride channels in neurons of invertebrates causing hyperpolarization
Fleas (larvcide, ovicde), nematodes (d. immitis, ancylostoma, toxocara, trichuris vulpis)
No longer available
Dinotefuran
3rd generation neonicotinoid class insecticide
Binds to nicotinic receptors in the nerve synapse, causing continuous nerve stimulation and death of insect
Vectra- has pyriproxyfen too
Vectra 3d- dogs only bc has permethrin
Fipronil
An insecticide and acaricide in the phenylprazole class.
Acts as an antagonist at the gamma- aminobutyric acid (GABA)
receptor
Frontline spray or spot on
Use for non-follicular mite and lice
Ticks in dogs
Toxic to rabbits
Formamidines
Acaricidal agents act by inhibition of monoamine oxidase. They are also prostaglandin synthesis inhibitors and alpha-adrenergic agonists.
Amitraz available as rinse, spot-on, and collar.
Good to kill demodex, feline demodex, chyeletiella, otodectes, sarcoptic, and notedres
Examples: Mitaban rinse( zoetis), certificate spot application (merial), preventic (vibrac)-doesn’t help demodex
Unstable and oxidizes rapidly when exposed to air and sunlight therefore, do not use expired product.
Side effects of Amitraz: transient sedation, pruritus, hypothermia, bradycardia, hypotension, hyperglycemia (be careful in DM patients)
Insect growth regulators
Two types
1) juvenile growth hormone analogs
Prevents maturation of pupae to larvae
Ex. Methorprene, fenoxycarb, pyriproxyfen
Adult fleas exposed continuously to pyriproxyfen die of internal organ damage after 5-10 days of exposure. During feeding the flea is exposed to the agent and the eggs fall off. These eggs do not hatch.
2) chitin synthesis inhibitors
Imidacloprid
Chloronicotinyl nitroguanidine class.
It binds to the flea’s nicotinic receptor on the post synaptic neuron and blocks impulse transmission.
Kills fleas and lice
Advantage II has pyriproxyfen
Advantix II has permethrin and kills ticks, biting flies, and Mosquitos too
Advantage multi has moxidectin which kills heart worm, various GI worms, fleas and live. The European product which has the identical formulation is also labeled to kill lungworms, ear mites, scabies and demodicosis
Metaflumizone
Semicarbazone
Blocks sodium channels in insects resulting in nerve paralysis.
Promeris (Fort Dodge)
Associated with drug triggered pemphigus foliaceus and has been withdrawn from market
Pyrethrin
Volatile oil extract of the chrysanthemum flower
Can be rapidly inactivated by UV light.
Bc of low toxicity, rapid inactivation, and lack of tissue residue and buildup so relatively environmentally safe but still toxic to fish and bees.
Cats may develop cns tox in piperonyl butoxide.
Pyrethrin is effective against fleas, otodectes, flies, lice, and mosquitoes
Sulfur
Lime sulfur dip (lime plus dip by Dechra)
Very safe. Inexpensive.
Txt for nonfollicular mites (sarcoptes, notoedres, chyeletiella, chiggers, fur mites and lice), fungicidal, bactericidal, keratolytic, antipruritic.
Drawbacks: fowl odor, stains jewlery, temporarily discolors hairs (white)
Macrolytic lactones
Avermectin ( ivermectin, doramectin, abamectin, selamectin)
Milbemycins (milbemycin, moxidectin)
MOA: potentiating the release and effects of GABA. Avermectins are also agonists of glutamate-gated chloride channels.
Pgp is encoded by MDR-1 or ABCB1. Pgp limits penetration of substances into CNS.
Nt230 (del4) mutation is well known in various herding breeds. Homozygous dogs are susceptible to intoxication, heterozygous are intermediate sensitivity.
Recommend challenge test. 0.05mg/kg po SID, 0.1, 0.15, 0.3, 0.3mg/kg and watch for CNS signs.
The issues is whether therapeutic dosage to treat external parasites is above or below intoxicating dosage
Ivermectin
Kills nematodes, microfilaria, sarcoptes, chyeletiella, demodex, notoedres, and otodectes. Ivermectin does not affect trematodes and Cestoda bc GABA is not involved in neurotransmission in those species. Parasite paralysis is main action but also suppresses reproduction. Ticks are not killed but their egg production and molting is suppressed.
Milbemycin
Milemycin is like ivermectin but also kills some intestinal parasites.
Used to treat nasal mites, scabies, and generalized demodecosis.
Products with milbemycin:
Interceptor
Trifexis
Moxidectin
In USA, only labeled for dogs and cats but in Europe, ferrets too.
In the USA only labeled for fleas but elsewhere, labeled for fleas, lice, ear mite infestation, sarcoptic mange, and demodecosis. Licensed for once every 4 weeks, but need more frequent application if treating other things, especially demodex.
Products with moxidectin:
Advantage multi
Also licensed in cattle to treat: various nematodes, hypoderma sp., mites, lice, and horn flies.
Selamectin
Selamectin is a semisynthetic avermectin. It is identified in sebaceous glands, hair follicles, and basal layers of the epithelium. Ok to use in ivermectin sensitive dogs at manufacturer’s recommendation.
Prevents heartworm disease, kills adult fleas and prevents their eggs from hatching, and treats and controls ear mites in cats and dogs. Also treats and controls canine scabies and Dermacentor variablis infestation in dogs.
Revolution
Insect development inhibitors
Fleas feeding on treated blood lay eggs that do not hatch or develop beyond the larval stage. Larvae feeding on the feces of treated fleas do not develop.
Product:
Lufenuron (program, sentinel)
-it is a benzoyl phenol urea compound that inhibits chitin synthesis
Neonicotinoid
MoA: act at the nicotinic acetylcholine receptor
Nitenpyram( capstar) is a flea adulticide. It exerts it’s action at the postsynaptic nicotinic acetylcholine receptor of the insect. Unlike imidacloprid, which is a paralytic, nitenpyram produces hyperexcitability. It is rapidly absorbed and kills 100%in 3-4 hours but no activity after 48 hours.
Spinosad
Moa: activity occurs at the nicotinic acetylcholine receptor but does not interact with known insecticidal binding sites of other nicotinic or GABA-ergoc insecticides. It produces hyperexcitability, paralysis, and death of the insect.
Adverse neurological side effects may occurs when co-administered with high dose ivermectin. Data suggest Spinosad acts as a Pgp inhibitor, with resultant increased blood and CSF levels of ivermectin.
