Lecture 5: Flea control and Pesticides

All patients with skin allergies benefit from aggressive ?control

flea

What are the 3 components of ectoparasites control?

- On the pet: kill the adult insects (parasiticides)

- On the pet: prevent progression through the lifecycle (insect growth regulators IGR)

- In the environment

All patients with skin allergies benefit from aggressive ?control

flea

What are the 3 components of ectoparasites control?

- On the pet: kill the adult insects (parasiticides)

- On the pet: prevent progression through the lifecycle (insect growth regulators IGR)

- In the environment

Relevant Questions for Product Selection?

1. is water a issue? if so give oral

2. does it kill immature flea stages?

3. will cats be exposed to the product? if so avoid most pyrethroids

4. What format will be most useful for this patient?

5. Is the patient food allergic / undergoing a food trial? (capstar has no food ingredients)

6. OK to use more than one drug simultaneously? MOA? (Drugs with the same mechanism → Avoid, or combine with caution)

Nerve impulses are produced as ? moves into the nerve cell

sodium (Na+ )

What are the 5 groups of axon parasiticides?

- Increased Na+ flux= pyrethrins/pyrethroids

- Decreased Na+ flux= metaflumizone, indoxacarb

- Increased GABA gated glutamate channels: macrocyclic lactones

- Decreased GABA and glutamate gated chloride channels= Isoxazolines

-Decreased GABA gated chloride channels= Fipronil

What are the 4 groups of synaptic parasiticides?

- Cholinesterase inhibitors= organophosphates, carbamates

- Activation of nicotinic ACh receptor-gated Ca2+ channels= spinossad, spinetoram

- Binding to nicotinic ACh receptors= Imidacloprid, nitenpyram, dinotefuran

- Monoamine oxidase inhibitors

Pyrethrins: MOA

Increased Na+ permeability along axon (—> excitation + death)

-"natural" insecticides

Pyrethrins: pros

- Safe —> good for cats and puppies

- Quick kill

Pyrethrins: cons

- UV inactivated

- Short duration of action

pyrethroids vs pyrethrins

Pyrethroids= synthetic

- longer duration of action but increased toxicity

Permethrin: MOA

Increased Na+ permeability along axon (—> excitation + death)

-In pyrethroids = synthetic pyrethrins

Permethrin: pros

- Longer duration of action

- Repels and kills fleas, ticks, and mosquitos if >2%

Permethrin: repellent?

Yes if >2%

Permethrin: safe for cats?

Only if <0.5%

Permethrin: cons

- Increased toxicity

- >0.5% toxic to cats

- Washed off by bathing

How does pyrethroid toxicity present in cats?

- tremors/muscle fasiculations

-twitches

-hyperesthesia

-seizures

-pyrexia

-ptyalism

-ataxia

-mydriasis

Permethrin: ticks?

Yes

Permethrin: examples

- Advantix 2 (44%)

- Activyl tick plus (36 %)

- Vectra 3D (42.5%)

Deltamethrin: MOA

Pyrethroid ester insecticide

Deltamethrin: pros

- Kills fleas and ticks

- Repels mosquitos and flies

- Available as a collar

- Lasts 6 months

- Water resistant

Deltamethrin: cons

- Can cause local irritaiton

- Only in dogs

Deltamethrin: cats?

No

Deltamethrin: repellent?

Mosquitos and flies, Culicoides

Deltamethrin: examples

Scalibor, activyl

Idoxacarb: MOA

axon- Blocks voltage-dependent Na+ channels (uses metabolic bioactivation in the flea to kill)

Idoxacarb: pros

- Safe for mammals

- Water resistant, topical, once a month

Idoxacarb: cats?

Yes

Idoxacarb: ticks?

No

Idoxacarb: examples

Activyl

Selamectin: MOA

Macrocyclic lactones (potentiate GABA and glutamate gated Cl- channels to interrupt axonal nerve transmission)

Selamectin: uses

- Eat mites

- Sarcoptes

- Heartworm

- Dermacentor

- In cats: + hookworms, roundworms

Selamectin: cats?

Yes- Revolution

Selamectin: pros

- Systemic absorption (doesn't work on contact), spot on

-waterproof

Selamectin: examples

Revolution for dogs + cats

-revolution plus for cats

Selamectin cons

- poor efficacy against fleas?

-does not repel

Moxidectin: MOA

Macrocyclic lactones (axon potentiate GABA and glutamate gated Cl- channels to interrupt axonal nerve transmission)

-spot on

Moxidectin: uses

Heartworm

-DOES NOT kill fleas or ticks

- (moxidectin + imidacloprid)

- ↓ efficacy of imidacloprid w/ bathing

Moxidectin: cats?

Yes

Moxidectin: examples

Advantage multi (+ imidacloprid which is not water proof)

Milbemycin: MOA

Macrocyclic lactones (axon -potentiate GABA and glutamate gated Cl- channels to interrupt axonal nerve transmission)

Milbemycin: uses

- Heartworms

- Hookworms

- Roundworms

- Whipworms

-DOES not kill ticks or fleas

Milbemycin: cats?

Yes

Milbemycin: examples

Sentinel (milbemycin + lufenuron=IGR)- once monthly tablet for dogs + cats

Ivermectin: MOA

Macrocyclic lactones (axon, potentiate GABA and glutamate gated Cl- channels to interrupt axonal nerve transmission)

Ivermectin: uses

- Heartworm

- Hookworm

- Roundworm

- Off label = demodex, sarcoptes

Ivermectin: examples

Heartgard (Ivermectin + pyrental)

- once monthly tablet

Isoxazolines MOA

-axon, inhibit GABA and glutamate chloride channels-> hyperexcitation and death of flea + tick

Isoxazolines products:

-Fluralaner= bravecto for dogs + cats

-Afoxolaner: nexGard for dogs + cats

-Esafoxolaner: NexGard combo topical for cats

-Sarolaner: simparico dogs, revolution plus cats

-Lotilaner: Credelio cats + dogs

- most once monthly and oral

-except Bravecto is 12 weeks

-all effective against ticks

-off label use demodex + other lice, maggots etc

Fipronil: MOA

Inhibits GABA gated Cl- channels-> axonal hyperexcitation

Fipronil: pros

- Concentrates in the sebaceous gland

- UV and water stable

- Safe for puppies, kittens

- Acts on fleas and ticks

- Safe in cats

- Combines adulticide (fipronil) + IGR (methoprene)

Fipronil: cons

- Doesn't repel

-bathing w/medicated shampoo appear to decrease efficacy

Fipronil: cats?

Yes

Fipronil: examples

- Frontline Plus

- Effitix (contains permethrin = dogs only)

- Frontline Tritak (dog and cat version)

Organophosphates: MOA

Synapse- Cholinesterase inhibitor

Organophosphates: cons

- No longer recommended

- Toxic to cats and young animals-> muscular twitching and seizures

Organophosphates: examples

Paramite dip for dogs

Organophosphates and Carbamates: antidote

Atropine

Carbamates: MOA

synapse- Cholinesterase inhibitor (reversible w cholinesterase)

Carbamates: cons

- Toxic

- Not recommended

Carbamates: examples

- Sevin

- Baygon

Spinosad: MOA

Synapse- Activates nicotinic ACh receptors —> hyperexcitation and death, also some effects on GABA

-non-antibiotic tetracyclic macrolide

Spinosad: considerations

- Don't give to dogs receiving high doses of ivermectin

- Lowers threshold for seizures

Spinosad: flea repellent? Ticks?

No & No

Spinosad: cats? water resistant?

Yes & yes

Spinosad: examples

- Comfortis

- Trifexis

-both oral give with food, once monthly -> starts killing fleas w/in 30 minutes

Spinoteram: MOA

Synapse- Alters nicotinic and GABA channels

Spinoteram: pros

- Once a month

- Very fast killing (<12 months)

- Doesn't interfere with other GABA binding products

Spinoteram: repellent? Ticks?

No & No

Spinoteram: examples

Cheristin for cats (Cats only)- once monthly oral

Imidaclopride: MOA

synapse- Stimulates insect nicotinic ACh receptors

-rapid knockdown

- spot-on

Imidaclopride water resistance?

poor

Imidaclopride: repellent?

Not on its own Depends on the product:

- Advantix II (+ permethrin) = yes + ticks + mosquitos, somewhat waterproof

- Advantage multi = no

- Seresto = ticks (NOT fleas)

Imidaclopride: cats?

Depends on the product:

- Advantix 2 = no

- Advantage multi = no

- Seresto = yes but reports of neuro signs + sudden death

AdvanTIX II® (imidacloprid + permethrin + pyriproxyfen):

dogs only

Repels fleas, ticks and mosquitoes

Somewhat waterproof

Seresto® collar (imidacloprid + flumethrin):

dog and cat

No need to take it off while bathing

Kills but does not repel fleas

Repels tick

Nitenpyram (capstar): MOA

synapse- Inhibits nicotinic ACh receptors

-very fast killing

-not flavored: used in animals doing food trials

Nitenpyram: pros

Example: Capstar- Kills 90% of fleas in 4 hours (dogs) and 6 hours (cats)

- 100% effective in 24 hours

- Safe in pups and kittens

- useful in clinics/ boarding facilities

Nitenpyram: cons

Example: Capstar -Only lasts 24 hours

- Doesn't repel

- No IGR

-No ticks

Dinotefuran: MOA

Synapse- Permanently binds to nicotinic ACh receptor (not mammalian)

-quick kill- adult fleas in 6 hours

Vectra 3D

- Dinotefuran: + pyroiproxy (UV-resistant IGR) + permethrin

-adult, IGR + repellent: flea, ticks, mosquitos

- Bad: decreased efficacy w bathing

-Toxic to cats

Catego

- Dinotefuran + fipronil + pyriproxyfen (UV-resistant IGR))

- fast acting

-Safe for Cats

Formanidines: i.e Amitraz MOA

synapse-Monoamine oxidase inhibitor

What species is Amitraz (Formanidines) toxic?

Cats + horses

Certifect (Amitraz)

- amitraz + fipronil + methoprene

-adulticide + IGR

-topical, monthly

-works on contact

-reported cases of pemphigus foliaceus

summary: axonal and synaptic

How to IGRs work?

inhibit development of immature stages- larvae cannot pupate

-outdoor/indoor sprays, on-animal topicals

What are the 3 insect growth regulators?

- Methoprene: sensitive to UV lights (degrades)

- Pyriproxifen: stable in UV

- Lufenuron

Methoprene: MOA

Mimics juvenile hormone (JH-1) —> prevents molting

-on animal (dog + cat) + environmental use

-Bad: UV inactivated, does not repel

Methoprene: examples

- Precor

- Frontline Plus

Pyriproxifen: MOA

Mimics juvenile hormone —> prevents molting

Pyriproxifen: pros

- Works up to 6 months

- Works on eggs and larva

- May have flea adulticide activity

- Can use in environment, indoor and outdoor

-Safe for cats

Pyriproxifen: examples

- Nylar

- Vectra 3D

- Knockout

Lufenuron (sentinel): MOA

Chitin synthesis inhibitor

-IGR

Lufenuron: Pros

- Given once a month

- Very safe for dogs and cats

- Prevents flea reproduction after a blood meal

Lufenuron: cons

- No adulticide

- Doesn't repel

-must be given with food

- Lag phase (if used alone for flea control= 3 months)

Neem oil: describe

- Botanical products

- Safe for dogs and cats

- Useful for mosquitos, fleas, ticks

- Repellent activity

Diatomaceous earth: MOA

- Absorbs lipids from insect exoskeleton —> dehydration

- Physical damage of exoskeleton

-used indoor + outdoor

Beneficial nematodes: MOA

Release toxic bacterium to kill host larva

-Steinernema and heterorhabditis

-outdoor environmental control

Sodium polyborate

-indoor environment

- dessicant

- best if professionally applied

-natural

Virbac

MOA: Synthetic pyrethroid= chemical

-outdoor and indoor versions