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Flashcards in Ectoparasiticides Deck (67):
1

What are the species that Ectoparasiticides target?

Blood feeding (including culicidae, tabanis...) and non-biting (gastrophilus bots, oestrus ovis and cuterebra spp. seen in puppies and kittens)
-Lice
-Fleas

2

Lice morphology:

Highly host specific.
-Speices infecting dogs, cats, horses, poultry, pigs and ruminants.
-Entire lifecycle is on the host, live on the host all year.

3

What are the two varieties of lice?

Chewing lice (mallophaga) Bovicola bovis.
Sucking lice (anoplura) Haematopinus eurysternus
*Seen on skin scrape.
*Both spend their entire life cycle on the host.

4

Fleas morphology

Ctenocepalides felis infects dogs AND cats.
Blood sucking parasites.
Only leave host to lay eggs.
Adults live for 2+ years.
Pupa: stable in the environment for up to a year, hatch in response to vibration.
Vectors: D. caninum (zoonotic tapeworm), D. reconditum and bartonella henselae.

5

Tick morphology

Hard ticks (ixodidae) and soft ticks (argasidae)
Disease is caused by..
Exsanguination/anemia, infection secondary to bite wounds, pruritus, paralysis, toxicosis, and disease transmission.

6

Mites morphology:

Burrowing (demodex, sarcoptes scabei) and non burrowing (otodectes and cheyletiella)

7

*******A "good" ectoparasiticide should..

1. Be an effective adulticide AND repellant.
2. Persist at an effective dose on the skin for an extended period of time (promotes compliance, 1 to 3 months is the rule of thumb)
3. Be stable in sunlight, shampoo and water.
4. Cause minimal contamination of the environment (reduces risk of resistance development).

8

********What are the routes of absorption for topical agents?

Trans-epidermal and trans-follicular.
*Also Lateral diffusion.

*Gets absorbed in the systemic circulation and gets redistributed in the cutatneous blood supply all over the body. Not just on the skin.

9

Describe trans-epidermal absorption for topical agents

Intracellular diffusion.
Transcelluar, confined to the interstitial space.
Epidermal thickness: pigs> cattle> dogs > cats.

10

Describe trans-follicular absorption for topical agents

It is BOTH trans-epidermal and sweat pore.
Sweat pore is due to accumulation in sebaceous glands. Variation in this route due to hair structure in different species.

11

General aspect of a topical ectoparasiticide?
Commercial products combine multiple agents..

Liquid formulations contain spreading agents (oils and alcohols) *that can lead to toxicity*
PVC slows release of agents in collars and ear tags. It is important to remove ear-tags before slaughter.

12

General aspect of a topical ectoparasiticide?
Individual agents are large molecular weight..

-Slow dermal absorption
-Low systemic bioavailability (increased by ingestion following licking, long tissue and plasma half lives, large volumes of distribution).

13

General aspect of a topical ectoparasiticide advantages?

Avoids the GI tract.
Avoids first pass metabolism in the liver.

14

General aspect of a topical ectoparasiticide disadvantages?

Risk of overdose (client non-compliance, overuse) and licking behavior.
Prolonged withdrawal times in food animals.

15

*******Fipronil
(Frontline Plus)
*Ectoparasiticide
Indications for use?

Fleas, ticks, biting lie, ear parasites and t. autumalis.

16

********Fipronil
(Frontline Plus)
*Ectoparasiticide
Pharmacodynamics:

Noncompetitive inhibitor of glutamate-activated chloride channels (GluCl)
-Present in nematodes, insects and arthropods but NOT mammals. Causes rigid paralysis and CNS disruption.

Like GABA channels in insects. Are inhibitors of stimulation, cause hyperpolarization, paralysis and CNS disruption in the flea.

17

Fipronil
(Frontline Plus)
*Ectoparasiticide
P.Kinetics:

Applied monthly for most applications, but sprays and eardrops are used as needed.

18

Fipronil
(Frontline Plus)
*Ectoparasiticide
Adverse effects?

No reports of adverse effects in dogs or cats at the 5x maximum dose.

19

Neonicotinamides:
Imidacloprid (advantage) and Nitenpyram (capstar)
*Ectoparasiticide
Indications for use:

Fleas
-useful for fleas that are resistant to fipronil.
-imidacloprid (advantage) adult fleas and larvae; kills in 1 hour
-nitenpyram (capstar) adults only; kills within 30 minutes *fastest anti-flea drug*

20

*******What is the fastest anti-flea drug?*******

Nitenpyram (capstar)
*Even exposure to flea material can induce puritis in a dog and cat, it doesn't have to have fleas. Good first treatment!**
******Kills within 30 minutes*****

21

*******Neonicotinamides:
Imidacloprid (advantage) and Nitenpyram (capstar)
*Ectoparasiticide
P.Dynamics:

Agonist of the insect postsynaptic, nicotinic AChR.
Does not strongly react with the mammalian nAChR.

22

Neonicotinamides:
Imidacloprid (advantage) and Nitenpyram (capstar)
*Ectoparasiticide
P.Kinetics (Nitenpyram)

Administered PO (100% BA)
3 hours dogs and 8 hours cats.

23

*********Neonicotinamides:
Imidacloprid (advantage) and Nitenpyram (capstar)
*Ectoparasiticide
Adverse effects?

Imidacloprid (advantage): nicotinic and hepatic effects if ingested.
nitenpyram (capstar): no effects when administered to dogs or cats at 4x the recommended dose.
Relatively safe

24

Pyrethrins/Pyrethroids
*Ectoparasiticide
Indications for use:

Fleas and ticks
3rd generation chemicals also have some mite and lice coverage.
1st, 2nd, 3rd and 4th generations.

25

Pyrethrins/Pyrethroids
*Ectoparasiticide
1st generation:

*****Allethrin and etofenprox (lowest stability and potency)
*safest drug choice for cats

*Know the two first generations, every other drug besides these two is toxic in the cat*

26

Pyrethrins/Pyrethroids
*Ectoparasiticide
2nd generation

Phenothrin (hartz ultraguard) and Resmethrin (foggers in the barn)

27

Pyrethrins/Pyrethroids
*Ectoparasiticide
3rd generation

Permethrin (advantix)
Fenvalerate (ear tags)

28

Pyrethrins/Pyrethroids
*Ectoparasiticide
4th generation

Cyfluthrin, cypermethrin..
Used in ear tags.
Highest stability and potency.

29

************Pyrethrins/Pyrethroids
*Ectoparasiticide
P.Dynamics:

Activates sodium channels in the nerves. Causes *****repetitive depolarization's leading to parasite death. 100-1000x more selective for parasite vs mammalian sodium channels! (lower in cats-danger)***********
*Nerve stimulation.

30

*****Pyrethrins/Pyrethroids
*Ectoparasiticide
Toxicity:

2nd generation and greater are ASOLUTELY toxic to cats!!!
Ingestion by grooming.
Metabolism requires glucuroniation.
***Signs similar to organophosphate toxicity!*********
-SLUDGE; salivation, lacrimation, urination, defecation, GI distress nd emesis.
-Also miosis, tremors/convulsions and dyspnea.
-all signs occur at toxic levels in ALL animals


DO NOT GIVE WITH synergists:
-Piperonyl butoxide
-N-octyl bicycloheptene dicarboximide.

31

******Pyrethrins/Pyrethroids (*Ectoparasiticide) especially this generation is toxic to cats..

2nd generation and greater are ASOLUTELY toxic to cats.

32

*******Synergists:
-Piperonyl butoxide
-N-octyl bicycloheptene dicarboximide.
*Ectoparasiticide
P.Dynamics:

Block cytochrome P450 in insects.
Inhibits oxidative and hydrolytic metabolism.
Prevents enzymatic breakdown of pyrethrins (prevents the breakdown of drugs)
*Seen in advantix
***Extends circulating lifetime of the agents,
When you give Pyrethrins/Pyrethroids it is MORE TOXIC

33

Synergists:
-Piperonyl butoxide
-N-octyl bicycloheptene dicarboximide.
*Ectoparasiticide
Adverse effects:

None associated with MCK 264.
Piperonyl butoxide prevents breakdown of pyrethrins in cats and increases the toxicity.
*Seen in advantix

34

What are organophosphates?

*Ectoparasiticide
Available as OTC generics.
Spray-ons/Dusts: fenthion and famphur.
Ear tags: diazinone and pirimiphos
Collars: tetrachlorvinphos (seen in Hartz ultra guard flea and tick collar) diazinone and dichlorvos

35

What are carbamates?

*Ectoparasiticide
Shampoos and dusts: Carbaryl
Collars: propxur.

36

********What are the pharmacodynamics of organophosphates and carbamates?
*Ectoparasiticide

Acetylcholinesterase inhibition.
Blocks the break down of ACH in the neuromuscular junction.
DOC to reverse? 2-PAM/Pralidoxime

37

*******Organophosphates and carbamates
*Ectoparasiticide
Toxicity?

Signs: SLUDGE
Tx: 2-PAM/Pralidoxime
Sensitive breeds: cattle (brahman, charolais and Simmental) dogs (greyhounds and whippets) and cats.
-Beware of developing resistance.
-Environmental persistence.
-Highly variable withdrawal times (0-45 days depending on the product)

38

What is the reversal/tx of organophosphates and carbamates toxicity?
*Ectoparasiticide

Tx: 2-PAM/Pralidoxime

39

**********Amitraz
*Ectoparasiticide
Indications:

-Generalized Demodex in dogs and demodicosis in cats (mitaban)
-Fleas and ticks on dogs (spot-treatment and collar)
-Ticks, mites, lice on swine and cattle Taktic** CAN KILL HORSES AND DOGS.

40

Amitraz
*Ectoparasiticide
Tactic warning

-Ticks, mites, lice on swine and cattle Taktic** CAN KILL HORSES AND DOGS.

41

****************Amitraz
*Ectoparasiticide
P.Dynamics:

MAO inhibitor that acts preferentially in mites over mammals.
Causes toxic catecholamine levels in mites.

42

Amitraz is similar to what other drug?
*Ectoparasiticide

Xylazine (reduces Norepi)

43

*******Amitraz
*Ectoparasiticide
Adverse effects related to a2-adrenergic agonists in mammals:

-Mechanism of adverse effects is DIFFERENT than that for parasite toxicity.
-Sedation is the most common
-Bradycardia
-May also cause vomiting, diarrhea and ataxia.

44

Amitraz (*Ectoparasiticide) by what administration causes the most common toxicity?

PO administration the most dangerous for Amitraz.
Swallowing dip or impregnated collar.
-Endoscopic removal of collars is needed.

45

Amitraz (*Ectoparasiticide) is particularly dangerous in what speices?

Toy breeds, dogs under 4 months, cats, and rabbits.

46

*******Amitraz (*Ectoparasiticide) DOC for reversal?

Atimaezole (like Xylazine) - alpha 2 agonist in mammals*****

47

*******Metaflumazone (*Ectoparasiticide)
P. Dynamics

Has Amitraz in dog Promeris, sole ingredient in cat Promeris.
Blocks the axonal sodium channels in insects by bidning the inactivated state.
*Mechanism similar to LIDOCANE**

48

*******Metaflumazone (*Ectoparasiticide) has similar pharmacodynamics to

LIDOCAINE (for insects)

49

Metaflumazone
(*Ectoparasiticide)
P. Kinetics

Not absorbed systemically
Residual storage depot is in the hair follicles.
Spreads through the skin to different hair follicles.

50

Metaflumazone
(*Ectoparasiticide)
Adverse effects:

Pemphigus foliaceus- like pemphigoid dermatitis in dogs localized to the dorsal trunk, ears and face.
*Looks like multifocal areas of ulcerative hair loss.

51

Insect GROWTH regulators:
(*Ectoparasiticide)
Also called Juvenile Hormone regulators
Indication for use?

Fleas in dogs and cats.
-methoprene in frontline plus
-pyriproxifen in advantage II

52

*****Insect GROWTH regulators:
(*Ectoparasiticide)
Also called Juvenile Hormone regulators
P.Dynamics?

*****-Hormones that induce flea maturation when the decrease; maintaining HIGH levels of drug prevents insect maturation!!
-Pyriproxyfen also concentrates in flea ovaries and creates non-viable eggs
-Pyriproxyfen is more stable to UV light then methoprene.******* (better pyriproxyfen)

53

Insect GROWTH regulators:
(*Ectoparasiticide)
Also called Juvenile Hormone regulators
Adverse effects:

Very safe alone, but are included in combination products that have permethroids, so be sure to only use cat products in CATS.

54

Insect DEVELOPMENT inhibitors:
*Iufeneron, program and sentinel
(*Ectoparasiticide)
Indications for use:

Fleas in dogs and cats

55

*********Insect DEVELOPMENT inhibitors:
*Iufeneron, program and sentinel
(*Ectoparasiticide)
P. Dyamics:

Drug is consumed by fleas in blood meal and is excreted by not absorbed.
Flea larvae feeding on adult flea feces ingests the drug.
Larval fleas drugs inhibits production of chitin exoskeleton during pupal stage of development.
*Has to go through two organisms.

56

Insect DEVELOPMENT inhibitors:
*Iufeneron, program and sentinel
(*Ectoparasiticide)
P. Kinetics

Administered PO (dogs, 40% BA) and SC in cats.
Initially accumulates in adipose tissue then is redistributed to the plasma.

57

Insect DEVELOPMENT inhibitors:
*Iufeneron, program and sentinel
(*Ectoparasiticide):
Adverse effects:

Injection site reactions (very severe in dogs).

58

Insect repellents:
(*Ectoparasiticide)
Examples:

Butoxypolypropylene
Dinpropyl isocinchomeronate (MGK 326)
Diethyl-m-toluamide (DEET)

59

Insect repellents:
(*Ectoparasiticide):
Effects;

Reduce insects landing on/entering the hair-coat of animals.
Interferes with ectoparasite feeding.
Ectoparasite disorientation.

60

*********Insect repellents:
(*Ectoparasiticide)
DEET: Diethyl-m-toluamide
Adverse effect?

DEET may increase dermal absorption and increase adverse effects of primary ectoparasicides in cats.

61

What are the insect growth regulators?
*Ectoparasiticides

Juvenile Hormone analogs (methoprene and pyriproxyfen) and Insect development inhibitors (iufenuron)

62

What are the organophosphate/carbamate drugs?
*Ectoparasiticides

Fenthion
Famphur
Tetrachlorvinphos

63

What are synergists?
*Ectoparasiticides

Piperonyl butoxide
N-ocytl-bicycloheptene dicarboximide.

64

What are the pyrethroids?
*Ectoparasiticides

Allethrin (1st generation)
Etofenprox (1st)
Phenothrin (2nd)
Resmethrin (2nd)
Permethirn (3rd)
Fenvalerate (3rd)
Cyfluthren (4th)
Cypermethrin (4th)

65

What are the neonictinamide drugs?*Ectoparasiticides

Imidacloprid
Nitenpyram

66

What are miscellaneous Ectoparasiticides? (3)

Fipronil
Amitraz
Metaflumazone

67

SLUDGE symptoms

salivation, lacrimation, urination, defecation, GI distress and emesis.

*Organophosphate poisoning.