Ectoparasiticides

Front 1

What are the advantages and disadvantages of using tags, tapes and collars V spot ons and pour ons

Back 1

tags- adv. less work, but resistance when run low and poor release
pour- non invasive but may over dose

Front 2

organophosphate MOA

Back 2

the leaving group permanently inhibits AChE selectively but not specific to ectoparasites.

normally the AChE is inhibited by an ACh for a short time before being hydrolysed ( reactivated). Organophosphates eventually bind permanently ( called aging) and they phosphorylate the AChE

Front 3

organophosphate spectrum

Back 3

broad. flies/fleas/lice/ticks/mites

Front 4

organophosphate toxicity and antidote and any percautions.

Back 4

narrow margin for man and animals -high risk of acute toxicity for animals and man, with muscarinic, nicotinic and central effects because of the excess ACh. seen more in humans eg Muscarinic - DUMBELS- Diarrhoea, Urination, Miosis, Bronchoconstriction, Emesis, Lacrimation, Salavation

atropine and oxmides as antidote. LIKE AandE ! except o!

time restriction- warble flies overwinter in SC and oeso. so only use in summer.
age restriction ( young / old more S)
other drugs ( AChE inhibitiors eg carbamates)
care with handling ( people and environment)
resistance

LIKE AN OP JUST WANTS TO STAY FOR EVER AND TALK!

Front 5

organophosphate use and administration

Back 5

sheep dips ( scab and flies)- long 70 day withdrawl
cat/dog flea collar ( only a GSL)
fish ( sea lice)

topical (dips/sprays)
systemic ( pour on /spot on)
collars/tapes/tags

Front 6

organophosphate antidotes and MOA of these

Back 6

Atropine- non specific muscarinic antagonist
oxmides- speeds up reactivation of AChE - esp important with drugs which cause AChE to age quickly eg Parathion. ( it transfers the phosphate away from the AChE )

Front 7

carbamates MOA and difference/ simularities to organophosphates

Back 7

binds reversibly to AChE in certain parasites only and more persistent in insests ( unlike organophosphates) Enzyme intermediate is also caused by phosphorylation but the half like before reactivation is only around 20 mins V days in orrganophosphates also there is no aging of the enzyme.

Front 8

carbamates spectrum

Back 8

broad ( ticks/mites/lice/fleas)

Front 9

carbamates toxicity and antidotes

Back 9

carcinogenic. However less toxic than organophosphates as its phosphorylated intermediate has a shorted half life and its binding is reversible. also not presistant in the environment.
antidotes - only atropine

Front 10

why is atropine used by it self as anantidote for carbamates whereas it is used with oxmides for organophosphates

Back 10

AChE can regenerate so does not need oxmides

Front 11

carbamates use

Back 11

cats/dogs ( lice/ fleas/ticks/mites)( GSP- general sales list. collar or sprays -less)

Front 12

pyrethrins and pyrethroids MOA

Back 12

binds to Na channel at presynaptic membrane and keeps it open, allowing an AP to form causing spastic paralysis. Quick penetration but quickly broken down by enzymes so needs to be given with PBO which inhibits its metabolism so allows it to have a longer exposure time to have its lethal effect

Front 13

pyrethrins and pyrethroids Spectrum

Back 13

broad. ( lice/fleas/flies/keds)
pyrethroids also do ticks and mites

Front 14

pyrethrins and pyrethroids toxicity

Back 14

selective toxicity - humans met. it quickly so not toxic.
low if given orally ( except some sp.).
V.Toxic if injected.
fish and some aquatic vertebrates are succeptible.
pyrethroids- type 1 and type 2
type 1... if there is no alpha cyano group present- 't syndrome' whole body tremor, exagerated startle reflex, muscle twitch.
type 2 ... if alpha cyano group is present met. will be slowed and toxic effects will be salavation, uncordination, spasms, apnea, seizures and death

note the pyrethroids Cis isomer is more toxic ( there will be a mixture of CIs and trans)

degree of toxicity will depend on the age, species, fasting status. CATS- susceptible to permethrin type 1 syndrome as they cant metabolism it properly. this may occur if dog collars are used on cats- treated with methocarbamol IV ( a muscle relaxant )

Front 15

Avermectins and milbemycins spectrum

Back 15

some are endectosides. eg dextomax for cattle sheep and pigs. sucking lice/some mange mites/warbles

Front 16

avermectins and Milbemycins MOA

Back 16

peripheral Glutamate and or GABA gated chloride channels which cause flacid paralysis due to influx of chloride. ( note these channels are central in Humans).

Front 17

avermectins and Milbemycins toxicity

Back 17

some dog breeds, kittens, some bird sp. and turtles fish and reptiles.

Ivermectin- toxocosis symdrome ( mydriasis, depression, tremor, ataxia, emesis, salavation and coma.dogs with MDR1 mutation who lack the pump. ( collies, german s, auz. S and others...)

other avermectins are largly free of these porblems

Front 18

Amidines ( amitraz) MOA

Back 18

octopamine receptor antagonist ( affects behaviour of the ectoparasite so it does not seek the host) also alpha 2 receptor agonist. This inhibits tick MAO leading to hyperactivity and detaching behavior .... decreased fecundity, inhibits ovi-position and egg hatch-ability

Front 19

Amidines adverse effects and treatment

Back 19

transient sedation about 12-14 hrs after treatment
puritis in some dogs.high exposure- depression andsedation , polyurea and bradycardia, GI stasis ( horses- not licenced)

cats - countraindicated ( as cant metabolise) note only for dogs.also contraindicasted in chihuahuas and dogs with heat stress

treatment is with an alpha 2 agonist

Front 20

cyromazine and methoprene MOA

Back 20

IGR -insect growth regulators. effect the deposition of chitin in cuticle or juvenile insect hormone

Front 21

benzoyl urea derivative MOA

Back 21

inhibits chitin synthesis. systemic so require flea to bite

Front 22

benzoyl urea derivatives spectrum

Back 22

fleas. larvicidal and ovicidal

Front 23

benzoyl urea derivatives distribution

Back 23

food increases Ab.
builds up in fat as highly lipophilic

Front 24

Fipronil MOA

Back 24

antagonist to GABA and glutamate gated chloride channels ( peripheral NS of insect and in our central NS so safe).lipophilic so reservoir in skin.

Front 25

fipronil spectrum

Back 25

fleas/ticks and mites in SAs.
kills the adults before they lay eggs

Front 26

fipronil toxicity

Back 26

mod. in rabbits.
highly toxic to some birds/fish/aquatic invertebrates

Front 27

neonicotinoids MOA

Back 27

Block ACh nicotinic receptors- paralysis.
needs to be ingested by insect.

Front 28

neonicotinoids spectrum

Back 28

fleas in SAs/ rabbits/ferrets

Front 29

neonicotinoids toxicity

Back 29

low

Front 30

metaflumizone MOA and spectrum

Back 30

Block voltage dependant Na channels causing paralysis- fleas

Front 31

oxadiazine insecticides MOA and spectrum

Back 31

Na channel blocker. ( activated in gut).

fleas

Front 32

name 3 drug combinations used as endectosides ( active compounds and trade name) and which species they are used for.

Back 32

frontline combo- (SAs, fipronil and methoprene)

Advantix ( dogs NOT cats, Imidacloprid and permethrin)

Adovocate ( SAs, Imidacloprid and moxidectin )