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132 Cards in this Set

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What are 6 lung worms that fenbendazole are effective against?
1) Aelurostrongylus
2) Crenosoma vulpis
3) Paragominus
4) Capillaria
5) Filaroides
6) Angiostrongylus vasorum
What kind of drug is febantel?
Prodrug-metabolized to fenbendazole and oxfendazole
What is the only form that febantel is available in?
Only available in combination with praziquantel and pyrantel= drontal plus
What is the spectrum of activity of febantel? (3)
1) Roundworms
2) Hookworms
3) Whipworms (dogs)
What is the mechanism of action of tetrahydropyrimidines?
Nicotinic agonists
-Act selective on parasite Ach receptor
-Causes depolarization--> contraction and tonic paralysis
How is pyrantel administered?
Well absorbed orally
When does the peak plasma concentration of pyrantel occur?
3-6 hours
What are the adverse effects of pyrantel in small animals?
Well tolerated and safe
What is the spectrum of activity of pyrantel? (3)
1) Roundworms
2) Hookworms
3) Physaloptera
Pyrantel has synergistic activity with _______.
Febantel
--> increased activity against hookworm and whipworm
What are the 2 advantages of piperazine? Disadvantage?
Safe
Inexpensive
-Only active against roundworms
What is the only arsenical anthelmintic approved in the US?
Melarsomine
What is the spectrum of activity of melarsomine?
92-98% efficacy against adult heartworm in dogs
-Contraindicated in cats
How is melarsomine administered?
Deep IM injection
What are the 2 dosage intervals used to administer melarsomine? What's the advantage/disadvantage of each?
1) 2 injections 24 hours apart
-Low risk of thromboembolism
2) 3 injections
-Single injection followed by the 2 standard injections
-High risk of thromboembolism
When are the peak concentrations of melarsomine established? Half life of melarsomine?
Peak blood levels in 11 minutes
-Half life: 3 h
1/3 of dogs injected with melarsomine develop a _______ reaction.
Local injection
What are 7 adverse effects of melarsomine?
1) Increased liver enzymes
2) Coughing
3) Gagging
4) Anorexia
5) Fever
6) Pulmonary congestion
7) Vomiting
What is the therapeutic index of melarsomine like?
Very narrow therapeutic range
-Parasite removal by poisoning the patient just enough to kill the parasite...
What are 3 external parasiticides that are only used in dogs?
1) Spinosad (Comfortis)
2) Amitraz + metaflumazone (Promeris)
3) Milbemycin + lefenuron (Sentinel)
What are the 2 groups of antiparasitic drugs that are macrolides?
1) Avermectins
2) Milbemycins
What are 2 avermectins used in small animal medicine?
1) Ivermectin
2) Selamectin
What are 2 milbemycins used in small animal medicine?
1) Milbemycin
2) Moxidectin
What is the structure of ivermectin? Selamectin?
Ivermectin: dissacharides
Selamectin: monosaccharides
How does the structure of milbemycins vary from avermectins?
No sugar substituents
(Ivermectin-disaccharide, selamectin-monosacharide)
What are the 2 common mechanisms of action in avermectins and milbemycins?
1) Agonists of glutamate-gated-Cl-channel-->
-Muscle hyperpolarization
-Flaccid paralysis
2) Agonists of GABA-gated-Cl-channel-->
-Muscle hyperpolarization
-Flaccid paralysis
Why aren't the glutamate-gated-Cl-channels of mammalian cells affected by avermectins and milbemycins?
The channel targeted isn't present in mammals
Why aren't the GABA-gated-Cl-channels of mammalian cells affected by avermetins and milbemycins?
Blood-brain barrier protects mammals
What is the spectrum of activity of ivermectin in small animals? (3)
1) Roundworm
2) Hookworm
3) Heartworm
-Prevention
-Microfilaricide (dogs
-Adulticide (w/ doxycycline)
What is the spectrum of activity of selamectin in small animals? (3)
1) Roundworm
2) Hookworm (cats)
3) Heartworm
-Prevention
What is the spectrum of activity of milbemycin in small animals? (4)
1) Roundworm
2) Hookworm
3) Whipworm (dogs)
4) Heartworm
-Prevention
-Microfilaricide (dogs)
What was the first commercially-available macrolide?
Ivermectin
What is oral absorption of ivermectin like?
Rapid oral absorption
When are peak plasma concentrations of Ivermectin established?
Peak: 4-10 h
What is the half life of ivermectin?
1.8 days
What are 6 adverse effects of ivermectin?
1) Mydriasis (>2.5 mg/kg)
2) Tremors (>5 mg/kg)
3) Stupor to coma
4) Ataxis
5) Seizures
6) Death (>40 mg/kg)
What is the LD50 of ivermectin?
80 mg/kg
Why are some dogs sensitive to ivermectin?
MDR gene mutation interferes with metabolism and allows drug to get through BBB to CNS
What are 5 breeds of dogs that have the MDR gene mutation and ivermectin should not be used in?
1) Collies (70%)
2) Longhaired whippet (65%)
3) Australian shepherd (50%)
4) Shetland sheepdog (15%)
5) German shepherd (15%)
Compare the dose of ivermectin needed for prevention and microfilaricide compared to killing worms.
Prevention and microfilaricide: 0.05 mg/kg
Worms: 0.2-0.6mg/kg
Compare the dose of ivermectin neded for heartworm prevention compared to lung worms (Aelurostrongylus).
Prevention: 0.024 mg/kg once monthly
Aelurostrongylus: 0.4 mg/kg once
What is the only macrolide approved for internal and external parasites?
Selamectin
What is the heartworm prevention of choice in collies?
Selamectin
True or false. Selamectin is effective against Aelurostrongylus in cats.
True
What is the bioavailability of selamectin in dogs? cats?
Dogs: 4%
Cats: 74%
What is the half life of topical selamectin administration in dogs & cats?
Dogs: 11 d
Cats: 8 d
What are the pharmacokinetics of milbemycin (absorption, peak, half life)?
Similar to ivermectin
-Rapid oral absorption
-Peak concentration: 4-10 h
-Half life: 1.8 d
What are 5 uses of milbemycin at 0.5mg/kg in dogs?
1) Heartworm prevention (cats too) & microfilaricide
2) Roundworms, hookworms, whipworms
3) Baylisascaris procyonis (raccoon roundworm) in dogs
4) Pneumonyssoides caninum (nose mites)
5) Demodicosis
What is a use of milbemycin at 2 mg/kg?
Sarcoptes scabiei
What dose of milbemycin is well tolerated? in collies?
200 mg/kg
Collies: 10 mg/kg
In small animals, moxidectin is formulated with _______.
Imidacloprid
-ProHeart 6 is available only through a restricted distribution program
What is the oral absorption of moxidectin like? Peak concentrations? Half-life?
-Rapid oral absorption
-Tmax at 2-3 hours
-Elimination half-life: 19 days
What are 2 isoquinolones that are closely-related cesticides?
1) Praziquantels
2) Epsiprantel
What is the mechanism of action of isoquinolones?
-Increases cell membrane permeability to calcium-->
Loss of intracellular calcium-->
Contraction and paralysis
-vacuolization and destruction of protective tegument
Praziquantel has marked activity against what 3 parasites?
1) Dipylidium
2) Taenia
3) Echinococcus
What is oral absorption of praziquantel like?
High oral bioavailability, but marked first pass effect
True or false. Praziquantel is highly protein bound.
True
What is the oral half-life of praziquantel?
30 m to 3 h
True or false. Praziquantel has a narrow therapeutic index.
False, very safe drug
Epsiprantel is similar to which drug?
Praziquantel
What is the oral absorption of epsiprantel like?
Poorly absorbed orally
What is the spectrum of activity of epsiprantel?
Active against Dipylidium & taenia
-Potentially against Echinococcus: data insufficient to recommend a dosage that will clear the infection
How is epsiprantel administered?
Oral film-coated tablet
What are the 3 advantages of broad spectrum combinations of antiparasitics?
1) Increased spectrum
2) Easier administration
3) Client satisfaction
What animal is emodepside + praziquantel used in?
Spot-on product for use in cats that comes in prefilled applicators
What animals is Emodepside + praziquantel used in?
Cats & kittens > 8 weeks of age
What is the spectrum of activity of Emodepside + praziquantel? (3)
1) Roundworms
2) Hookworms
3) Tapeworms
What are the active ingredients of Virbantel and Drontal?
Pyrantel + praziquantel
What is the spectrum of activity of virbantel and drontal (pyrantel + praziquantel)? (3)
1) Tapeworms (Taenia, dipyllidium, echinococcus)
2) Roundworms
3) Hookworms
What is different about feline and canine drontal dosing?
Dogs get 5 mg/kg of both pyrantel and praziquantel
Cats get 5mg/kg of pyrantel and 20mg/kg of praziquantel
What are 2 situations where Drontal should not be administered to a cat?
Cats weighing less than 0.8 kg
Kittens younger than 4 weeks of age
What are the 3 active ingredients of Drontal Plus?
1) Pyrantel
2) Praziquantel
3) Febantel
What is the spectrum of activity of Drontal plus? (4)
1) Tapeworms (including Echinococcus)
2) Roundworms
3) Hookworms
4) Whipworms
What are 3 contraindications for Drontal Plus?
1) Pregnant dogs
2) Dogs weighing less than 1 kg
3) Puppies younger than 3 weeks of age
Why is pyrantel combined with Ivermectin?
To provide activity against hookworms and roundworms
-Ivermectin dose=heartworms
True or false. Ivermectin + pyrantel is safe to use in collies.
True
Why can't ivermectin + pyrantel kill GI parasites?
Ivermectin is too low of a dose for GI parasites
How often is Ivermectin + pyrantel administered?
Given at monthly intervals during heartworm season
Why is praziquantel added to ivermectin + pyrantel?
To provide activity against tapeworms
What are 5 external parasiticides used in small animals?
1) Macrolides
2) Phenylpyrazoles
3) Neonicontinoids
4) Spinosads
5) Insect-growth regulators (IGR)
Macrolides are potent _________, but are also active against _______.
Potent anthelmintics
Active against arthropods: insects, mites, ticks
What are 3 macrolides that are effective against external parasites?
1) Ivermectin
2) Selamectin
3) Milbemycin
What are the 4 external parasites that ivermectin is effective against?
1) Canine & feline scabies
2) Demodicosis
3) Cheyletiellosis (type of mite)
4) Ear mites
What are 2 external parasites that milbemycin is effective against?
1) Canine & feline scabies
2) Demodicosis
What are 5 external parasites that selamectin is effective against?
1) Canine & feline scabies
2) Ear mites
3) Ticks
4) Fleas
5) Lice
All 3 macrolides (Ivermectin, selamectin, milbemycin) have activity against what external parasite?
Canine & feline scabies
What is the mechanism of action of Fipronil?
Inhibits GABA-regulated chloride flux
What is the spectrum of activity of fipronil (Frontline)?
-Flea adulticide
-Activity against ticks & lice
What are the 2 routes of administration available for fipronil?
1) Spray
2) Spot-on (frontline)
What is the mechanism of action of neonicotinoids?
Act selectively on insect acetylcholine receptor (nAChR)
What are 2 anti-parasitics that have a mechamism of action that acts on parasite Ach receptor (nAChR)?
1) Tetrahydropyrimidines (nicotinic agonist=nematodicide)
2) Neonicotinoids
What are 2 neonicotinoids?
1) Imidacloprid
2) Nitenpyram
How is Imidacloprid administered?
Spot-on application for dogs and cats
What is the spectrum of activity of imidacloprid (Advantage)?
Adulticidal activity against fleas
-Lasts up to 4 weeks
Imidacloprid has a therapeutic margin of at least ____-fold.
20 fold
How is Nitenpyram administered?
Oral product for dogs & cats
-Rapid absorption
What is the half life of Nitenpyram in dogs? Cats?
Dogs: 2 hours
Cats: 16 hours
What is the spectrum of activity of nitenpyram?
100% activity against adult fleas
for 24 hours
How is Spinosad administered? What's its spectrum of activity?
Oral product to control fleas in dogs only
-No activity against ticks
Spinosad is not to be used in combination with _______.
Ivermectin
How old do dogs have to be to use Spinosad?
> 14 weeks of age
What is the spectrum of activity of IGR? Mechanism of action?
Controls early stages of flea metabolism, morphogenesis and reproduction
-NO direct adulticidal activity
-Interrupt environmental stage of flea life cycle
IGR is usually combined with an ______.
Adulticide
e.g. Advantage=pyriproxifen + imidacloprid
What are 3 IGRs?
1) Lufenuron
2) Methoprene
3) Pyriproxifen
What is the mechanism of action of lufenuron?
Inhibits synthesis and deposition of chitin within the ova and larval exoskeleton of developing fleas
-Taken up by the feeding flea and incorporated into the developing egg
What is the mechanism of action of methoprene?
Flea juvenile hormone analog
What is the mechanism of action of pyriproxifen?
Juvenile hormone mimetic for fleas
-In advantage with Imidacloprid
How is amitraz + metaflumazone administered? What animal?
Spot-on product for dogs > 8 weeks of age
What are the 3 uses of amitraz + metafluazone?
1) demodicosis
2) fleas
3) ticks
-Market name=Promeris
Milbemycin + lufenuron is approved for use in _______.
Dogs
What is the spectrum of activity of milbemycin + Lufenuron in dogs? (5)
1) Heartworm prevention
2) Hookworms
3) Roundworms
4) Whipworms
5) Controls fleas
Why is imidacloprid added to moxidectin?
Imidacloprid is added for flea control
-All together covers: round worms, hook worms, whip worms, heart worms, ear mites, fleas
True or false. Imdacloprid + moxidectin is a product only approved for use in dogs.
False, there is a feline product, but the canine product CANNOT be used in cats.
Marketed as: Advantage-multi
What is the spectrum of activity of Imidacloprid + moxidectin? (6)
1) Heartworm prevention
2) Roundworms
3) Hookworms
4) Whipworms (dogs)
5) Fleas
6) Ear mites (cats)
-Marketed as: Advantage-multi
What is a very common cause of large bowel diarrhea in adult dogs?
Whipworms
-So deworm a dog with diarrhea before performing endoscopy
What are 4 nematicides used in small animal medicine?
1) Macrolides
2) Benzimidazoles
3) Tetrahydropyrimidines
4) Arsenicals
What is 1 cestocide used in small animal medicine?
Isoquinolones
What are 2 reasons that parasites are important in veterinary medicine?
Zoonosis
Disease
e.g. whipworms cause diarrhea in adult dogs
Benzimidazoles are a large family of _____ spectrum agents.
Broad
What is the mechanism of action of benzimidazoles?
Bind to beta-tubulin--->
inhibits tubulin polymerization in susceptible helminths (nematicide)
Why are benzimidazoles so safe to use in mammals?
25-400 fold lower inhibition constant for mammalian tubulin
-So takes HIGH dose to damage mammal tubulin
How are benzimidazoles administered in small animals? How often?
Poorly soluble, given by mouth
-Faster GI transit in SAs, so requires multiple dosing (3 or more days)
True or false. Benzimidazoles are commonly used in small animal medicine.
False, except still use albendazole, but causes GI issues so only use when really needed
True or false. Albendazole in small animals is extra label use.
True
What is oral absorption of albendazole like?
Well absorbed orally
What are 4 adverse effects of albendazole?
1) Teratogenic
2) Myelosuppression
3) Ataxis
4) *Vomiting & diarrhea
What is the spectrum of activity of albendazole? (4)
1) Roundworms
2) Hookworms
3) Lungworms
4) Capillaria plica
What is the spectrum of activity of fenbendazole? (5)
1) Roundworms
2) Hookworms
3) Whipworms (Dogs)
4) Lungworms
5) Giardia
What age does a dog have to be in order to use fenbendazole?
Approved for use in dogs 6 weeks of age or older
What are the adverse effects of fenbendazole?
Rare cases of bone marrow hypoplasia
-Very safe drug
How long does fenbendazole have to be given to kill intestinal worms in dogs & cats? For giardia
Dogs: 3 days
Cats: 5 days
Giardia: 5 days
What drug can be used to treat Baylisascaris procyonis infection in a dog?
Milbemycin (0.5 mg/kg)