Anthelmintics Flashcards
What is the MOA of Benzimidazoles?
Binds to parasite B-tubulin subunit (microtubules)
- disrupts cell everything
- binds to mammalian cell but dissolved very quickly
What is the PK of benzimidazoles?
poor water solubility (pastes, suspensions, granules) poor oral F Distribution is high hepatic metabolism (CYP enzymes) - first pass effect Other distribution: lung and intestines
What are benzimidazoles used for?
GI and lung nematodes
some cestodes and some trematodes
What is the most common benzimidazole?
Fenbendazole (safeguard, pancur)
What is Fenbendazole used for on label?
horses (suspensions, pastes, granules)
cattle (suspensiosn, feed)
swine/chicken (pancur, aquasol in water)
dogs (pancur, granules)
What is fenbendazole used to treat?
GI and lung nematodes
- strongyles, ascarides, whipworms, hookworms, pinworms
What is fenbendazole used for off label?
small ruminants, turkeys
cats (nematode, giardia, lung worms)
birds, exotics
What is Febental?
fenbendazole prodrug
“drontal plus” (fenbental+pyrantel+praziquantel)
- used for dogs
What is another benzimidazole used for cattle? what is it used to treat?
Albendazole (Valbazen)
- adult flukes (not great choice)
- tapeworms
What other benzimidazole can be used for adult and juv flukes and lung worm?
Triclabendazole
What is an emergency drug release?
a way for vets to access drugs approved in other areas of the world
- need documented evidence and safety
NO FOR:
- biologics, investigation drug, comparable drug here
What is the MOA of macrocyclic lactones (ML)?
opens glutamate gated Cl channels (opposite as isoxaolines)
- Cl entry into cell (hyperpolarization)
= flaccid paralysis of worm
may bind to GABA receptors at high concentrations
What are MLs used for?
nematodes and arthropods
Exception: demodex and some adult filaria(higher doses)
- heart worm preventative (low dose ivermec)
minimal against cest and trem
What is the PK of MLs?
oral and transcuticular absorption from host (oral, topical, injectable) lipophilic with high VD - hepatic metabolism LONG withdrawal (most not for dairy)
What are some adverse effects of MLs?
toxicity with GABA stim in the CNS = neurosigns
-Tx: IV lipid emulsion
ABCB1 mutant dogs (white feed dont treat)
- decrease pgp increase distribution to brain
What are some Avomectin (ML) drugs? and what are they used for?
Ivermectin (ivomec)
- oral drench (sheep)
- oral paste (horses)
- pour on cattle)
- injectable (cattle, sheep, swine)
- oral premix (swine)
- tablets (dogs)
Eprinomectin
Eprinex - pour on
- license for dairy cows (no milk withholding)
Long-range (extended release SC)
- rapid and slow absorption
- 4-5m activity
- 4m meat withdrawal
- dont use for dairy
Doramectin (dectomax)
- injectable (cattle/swine)
- pour on (cattle)
- similar to ivermectin
Salamectin (revolution)
- monthly topical for dogs/cats
- fleats, mites (not demodex), nematodes, HW prevention
- safer than iver mec for ABCB1 mutants (still dont use)
- fish
What is a Milbemycin (ML) drug used?
Moxidectin
- cydectin pour on (beef and dairy), similar to
Ivermec/doramec
- Quest/Quest plus (oral gel horses), moxidectin +/- praziquantel, tapeworms + nematodes
- advantage multi (monthly topical, dogs, cats, ferrets), moxidectin +imidacloprid, HW prevention, fleas, ear mites, GI nematodes
- ProHeart (sustained release for dogs), HW prevention (6 months)
What moxidectin monthly tablets do they have on the market? What do they all protect from, what unique parasite do each add?
all for HW prevention, hookworm, roundworm
milbemax (cats) - milbemycin + praziquantel, addition of tapeworm
interceptor tablets (dogs/cats) - milbemycin, addition of whipworm
Sentinel tablets (dogs) - milbemycin and lufenuron, addition of whipworm and fleas
Trifexis tablets (dogs) - milbemycin and spinosad, addition of whipworm and fleas
What species is ML resistance most affecting/emerging? What parasites is it reported in?
SHEEP
emerging in cattle and horses
widely reported in cyathostomes and large strongyles
What is the mechanism of ML resistance?
induction of parasite efflux pumps (p-gp)
changes in Glu gated Cl channels
How do you test for resistance?
pre and post treatment FEC (if below 95% reduction = resistance)
What are the ecological impacts of ML resistance?
avermectins persist in feces and kill feces degrading insects
evaluated part of drug approval (excretion in non-toxic form helps.
What are some topical tips for ML?
skin not hair
watch for mud/feces
not low temps
flammable (branding)
What is the very old dewormer called thats used for everything but ruminants?
piperazine
- over the counter
What is the MOA, use and AE of piperazine?
MOA: anticholinergic activity in parasite muscular junction (hyperpolarization) and flaccid paralysis
USE: large round worms (ascarids)
AE: GI upset or neuro signs
What are the drugs in the Pyrimidine class?
Pyrantel
Praziquantel
Emodepsite
nitroscanate (lopatol - tablets)
Melarsomine (immiticide)
What is the MOA, use of pyrantel?
MOA: depolarizes NMJ, nicotinic receptor agonist, leads to spastic paralysis
USE: nematodes, some cestodes at higher doses
What are the different labels for Pamoate salt (paste suspension)
Drontal (cats)/Drontal Plus (dogs)
- praziquantel +/- febantel
Dolpac
- pyrantel
Heart guard Plus
- pyrantel + Ivermec (invermec lasts longer and is lower dose for HW preven)
exodus (equine) - oral paste
Strongid (equine) -pate or suspension
- large strongyles
- EL in small animals
What is the label for Tartrate salt (solution)?
Pro-Banminth Premix (swine)
- ascaris suum
What is the MOA, use, and AE of Praziquantel?
MOA: increase in ICF Ca = spastic paralysis
Use: anti-cestode drugs for cat, dog, horses, cattle
- in combo with nematode or alone
AE: CYP drug interaction (inhibit Pgyp transporter)
grapefruit juice increses F
What is the MOA, use and AE of Emodepside?
MOA: intracellular signal transduction = flaccid paralysis
Use: round, hook and tape
- safe for pregnany queens
AE: mild GI, watch for pgyp interaction
What is the use and AE of Nitroscanate (lapotol)?
dogs for round, hook and tape
increased absorption with food
- safe in young puppies
AE: vomiting
What is the use of Melarsomine?
dogs only
killed dirofilaria immitis adult
deep IM injection (epaxial muscles only)
NASTY DRUG
