Pharm 2- Ectoparasites

kelseyfmeyer's version from 2015-05-10 01:47


Question Answer
*(also key note)what are the routes of dermal absorption, and which is most common?Transcellular, Intercellular (most drugs are absorbed this way), Transfollicular, Sweat pores, Lateral diffusion
Mechanisms of insect resistance include↓ penetration of the drug, ↑ activity of detoxifying enzymes (cross resistance between classes of drugs), ↓ sensitivity of the target site (changes in Na channels lead to diminished binding of pyrethroids)
Key note: Mechanism of action of ectoparasiticides: (3 things, some have subtypes)(1) Ectoparasite nervous system: AChE-inhibitors, Na+ channel blockers, nAChR inhibitors, GABA and Cl- channel inhibitors (2) Ectoparasite repellents (3) Insect growth and development inhibitors
Mechanism of insect resistance include (3)(1) Decreased penetration of the drug (2) Increased activity of detoxifying enzymes (the cause of cross resistance between classes of drugs) (3) Decreased sensitivity of the target site (changes in Na+ channels lead to diminished binding of pyrethroids)


Question Answer
MOA of fipronil?Non-competitive block of the GABA and glutamate ion channels (Fi likes to GAB when she eats sugar)
what does fipronil treat?Treats adult fleas and different stages of a variety of ticks (Fi can only handle so much...F for her name, and T so she can be FIT)
firponil in what animals?dogs and cats
contraindications of fipronil?DO NOT USE IN YOUNG RABBITS (Fi hates rabbits-- FIP THE HARE LIP)
things to note about fipronil?FLEAS AND TICKS MUST BITE FIRST (Fi is covered in bug bites)
has fipronil been combined with anything?Has been combined with IGR (Fi didnt want to get fat, so she has to use Growth Regulators)
how safe?*wide safety margin, less affinity for mammalian GABA (Fi wouldn't hurt an animal)


Question Answer
what are the two drugs in this group?Imidacloprid, Nytenpyram (clop clop, nyaaannn)
MOA of Imidacloprid?Competitive inhibition of post-synaptic nicotinic receptors (nAChR) (clop right through the nicotine addiction)
admin of imidacloprid? absorption?Topical--> does not absorb into the skin (lateral diffusion) – lg. safety margin (it is advantage or whatever when combined with the permerthin or whatever)
imidacloprid/nytenpyram is used for treating? how effective?adult and larval fleas--> RAPID DEATH (only fleabags care about cigarettes)
thing to note about imidacloprid?PREVENTS biting (also tx fleas resistant to fipronil) (clop it right in the face before it bites)
has imidacloprid been combined with anything?Combo w/ permethrin = repel and kill misquotes and ticks on adult dogs (ADVANTIX) (perm your pet clop--it will look like it's from the 80s)
admin of Nytenpyram?Oral, 100% absorption (you say nyan with your mouth)
contraindications of neonicotinoids?DO NOT USE IN CATS (cats are bitchy enough without a nicotine addiciton)
how safe?wide safety margin (but don't use in cats) (that's a wide clop you made there-- musta been painful)

Macrocyclic Lactones (also antinematodal with ectoparasite activity)

Question Answer
MOA of Avermectins?Targets ~glutamate, GABA, and glycine gated ion channels (Good Going God, for making MyDumbRetard)<--as much as I don't like using that word, I will do whatever it takes to learn this shit
contraindications of avermectins?NOT USED be used in collies, bobtails, shelties---> *toxicity in collies, bobtails, shelties (have the MDR1 mutation) because they target the GABA receptor (mydumbretarded1---> stupid collies, shelties and bobtails)
which drugs are in the oil pour-on preparations?erpinomectin and moxidectin (primo milk on the skin and the moxi to go on any way it wants)
spectrum of activity of macrocyclic lactones?broad (mac and his broad shoulders)
which drugs have no withdrawal for milk?eprinomectin and moxidectin (the same ones as oil pour on...and primo milk, moxie to do what it wants with no concenquences)
which animal/breed is very susceptible to macrocyclic lactones?Dog breed with an MDR1 gene mutation

Organophosphates and carbamates(<--BZDs, the most effective ones)

Question Answer
MOA of carbamates?Reversible inhibition of AcH esterase (because carbamates are like organophosphates, even tho the anthelmentics say otherwise. also reversible means less toxic)
when are carbamates unstable?Relatively unstable in alkali environments (cars and organs are not basic things for life)
what do carbamates treat?Used against lice, fleas, ticks and sometimes mites (a car full of everyone-- lice, fleas, ticks, AND sometimes mites, if you want the 4th seat filled up)
what are the drugs in carbamates?Carbaryl, Propoxur, Bendiocarb
MOA of organophosphates?Irreversible inhibition of AcH esterase (remember? just like dichlorvos) (irreversible is also why it's more toxic)
when are organophosphates unstable?Unstable in alkali environments (cars and organs are not basic things for life)
which is more toxic, organophosphates or carbamates? what are the clinical signs?organophosphates are more toxic than carbamates (...they are powerful pesticides, makes sense theyre more toxic) clinical signs similar to stimulation of parasympathetic nervous system
how soluble are organophosphateS?poorly water soluble (poor water solubility, when was the last time you saw an organ dissolve in water)
what do organophosphates treat?Used against lice, fleas, ticks and sometimes mites
what are the drugs in organophosphates?Coumaphos, Fenthion, Famphur, Diazinon, Phoxim, Phosmet, Cythioate
sensitive animals?brahaman cattle, grey hounds, cats
odd side effect?delayed neurological effects (can be nicotinic or muscarinic)
carbarylspray and dust for dogs and cats
propoxurflea collars for dogs and cats
OP--> coumaphos--> doesnt tx what?ticks

Formamidines (amitraz)

Question Answer
MOA of amitraz?Inhibition of monoamino oxidase, Agonistic effects on the α2 – receptors, Agonists of the insect’s octopamine receptors (so...MAO AmiAmi <--ax2 and she will eat an octopus)
tox of amitraz presents as?Intoxications is characterized by α2 – adrenergic effects such as sedation and colon obstipation ((Ami's trax marks indicate when she ODs, she must be extremely sedated and constipated)
who is sensitive to amitraz?Horses and cats are sensitive (horses and cats are sensitive about Ami having traz marks on her arm)
do NOT use amitraz in who?DO NOT use in Chihuahuas, pregnant or nursing bitches or puppies less than 3 months old (extremely tiny things, or things that have to deal with very tiny things. because AMI WILL CRUSH THEMMMMM)

Insect Development Inhibitors (IDIs)

Question Answer
MOA?Inhibition of chitin synthesis, Larvicidal--- Interfere with the synthesis of the exoskeleton (egg shell and larval development) (can't develop with no exoskeleton or egg)
what are the three drugs in this category?Lufenuron, Flufenoxuron, Diflubenzuron
How can you improve oral bioavail of IDIs?enhanced with food
which IDI is highly protein bound?Lufenuron (Lu thinkts it's fen eating protein)
contraindications of IDIs?Do not use in lactating animals
Lufenuroninhibits chitin synthesis - exoskeleton development

Insect Growth Regulators (IGRs)

Question Answer
MOA?Interferes with the hormonal regulation of the maturation process of larvae (larvicidal)-- Agonists of the juvenile hormone (cant grow without juvenile hormones)
what do you combine with these, and what do these treat?Used in combination with adulticides in the treatment of fleas (stopping form growing doesnt help with fully growns)-- and GrowFleas for alphabetical order
which drug in this category is susceptible for larval esterases?S-methopreen (ES-METH for ESTER...i mean easter)
methoprenejuvenile hormone analogue (Meth will stunt your growth for sure)

Pyrethrins & (synthetic) Pyrethroids

Question Answer
MOA?Interacts with the Na+ channels---- Targets voltage gated Na channels in axonal membrane; GABA gated Cl channels; mitochondrial ATPase and nicotinic receptors (put salt on a python it will shrivel up like a gabbing nicotine addict)
how does resistance occur in the pyrethrins and pyrethroids?Resistance --> mutations in Na channels = ↓ binding of the ectoparasiticide to the Na channel
what is the safety like for pyrethrins and pyrethroids, and why is it like that?Minimal systemic absorption after dermal application --> NO food and milk withdrawal time (pythons arent going to be in your milk and meat)
admin? why benifit is related to it's PK and the admin?topical/dermal-- Minimal dermal uptake - minimal withdrawal time
contraindications?DO NOT use in cats --> grooming --> ingestion. Also Aquatic animals= highly sensitive. (pythons will eat cats and fishes easily)
treats what?fleas, lice, mites, and ticks (repellent effect on flies) (pythons will eat anything)
Allethrin and Phenothrin are used for what?Used as a spot-in formulation against fleas and ticks in dogs (Dogs get ALL the PHEN)
Resmethrin and Permethrin... note about these?Short withdrawal time (The Res is Permanant....unless we withdrawal it, which would give it a short time)
Fenvalerate...note about these?used in ear tags for cattle (FEN for VAL to put earrings on cows)
Flumethrin and Cypermethrin...note about these?Used as fly repellent spray in horses (horse flew pass the cypresses, repelled by the fire)
fenvalerate note about side effects?serious side-effects at low doses

isoxazoline ectoparasiticides and oclacitinib

Question Answer
what is the drug in the isoxazoline exctoparasitisets?fluralaner (FLURNER ERH MER SERKS)
MOA of fluralanerSelective inhibition of arthropod GABA and Lglutamate- gated chloride channels--> Binding within the chloride channel lumen-->Similar effects as fipronil but different class of drugs (Fi like fluras-- flur same as fipronil MOA)
Oclacitinib is used for what? MOA?new anti-itch drug--> Mechanism of action: inhibition of JAK-1 (Janus kinase-1)--> Inhibits activation of nerve cells and immune cells by cytokines (Janus lacktit)