Transcript Antiparasitics

Antiparasitics
Antiparasitics…
• Make up the largest category of products available to veterinary
professionals and the general public
• Can be OTC or Rx
• Help to protect animals from diseases, as well as people
• Is an important topic of client education for veterinary technicians
(let them look under the microscope, show them a heart filled with
worms)
• Is a quickly changing market
The ideal paraciticide is….
• Selectively toxic to the parasite and not the host
• Does not induce resistance in the target parasite
• Is economical
• Effective against all parasite stages with one application
• Fragrant or odorless
• Environmentally safe
General rules of antiparasitics
• Use with caution in old, young, debilitated, or pregnant animals
• Certain antiparasitics are risky for certain groups of animals
• They are only effective if most of the drug reaches the location
of the parasite
• The client and veterinary team must understand which part of
the parasite’s life cycle is affected by the drug and how/ when
the drug should be applied
Terms
• Endectocides: have the ability to kill endoparasites and ectoparasites
– Endoparasites cause infections, ectoparasites cause infestations
– Parasites in an abnormal location in a hosts body are aberrant
• Anthelmintics: kill helminth worms (parasitic worms)
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Vermicide: kills the worm
Vermifuge: paralyzes the worm
Antinematodals: treat round worms
Anticestodals: treat tapeworms or segmented flat worms
Antitrematodals: treat trematodes flukes/unsegmented flat worms
• Antiprotozoals: treat single-celled organisms: coccidian, giardia,
Toxoplasma
DRUGS THAT TREAT ENDOPARASITES
• ANTHELMINTICS
– Antinematodals
– Anticestodals
– Antitrematodals
• ANTIPROTOZOALS
• ADULTICIDES and HEARTWORM PREVENTION
ANTINEMATODALS
• BENZIMIDAZOLES
• Attack beta tubulin which is a protein that is needed for cellular metabolism and cell
division
• Usually have to apply more than one dose consecutively
• In addition to nematodes, some products can treat some flukes, cestodes, and protozoa
• Used in large animals, small animals, snakes, birds, rodents (note: not approved for cats,
but is used)
• Oral pastes
• Side effects uncommon, but may include vomiting/diarrhea
• Have “azole” at the end of name
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Thiabendazole (EQUIZOLE, TBZ, OMNIZOLE)
Fenbendazole (PANACUR/SAFEGUARD)
Oxibendazole (ANTHELCIDE EQ)
Albendazole (VALBAZEN)
Oxfendazole (BENZELMIN)
Mebendazole (TELMIN)
ANTINEMATODALS
• ORGANOPHOSPHATES and CARBAMATES
– Inactivate acetocholinesterase in parasites. This allows acetylcholine to
overstimulate the nervous system and eventually cause paralysis (label
usually says “contains a cholinesterase inhibitor”).
– Originally used as nerve gas. Not used as often with animals as they used
to be.
– Break down quickly when exposed to light, air, and soil
ANTINEMATODALS
• ORGANOPHOSPHATES and CARBAMATES
• Used in large animals and small animals and also on plants
• Examples: Trichlorfon, Coumaphos (BAYMIX), Haloxon, Dichlorvos (TASK)
• To remember signs of toxicity, think SLUDDE (salivation, lacrimation,
urination, defecation, dyspnea, emesis). Also bradycardia, miosis, muscle
tremors, ataxia, paralysis
• Treat with ATROPINE or GLYCOPYRROLATE (block receptors for
acetylcholine) and remove the insecticide. Glycopyrrolate reverses the
neurological signs bc it crosses the blood brain barrier better than
Atropine does.
ANTINEMATODALS
• TETRAHYDROPYRIMIDINES
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Cause paralysis of the parasite
Large and small animals
Most commonly used one is Pyrantel pamoate (NEMEX, STRONGID)
Considered to be very safe
Often found in feed stores
Ineffective against tape worms
• IMIDATHIAZOLES
• Large and small animals and some exotics
• Examples include Febantel and Levamisole
• Can cause foaming at the mouth
ANTINEMATODALS
• Macrolides: Avermectins and Milbemycins
• Structurally similar with a macrocyclic ring that are derived for a Streptomyces
bacterium.
• Stimulate glutamate receptors in nematodes, causing paralysis and death.
• Among the safest compounds to use in mammals (these receptors are located
behind the blood-brain barrier within the CNS in mammals)
• AVERMECTINS
• Large and small animals, birds, and snakes
• Ivermectin, Selamectin, Doramectin, Eprinomectin
ANTINEMATODALS
• Ivermectin
• HEARTGARD, EQVALAN, IVOMEC
• Heartworm prevention, intestinal parasites, demodex, ear mites
• Oral or injectable
• Ivermectin toxicosis in collies
• Genetic (recessive) trait that causes a deficiency of P-glycoprotein, a protein that
moves drugs from the blood brain barrier cells back into the blood
• Signs of toxicosis are CNS depression (ataxia, mydriasis)
• Heartgard doses are safe
• No antidote
ANTINEMATODALS
• Selamectin
• REVOLUTION
• Heartworm preventation, internal parasites, flea
control, ear mites, sarcoptic mange (dogs), ticks (dogs)
• Topical
ANTINEMATODALS
• Doramectin
• DECTOMAX
• Internal worms, grubs, lice, mange
• Injectable and pour-on for cattle and swine
• Eprinomectin
• EPRINEX
• Internal worms, grubs, lice, mange
• Pour-on for cattle
ANTINEMATODALS
• MILBEMYCINS - Milbemycin oxime and Moxidectin
– Milbemycin oxime
• INTERCEPTOR, SENTINEL
• Heartworm preventative, hookworms, roundworms,
ear mites, mange
• Oral tablet for dogs and cats
– Moxidectin
• QUEST, CYDECTIN
• Nematodes, mites, grubs, bots, lice, flies
• Cydectin is a pour on for cattle, Quest is an oral gel for
horses
ANTINEMATODALS
• Piperazine
– Only effective against roundworms
– Partially or fully paralyzes the worm but does not kill it.
– Worms are sometimes passed a mass wiggling in the stool
– Tablets used in small animals, birds, and snakes
– Often found in once a month OTC dewormers
– Very safe
– PIPA-TABS
ANTICESTODALS
• Cause loss of intracellular calcium in the parasite, which leads to
paralysis. Also, the tapeworm’s outer layer becomes permeable
allowing antigens to leak out and the host to produce antibodies.
• Epsiprantel
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CESTEX
Oral tablet for dogs and cats
Does not treat Echinococcus
Causes worm to disintegrate. Proglottids will not be seen in feces after
administration. Not ovicidal.
ANTICESTODALS
• Praziquantel
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Injectable and tablets for dogs and cats
DRONCIT
Treats Dipylidium, Taenia, and Echinococcus
Causes worm to disintegrate. Proglottids will not be seen in feces after
administration. Not ovicidal.
• Remember that flea prevention must be administered when treating Dipylidium
• Combined with pyrantel pamoate in DRONTAL (add Febantel for DRONTAL
PLUS)
ANTITREMATODALS
• Clorsulon is used in cattle for liver flukes
– CURATREM
• Albendazole is used in cattle for liver flukes
– VALBAZEN
• Praziquantel is used for lung flukes in small animals
– DRONCIT
ANTIPROTOZOALS
• Treat Coccidia, Giardia, and Sarcocystis neurona (EPM)
• Amprolium
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Calves and birds
Causes thiamin deficiency in parasite
Treats coccidia
CORID
• Sulfadimethoxine
• An antimicrobial that also treats coccidia in small animals
• ALBON
ANTIPROTOZOALS
• Metronidazole
• Antibacterial and anti-inflammatory that treats Giardia
• High doses may cause neurological signs
• FLAGYL
• Fenbendazole
• Benzimidazole that treats Giardia
• PANACUR
• Ponazuril
• Treats Sarcocystis neurona and coccidia in horses
• MARQUIS
ADULTICIDE
• Melarsomine Dihydrochloride
• Kills adult Dirofilaria immitis
• Arsenic intramuscular lumbar injectable drug for dogs
• IMMITICIDE
• Injection site is commonly painful; many veterinarians provide pain-relieving medications
• Nodules may develop at injection sites
• Exercise restriction is imperative (dying worms live in pulmonary arteries)
• Worms will degenerate and cause inflammation in the lungs (steroids are often given for
this)
• Adulticide is not administered to cats
HEARTWORM PREVENTION
• Selamectin
• REVOLUTION for dogs and cats
• Monthly topical medication.
• Also treats fleas (insecticidal), ear mites, sarcoptic
mange (dogs), hookworms/roundworms (cats), and
Dermacentor tick in dogs
• Milbemycin oxime
• INTERCEPTOR for cats and dogs
• Oral tablet given monthly
• Also treats hookworms, roundworms, and whipworms
(dogs)
• Note: milbemycin is also an otic medication to treat
Otodectes in cats
HEARTWORM PREVENTION
o Milbemycin oxime + lufenuron
• SENTINEL for dogs
• Oral tablet given monthly
• Also treats hookworms, roundworms, whipworms, and fleas
• SENTINEL SPECTRUM = milbemycin oxime + lufenuron + praziquantel for added
tapeworm protection
• Ivermectin
• HEARTGARD for cats and dogs
• Monthly oral medication (tablet or chewable)
• Cat med controls hookworms
• Dose is safe for collies
• Ivermectin + pyrantel pamoate= HEARTGARD PLUS (also controls hookworms and
HEARTWORM PREVENTION
• Moxidectin
• PROHEART 6
• Injectable 6 month preventative for dogs
• Also controls hookworms
• Milbemycin oxime + spinosad
• TRIFEXIS
• Monthly oral tablet for dogs
• Also controls fleas, hookworms, roundworms, and whipworms
DRUGS THAT TREAT ECTOPARASITES
• Fipronil
– FRONTLINE SPRAY and FRONTLINE TOP SPOT
– Topical solution for adult flea control
– Monthly application in dogs and cats
– Fipronil + methoprene = FRONTLINE PLUS (fleas and ticks).
Methoprene is an IGR
– All are OTC
– Blocks GABA receptors, decreases chloride in neuron, hyperexcitability
kills parasite.
DRUGS THAT TREAT ECTOPARASITES
• Imidacloprid
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ADVANTAGE
Topical solution for flea control. Kills adults on contact.
Monthly application in dogs and cats
Blocks acetylcholine receptors
Imidacloprid + pyriproxyfen = ADVANTAGE II (flea control for dogs
and cats. Lice also for dogs). Pyriproxyfen is an IGR.
• Imidacloprid + pyriproxyfen + permethrin = K9 ADVANTIX II (fleas,
ticks, lice and mosquito/fly repellant for dogs) NO CATS
• Imidacloprid + moxidectin = ADVANTAGE MULTI (fleas,
roundworms, hookworms, ear mites, and heartworm preventative
for cats….. Fleas, roundworms, hookworms, whipworms, sarcoptic
mange, and heartworm preventative for dogs)
• Advantage Multi is Rx
DRUGS THAT TREAT ECTOPARASITES
• Nitenpyram
• CAPSTAR
• Oral tablet for flea control in dogs and cats
• Stimulates acetylcholine receptors causing increased nervous system
activity (flea seizures, paralysis, and then death)
• Give as needed (can be daily). Kills adult fleas within 30 minutes of
administration. Animal may begin to scratch.
• Give with an IGR or IDI for maximum flea control.
• OTC
DRUGS THAT TREAT ECTOPARASITES
o Lufenuron
– PROGRAM
– Oral tablet for flea control in dogs and cats
– An IDI that interferes with chitin development (fleas exoskeleton). Does not kill adult fleas.
Will have to wait two weeks before seeing improvement in flea infestation. Give with Capstar.
– Given once monthly. Cat’s dose is higher than dogs.
– 6 month Injectable and monthly oral solution available for cats (dogs have local reaction)
– Lufenuron + milbemycin= SENTINEL (flea control, heartworm preventative, hookworms,
roundworm, and whipworms control in dogs)
– Distributed to all of the animal’s tissues once administered. Stored there and then redistributed
into circulation over time.
– All are Rx
• Metaflumizone
– PROMERIS - Discontinued: linked to causing pemphigus
IGRs, IDIs, JMHs
• IGR: insect growth regulator. Affect immature stages of insects, preventing them from
maturing. No adulticidal activity.
• IDI: insect development inhibitor (a type of IGR) also called a chitin synthesis inhibitor
• JMH: juvenile hormone mimics (a type of IGR)
• Products are distributed over an animal's skin and work by direct contact with the flea. Adult
females absorb the drug and incorporate the IGR into the flea eggs. The eggs may hatch but the
larvae won’t these products should be used with an adulticide.
• Lufenuron (Program) is an IDI that is ingested into flea when it feeds on an animal. Affects
the flea’s ability to produce chitin which is located within the egg and the larvae’s
exoskeleton. Therefore, Lufenuron won‘t kill adult fleas and it can take a couple weeks to
see results. For this reason, Nitenpyram is usually given in the meantime.
• Pyriproxyfen (Nylar) is a JHM, which mimics juvenile hormone that is produced by the
insect’s brain. When the insect’s body detects high levels of JH or a JHM, it fails to fully
mature to the stage of egg production.
DRUGS THAT TREAT ECTOPARASITES
• Selamectin
– REVOLUTION
– Topical solution for flea control, heartworm prevention, ear mite treatment in dogs and
cats (also treats hookworms and roundworms in cats)
– Monthly application
– Not technically an IGR, but does have some ovicidal effects
– Rx
• Spinosad
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COMFORTIS
Oral tablet for flea prevention. Kills adults.
Given monthly to dogs and cats
Spinosad + milbemycin = TRIFEXIS (for dogs: controls fleas, hookworms, roundworms,
whipworms, and is a heartworm preventative)
– Both are Rx
DRUGS THAT TREAT ECTOPARASITES
• Pyrethrins
• Extract of chrysanthemums used in many insecticides.
• Synthetic pyrethroids have a better killing effect than natural ones.
Most pyrethroids end in “thrin” (ex: PERMETHRIN).
• Cause excessive amounts of sodium in the neuron, overstimulating
it. Parasites will suffer seizures and paralysis.
• Highly toxic to cats, causes seizures and hypersalivation. Permethrin
is used in a lot of products to repel ticks and people mistakenly
apply it to cats. Rinse product off!
• Fish are also hypersensitive to toxicity, use with care around water.
DRUGS THAT TREAT ECTOPARASITES
• Formamidines
•Amitraz is the most commonly used
• Decreases release of norepinephrine, causing sedation.
Don‘t use with other MAO inhibitors
•MITABAN for demodex treatment in dogs (also kills ticks)
• Wear gloves when applying dip! May cause transient
sedation for up to 72 hours, hypothermia (drip dry), and
pruritus
•Use caution with collars (PREVENTIC). If lost, monitor for signs of
ingestion.
•TAKTIC for treatment of lice, mange, and ticks on large animals
•Can be reversed with yohimbine, tolazoline, and atipamezole
INSECT REPELLENTS
• Commonly used in human, large, and small animal products.
• Repel gnats, mosquitoes, and flies. When pyrethrins/pyrethroids are added, fleas and ticks
are repelled.
• Sprays, tags, and topicals applied to ear tips
• Used on horses and cattle to prevent flies from laying eggs on the skin (leading to bots and
warbles)
• Used on dogs with upright ears to prevent fly strike.
• Butoxypolypropylene glycol (BUTOX PPG)
• Diethyltoluamide (DEET) is often used in human products for insect repelling. Caused death in
small animals.