Antiparasitics Ch 12

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). Are a quickly changing market.

THE IDEAL ANTIPARASITIC IS.. Selectively toxic to the parasite and not the host. Does not induce resistance in the target parasite. 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 _______ parasites cause infections and live inside the body. _______ parasites cause infestations and live outside the body. Parasites in an abnormal location in a hosts’ body are ___________. Anthelmintics: kill helminth worms (parasitic worms) Antinematodals: treat round worms Anticestodals: treat tapeworms Antitrematodals: treat flukes Antiprotozoals: treat single-celled organisms: Coccidia, Giardia, Toxoplasma Drench vs. Pour-on TERMS

ANTINEMATODALS BENZIMIDAZOLES In addition to nematodes, some products can treat some flukes, cestodes, and protozoa Ysed in large animals, small animals, and exotics Usually have to apply more than one dose consecutively “bendazole” suffix thiabendazole (EQUIZOLE, TBZ, OMNIZOLE) fenbendazole (PANACUR/SAFEGUARD) oxibendazole (ANTHELCIDE EQ) albendazole (VALBAZEN) 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”). Not used as often with animals as they used to be. Also used as pesticides. Examples: coumaphos (BAYMIX), dichlorvos (TASK) ANTINEMATODALS

ORGANOPHOSPHATES and CARBAMATES 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

ANTINEMATODALS pyrantel pamoate febantel and levamisole Tetrahydropyrimidine NEMEX, STRONGID Considered to be very safe Often found in feed stores Ineffective against whipworms febantel and levamisole Imidathiazoles Effective against whipworms

ANTINEMATODALS MACROLIDES: Avermectins and Milbemycin Structurally similar with a macrocyclic ring that are derived for a Streptomyces bacterium. Cause paralysis and death of nematodes. Among the safest compounds to use (these receptors are located behind the blood-brain barrier within the CNS in mammals)

ANTINEMATODALS AVERMECTINS ivermectin (many species) Suffix –ectin ivermectin, selamectin, doramectin, eprinomectin, moxidectin ivermectin (many species) 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 _____________________, a protein that moves drugs from the blood brain barrier cells back into the blood Toxicity causes neurological signs Heartgard doses are safe No antidote

ANTINEMATODALS selamectin (small animals) doramectin (large animals) REVOLUTION Heartworm preventation, internal parasites, flea control, ear mites, sarcoptic mange (dogs), ticks (dogs) Topical doramectin (large animals) DECTOMAX Internal worms, grubs, lice, mange Injectable and pour-on ANTINEMATODALS

ANTINEMATODALS eprinomectin (large animals) moxidectin (many species) EPRINEX Internal worms, grubs, lice, mange Pour-on moxidectin (many species) QUEST, CYDECTIN, PROHEART 6 Nematodes, mites, grubs, bots, lice, flies Paste, Pour-on, Injectable

ANTINEMATODALS MILBEMYCIN milbemycin oxime (small animals) INTERCEPTOR, SENTINEL Heartworm preventative, hookworms, roundworms, ear mites, mange Oral tablet for dogs and cats

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 Used in many species Often used in OTC dewormers

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 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 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. DRONTAL- praziquantel, pyrantel pamoate DRONTAL PLUS – praziquantel, pyrantel pamoate, febantel

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 Causes thiamin deficiency in parasite Treats coccidia CORID sulfadimethoxine An antimicrobial that also treats coccidia ALBON

ANTIPROTOZOALS metronidazole fenbendazole ponazuril Antibacterial and anti-diarrheal 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

ADULTICIDE melarsomine dihydrochloride 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

Please reference provided chart for all current medications on treating endo and ectoparasites in small animals. This chart is based off of the current CAPC recommendations. Please reference CAPC regularly to stay current on these medications as they change frequently.

IGRs 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 JHM: juvenile hormone mimic (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. These products should be used with an adulticide.

IGRs, IDIs, JMHs Lufenuron 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. Pyriproxyfen 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 pyrethrins Extract of chrysanthemums used in many insecticides. Most end in “thrin” (ex: PERMETHRIN). 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 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 Effects an be reversed with yohimbine, tolazoline, and atipamezole

INSECT REPELLENTS 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.