Antiparasitics: Effective Solutions for Animal Parasites

1. AntiparasiticsCh 12

2. 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.

3. 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.

4. 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.

5. 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

6. 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)

7. 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)

8. 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.

9. ANTINEMATODALS • pyrantelpamoate • Tetrahydropyrimidine • NEMEX, STRONGID • Considered to be very safe • Often found in feed stores • Ineffective against whipworms • febantel and levamisole • Imidathiazoles • Effective against whipworms

10. 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)

11. ANTINEMATODALS • AVERMECTINS • 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

12. ANTINEMATODALS • selamectin (small 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

13. ANTINEMATODALS • eprinomectin (large animals) • 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

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

15. 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

16. 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.

17. 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

18. ANTITREMATODALS • clorsulonis used in cattle for liver flukes • CURATREM • albendazoleis used in cattle for liver flukes • VALBAZEN • praziquantelis used for lung flukes in small animals • DRONCIT

19. ANTIPROTOZOALS • Treat Coccidia, Giardia, and Sarcocystisneurona (EPM) • amprolium • Causes thiamin deficiency in parasite • Treats coccidia • CORID • sulfadimethoxine • An antimicrobial that also treats coccidia • ALBON

20. ANTIPROTOZOALS • metronidazole • Antibacterial and anti-diarrheal that treats Giardia • High doses may cause neurological signs • FLAGYL • fenbendazole • Benzimidazole that treats Giardia • PANACUR • ponazuril • Treats Sarcocystisneurona and coccidia in horses • MARQUIS

21. ADULTICIDE • melarsominedihydrochloride • Kills adult Dirofilariaimmitis • 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

22. ADULTICIDE • melarsominedihydrochloride • 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

23. 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.

24. 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.

25. 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.

26. 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.

27. DRUGS THAT TREAT ECTOPARASITES • formamidines • Amitraz is the most commonly used • MITABANfor 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

28. 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. • butoxypolypropyleneglycol (BUTOX PPG) • diethyltoluamide(DEET) is often used in human products for insect repelling. Caused death in small animals.