Fundamentals of Pharmacology for Veterinary Technicians Chapter 15

Helminths Nematodes Platyhelminths Cestodes Trematodes Figure 15-1

Figure 15-2

Figure 15-3

Figure 15-4

Figure 15-5

Table 15-1 Helminths of Veterinary Significance Main Category Nematodes Location of Parasite Abomasal worms in ruminants or stomach worms in monogastric animals Scientific and Common Names Barberpole worm Haemonchus (R) Brown stomach worm Ostertagia ostertagi (R) Small stomach worm or hairworm Trichostrongylus axei (R, H) Hyostrongylus rubidus (Sw) Large-mouth stomach worm Habronema muscae (H) (Continued) Table 15-1

Table 15-1 (Continued ) Main Category Cestodes (tapeworms) Trematodes (flukes) Location of Parasite Scientific and Common Names Intestinal worms Small intestinal worms Cooperia (R) Hookworms Bunostomum phlebotomum (R), Ancylostoma sp (D, F) Nodular worms Oesophagostomum spp. ( R, Sw) Thread-necked intestinal worm Nematodirus helvetianus (R) Bankrupt worm Trichostrongylus colubriformis (R) Large strongyles Strongylus Circulatory system worms Triodon- tophorus spp. (R, E) Small strongyles Cyathostomum spp., Cylicocyclus spp., Cylicostephanus spp., Cylicodontophorus spp. (R) Whipworms Trichuris suis (Sw), Trichuris vulpis (D) Threadworms Strongyloides ransomi (Sw), Strongyloides westeri (E), Strongyloides stercoralis (D) Ascarids Parascaris equorum (H), Toxocara canis (D), Toxocara cati (F), Toxascaris leonina (D, F) Pinworms Oxyuris equi (E) Heartworms Dirofilaria immitis (D, F) Lungworms Dictyocaulus spp. (R, H) Prostostrongylus rufescens (S, G) Muellerius capillaris (S, G) Metastrongylus spp. (Sw) Filaroides spp. (D) Kidney worms Stephanurus dentatus (Sw) Urinary bladder worm Gastrointestinal worms Capillaria spp. (D, F) Habronema spp. (H) Draschia spp. (H) Skin worm Onchocerca spp. (H) Liver fluke Deer liver fluke Lung fluke Moniezia benedeni (R) Taenia spp. (R, D, F) Echinococcus granulosus (R is intermediate host, D) Dipylidium caninum (D, F) Anoplocephala perfoliata, A. magna (H) Paranoplocephala mamillana (H) Fasciola hepatica (R) Fascioloides magna (R) Paragonimus kellicotti (D, F) R = ruminants, C = cattle, S = sheep, G = goats, Sw = swine, D = dogs, F = cats, H = horses Table 15-1 continued

Table 15-2 Protozoa of Veterinary Significance Type of Movement Location of Parasite Scientific and Common Names None Gastrointestinal tract Coccidia Eimeria spp. (R, Sw, H) None Gastrointestinal tract Coccidia Isospora spp. (Sw, D, F) None Gastrointestinal tract; muscle tissue Toxoplasma gondii (F) Flagellum Gastrointestinal tract Giardia spp. (R, H, D, F) None Gastrointestinal tract Cryptosporidium spp. (R, H, D, F, Sw) None Muscle in ruminants Sarcocystis spp. (R in muscle) Gastrointestinal tract in dogs and cats Sarcocystis shed in stool) Central nervous system Sarcocystis neurona (H) F lagellum Reproductive tract Tritrichomonas foetus (C) None Circulatory system Babesia (C, H, D) None Circulatory system Cytauxzoon felis (F) Flagellum Circulatory system Trypanosoma (D, C) Cilia Gastrointestinal tract Balantidium coli (Sw) R = ruminants, C = cattle, S = sheep, G = goats, Sw = swine, D = dogs, F = cats, H = horses Table 15-2

Strongid C 2X Fundamentals of Pharmacology for Veterinary Technicians Chapter 15 Table 15-3 Administration Routes for Anthelmintics Main Route Example Route Description Concerns Oral Tablets May be hard tablet, chewable tablet, or bolus (large pill) that animal ingests or is given Levasole (levamisole hydrochloride) Cattle Wormer Boluses Allows greater control given Palatability is important (especially with cats and horses) FOR ORAL USE IN CATTLE NET CONTENTS: 50 BOLUSES Liquid May be in the form of a solution, suspension paste, paste syringe, or drench ivomec Eprinex Drug must be shaken well to ensure adequate mixing of chemical throughout the liquid Paste syringes contain a precalibrated amount of paste that need not be shaken Drenches are liquid forms given by mouth that force the animal to drink Allows greater control over amount of drug given Feed additives May be in feed, added to mineral mixes, added to drinking water, or added to salt blocks Treats parasites in large numbers of animals Allows little control over amount of drug ingested by an individual animal Is stress free for the animals Saves expense of rounding up livestock Strongid C 2X (Continued) Table 15-3

Main Route Example Route Description Concerns Sustainedrelease Device is implanted in rumen to allow slow release of the drug over time (especially helpful in treating later stages of parasite larvae) Saves time in retreating of animals Can treat animals over a period (like the complete grazing season) SR Bolus Injectable Solution Given SQ usually (if given IM, may affect the carcass) CYDECTIN CYDECTIN Easy way to administer Local reaction is possible, but Allows greater control over amount of drug given Achieves higher blood levels rapidly Requires livestock to run through chutes or be crowded into restricted spaces for injection with multidose syringes for treatment Can control amount of drug given Topical (pour-ons) Solution ECTOMETHRIN Absorbed through the skin via the sebaceous glands and hair follicles Used in large animals Achieves high blood levels rapidly Easy to administer Reduces stress for treated animals Used for internal and external parasites Pour-ons are highly ECTOMETHRIN Table 15-3 continued

Table 15-4 Types of Antiparasitic Drugs Benzimidazoles (nematodes) thiabendazole oxibendazole mebendazole (also works on tapeworms) fenbendazole (also works on tapeworms, flukes, and Giardia protozoa) albendazole (also works on tapeworms, flukes, and Giardia protozoa) oxfendazole (also works on tapeworms and flukes) febantel (a probenzimidazole used in combination with other products to broaden its spectrum of activity) Imidazothiazoles (nematodes) levamisole Tetrahydropyrimidines (nematodes) pyrantel pamoate pyrantel tartrate morantel tartrate Organophosphates (nematodes; ectoparasites, including bots) dichlorvos coumaphos Piperazines (nematodes) piperazine Avermectins (also called macrocyclic lactones) (nematodes; heartworm prevention; ectoparasites, such as bots and grubs) ivermectin eprinomectin selamectin moxidectin milbemycin oxine doramectin Depsipeptides (nematodes) emodepside (used in combination with praziquantel) Pyrazine derivatives (platyhelminths) praziquantel (tapeworms, flukes) epsiprantel (tapeworms) Benzene sulfonamide (flukes) clorsulon Coccidiostats (coccidia) sulfadimethoxine nicarbazine Nitroimidazoles (Giardia) metronidazole Carbanilide derivative (Babesia) imidocarb Aminoquinolone (Babesia) primaquine amprolium monensin Folic acid antagonist (Toxoplasma and Sarcocystis) pyrimethamine Triazine (Sarcocytis) ponazuril Nitrothiazolyl-salicylamide derivative (Sarcocystis) nitazoxanide decoquinate robenidine Table 15-4

Table 15-5 Application Methods for Ectoparasiticides Type of Product Prediluted sprays (include sprays for animals and premise sprays) Advantages Convenient and easy to use (apply from head to tail, avoiding eyes, mouth, and nose) Usually has quick kill May have residual effects Available for animal and environment Concentrated Sprays Concentrated form may offer cost savings Can be diluted at different concentrations for different ectoparasites Yard spray/kennel spray Dips Offer residual effects Offer residual effects Pour-ons Can ensure that an individual animal is treated May treat many animals at a time with proper application devices Shampoos Rinse well May contain medication effective against parasites Disadvantages Water-based sprays do not penetrate oily coats or fabrics well Alcohol-based sprays may be drying and irritating to skin Error in dilution may occur Diluted product may not have long shelf life Can only be used Efficacy varies on environment Must be diluted properly Animal should be shampooed first Animal must dry with dip product on cannot rinse product off Activity of drug may be limited if applied to unclean animal (e.g., animal with caked mud or manure on its hide) May be applied incorrectly, resulting in limited value of the treatment or development of toxicity (application varies; may be along the backline from shoulders to the pelvis or in single spot) May only contain products for cleaning the coat No residual effect even if medication present May have to be diluted before use Must leave on animal for a specified time prior to rinsing (Continued) Table 15-5

Type of Product Advantages Dusts or powders Can be used in animals that do not tolerate sprays Foggers Work well in large, open rooms Quick method for environmental control Oral products No mess Works for a period of time Topical long-acting (Spot-ons) Long-lasting May work for multiple parasites May work for different stages of parasite development Work by providing area of repellent near application site Injectables Long-lasting in some cases Easier for owners who do not want to administer medication to the animals themselves Disadvantages Do not provide quick kill May irritate and dry skin Product does not get everywhere needed (in corners or furniture); however, coverage can be improved if premise spray is used with the fogger Can be toxic to fish; must cover food products when applying May not kill all stages of the ectoparasite May have systemic effects Ectoparasite may have to take a effective May cause skin problem at site of application Causes oiliness at site of application Animal should avoid bathing or swimming with some products May not be usable on young, old, or sick animals May cause adverse reaction at injection site Should be given by veterinary staff Table 15-5 continued

Table 15-6 Chemical Products for Ectoparasite Control Product Category Pyrethrins and pyrethroids: Names end in -rin or -thrin Pyrethrins are natural plant products Pyrethroids are synthetic pyrethrins Insect growth regulators (IGR): Include insect development inhibitors and juvenile hormone mimics Generic and Trade pyrethrin (Mycodex Shampoo, Bio Spot Shampoo ) d-trans allethrin (Duocide Spray ) permethrin (ProTICall ) methoprene (Ovitrol and Siphotrol ) pyriproxyfen (Nylar, Vectra TM ) Very safe Quick kill Adulticide, insecticide/miticide Often manufactured with other products such as imidacloprid and pyriproxyfen Acts on the parasite s nerve cell membrane to disrupt the sodium channel current, which delays repolarization and paralyzes the parsite May have limited residual effects Form labeled for dogs may be too high a concentration for cats In small animals used primarily for fleas and ticks in dogs In large animals used primarily for flies, lice, mites, mosquitoes, ticks, and keds Commonly used in sprays, dips, foggers, pour-ons, insecticidal ear tags, and premise sprays Products with IGR provide the flea with high levels of IGR, which mimics the insect s juvenile hormone (JH). Fleas need low levels of JH to molt to the next stage; high levels interrupt normal molting, so the insect stays in the larval stage and eventually dies When combined with an adulticide (permethrin, fipronil, phenothrin, etc.), it kills all stages of the parasite, making reinfestation unlikely Do not have adulticide activity by themselves Found in sprays and flea collars (Continued) Table 15-6

Product Category Generic and Trade Chitin synthesis inhibitor lufenuron (Program ) lufenuron and milbemycin (Sentinel ) lufenuron and nitenpyram (Capstar Flea Management System, Program Flavor Tabs) Neonicotinoid nitenpyram (Capstar ) nitenpyram and lufenuron (Capstar Flea Management System, Program Flavor Tabs) Chitin is an insect protein that gives strength and stiffness to its body; chitin synthesis inhibitors prevent proper formation of this protein Lufenuron is an oral tablet given to dogs and a suspension or tablet given orally or an injection given SQ to cats to protect against fleas for 1 month Fleas that feed on blood containing lufenuron continue to lay eggs, but the eggs fail to develop normally Does not kill adult fleas Neonicotinoid compound that binds and inhibits nicotinic acetylcholine receptors Tablet that kills adult fleas within against eggs or immature forms if used alone) Can safely give a dose as often as one per day Can use on puppies and kittens older than four weeks and weighing more than dinotefuran and pyriproxyfen (Vectra TM for Cats, Vectra TM for Cats and Kittens) Synergists piperonyl butoxide (Ecto-foam, Adams Flea & Tick Dust II ) N-octyl bicycloheptene dicarboximide (Ectokyl 3X Flea & Tick Shampoo, Pyrethrin Plus Shampoo ) Third-generation neonicotinoid (dinotefuran) and IGR (pyriproxyfen) that can be used on kittens older than eight weeks of age Once-monthly topical spot-on that kills adult fleas within six hours and controls the development of all flea stages Have limited activity against arthropods; (some inhibit insect metabolic enzymes); however, they increase the efficacy of pyrethrins and pyrethroids Found in sprays, shampoos, dusts, and dips Imidacloprid imidacloprid (Advantage ) Acts as an insect neurotoxin by binding to the niconyl receptor (inhibits cholinergic activity of the parasite) Marketed for dogs and cats Applied topically at the back of the neck, but is not absorbed into the blood Kills adult fleas on contact Has four-week residual effect imidacloprid and permethrin (K9 Advantix ) Works synergistically to rapidly paralyze and kill parasites Kills fleas (adult and larval stages) and kills and repels mosquitoes, and ticks (deer, American dog, Brown dog, lone star) For use on dogs and puppies seven weeks of age or older Not for use on cats (Continued) Table 15-6 continued

Table 15-6 (Continued ) Product Category Generic and Trade imidacloprid and moxidectin (Advantage Multi for Dogs, Advantage Multi for Cats) Phenylpyrazole fipronil (Frontline ) fipronil with methoprene (Frontline Plus ) Semicarbazone metaflumizone (ProMeris for Cats) metaflumizone plus amitraz (ProMeris Duo for Dogs) Kills adult fleas, adult and immature hookworms, adult roundworms, adult whipworms, and prevents heartworm disease in dogs over seven weeks of age Kills adult fleas, ear mites, adult and immature hookworms, adult roundworms, and prevents heartworm disease in cats over nine weeks of age Once-monthly topical solution Fipronil interferes with chloride channels of insects, which overstimulates their nervous system causing death of adult fleas, ticks, and chewing lice (Figure 15-5) Methoprene is an insect growth regulator, which makes the combination product effective against flea eggs and flea larvae Is applied topically, but is not absorbed into the blood Collects in the oils of the skin and hair follicles and continues to be released over a period of time resulting in residual activity (spreads over the body in 24 hours) Kills newly emerged adult fleas before they can lay eggs Residual activity even after bathing Labeled for treatment of fleas, ticks, and chewing lice when used monthly and control of sarcoptic mange with repeated treatments Not for use in puppies or kittens less than eight weeks of age Blocks sodium influx, which is needed to propagate a nerve impulse in fleas that causes a reduction in feeding, paralysis, and death of adult fleas Once-monthly topical spot-on labeled for use in cats greater than eight weeks of age for treatment and prevention of fleas Hypersalivation may be seen if cat licks application site Combination product with amitraz is a topical spot-on for control and prevention of adult fleas and ticks (Ixodes ricinus, Ixodes hexagonus, Dermacentor reticulates, Dermacentor variabilis, and Rhipicephalus sanguineus) in dogs over eight weeks of age; extra-label use for demodectic and sarcoptic mange mites Hypersalivation may be seen if dog licks application site (Continued) Table 15-6 continued

Product Category Generic and Trade Avermectin selamectin (Revolution ) Interferes with postsynaptic stimulation of the muscle fiber in arthropods or neurons in nematodes causing paralysis and death In cats works on adult fleas and eggs, heartworms, ear mites, hookworm, and roundworms In dogs works on adult fleas and eggs, heartworms, ear mites, sarcoptic mange, and American dog tick Acetylcholine receptor agonist ivermectin (Ivomec, Equell paste, Equimax, Eqvalan ) Injectable or oral solution used for some ectoparasites and endoparasites Potentiates insect s GABA neural and neuromuscular transmission Blood-feeding ectoparasites (such as fleas, mites, and lice) are killed much better with ivermectin than superficial, nonblood feeders (like Cheyletiella spp.) Effective against the following ectoparasites: bots, grubs, lice, and mites (including demodex) doramectin (Dectomax ) Injectable and topical solution used for some ecto- and endoparasites. Used as a pour-on in cattle for biting lice and mites; used in dogs and cats for generalized demodicosis eprinomectin (Ivomec, Eprinex ) Topical pour-on for beef and dairy cattle Used to treat and control GI nematodes and ectoparasites (cattle grubs, lice, mange mites, and horn flies), ear mites (Psorpotes cuniculi) in rabbits Increases permeability of the cell parasite s membrane to chloride ions resulting in paralysis and death of the parasite. No milk or meat withdrawal spinosad (Comfortis ) One-month oral chewable flea protection for treatment and prevention of fleas in dogs 14 weeks of age or older Causes involuntary muscle contractions in fleas that leads to seizures, paralysis, and death Fast acting and long acting Flea death begins in 30 minutes and is complete in four hours May cause systemic side effects such as vomiting, anorexia, lethargy, or diarrhea Administration with food increases its effectiveness (Continued) Table 15-6 continued

Table 15-6 (Continued ) Product Category Generic and Trade Formamidines amitraz (Mitaban Dip, PrevenTIC Collar, ProMeris for dogs, Taktic EC) Sulfurated lime solution lime sulfur (Lym Dyp, LimePlus Dip ) Repellents DEET (Blockade ) butoxypolypropylene glycol (VIP Fly Repellent Ointment) Used for treatment of demodectic mange and scabies in dogs; ticks, mange mites, and lice in beef and dairy cattle and swine (there is a withdrawal time in swine) Alpha-2 agonist and monoamine oxidase inhibitor that causes excess adrenergic activity in the parasite s nervous system Animals may show sedation for 24 72 hours following treatment Toxic to cats and rabbits (although has been used on cats in diluted form) Use gloves and protective clothing when applying to animals; wash hands and arms after application to animal Use in well-ventilated area Flammable until diluted with water Yohimbine and atipamezole are antagonists of amitraz Provides antimicrobial and antiparasitic activity through the formation of pentathionic acid and hydrogen sulfide after application Used in the treatment of sarcoptic and notoedric mange, cheyletiellosis, chiggers, fur mites, and lice; also demodicosis in cats Also effective for the treatment of ringworm May stain light-colored animals Used as a rinse or dip following dilution Used to repel mosquitoes, flies, and gnats May be used in combination with pyrethrins and pyrethroids Include sprays, ear tags, and topicals for ear tips Rotenone rotenone (generic) Uncouples oxidative phosphorylation Used in dips and pour-on liquids Toxic to fish; consider pesticide runoff possibilities if rotenone is used to treat insects on plants Not commonly used due to the availability of safer chemicals D-limonene D-limonene (VIP Flea Dip and Shampoo ) Extract of citrus peel that has some insecticidal activity Provides quick kill No residual Pleasant smell Used with other products Table 15-6 continued

Table 15-7 Drugs for Monthly (or Longer) Prevention of Fleas, Ticks, and Heartworm Disease Effective for Fleas dinotefuran and pyriproxyfen (Vectra TM for Cats, Vectra TM for Cats and Kittens) dinotefuran, pyriproxyfen, and permethrin (Vectra TM 3D) fipronil (Frontline ) fipronil with methoprene (Frontline Plus ) imidacloprid (Advantage ) imidacloprid and moxidectin (Advantage Multi for dogs) imidacloprid and permethrin, Proticall ) lufenuron (Program ) metaflumizone (ProMeris for Cats) metaflumizone plus amitraz (ProMeris Duo for Dogs) nitenpyram (Capstar ) nitenpyram and lufenuron (Capstar Flea Management System, Program Flavor Tabs) permethrin (ProTICall ) selamectin (Revolution ) spinosad (Comfortis ) Effective for Ticks amitraz(preventic collar) fipronil (Frontline ) fipronil with methoprene (Frontline Plus ) permethrin (ProTICall ) selamectin (Revolution ) (labeled for American dog tick only) Effective for Prevention of Heartworm Disease ivermectin (Heartgard, Heartgard Plus, Tri-Heart Plus, and Iverhart Plus) (Plus products also work on some intestinal parasites) milbemycin (Interceptor, Sentinel [also works on some intestinal parasites]) moxidectin (ProHeart -6 works for six months) selamectin (Revolution ) (also works on ear mites) Table 15-7

Table 15-8 Internal Parasite Drugs Parasite Category Antinematodal Anticestodals Antitrematodals Drug Category and Examples Benzimidazoles oxibendazole (Anthelcide EQ Equine Wormer Paste ) mebendazole (Telmintic ) fenbendazole (Panacur ) albendazole (Valbazen ) oxfendazole (Benzelmin Paste and Synanthic ) febantel (Drontal Plus also contains pyrantel pamoate and praziquantel combination) Imidazothiazoles levamisole (Levasole and Tramisol ) Tetrahydropyrimidines pyrantel pamoate (Nemex and Strongid-T ) pyrantel tartrate (Strongid-C ) morantel tartrate (Rumatel ) Piperazines piperazine (Pipa-Tabs and Hartz Advanced Care Once-a-Month Wormer for Puppies) Avermectins or macrocyclic lactones ivermectin (Heartgard, Heartgard Plus, Ivomec ) eprinomectin (Ivomec, Eprinex ) selamectin (Revolution ) moxidectin (ProHeart-6, Cydectin, Quest 2% Equine Oral Gel) milbemycin oxine (Interceptor, Sentinel ) doramectin (Dectomax ) Depsipeptides emodepside (Profender, which also contains praziquantel) Pyrazine derivatives praziquantel (Droncit, Profender [which also contains emodepside], and Quest Plus [which also contains moxidectin]) epsiprantel (Cestex ) Benzimidazoles albendazole (Valbazen ) mebendazole (Telmintic ) fenbendazole (Panacur ) oxfendazole (Benzelmin Paste and Synanthic ) Benzene sulfonamide clorsulon (Curatrem, Ivomec Plus, which also contains ivermectin) Benzimidazoles albendazole (Valbazen ) fenbendazole (Panacur ) oxfendazole (Benzelmin Paste and Synanthic ) Pyrazine derivative praziquantel (Droncit, Profender [which also contains emodepside], and Quest Plus [which also contains moxidectin]) (Continued) Table 15-8

Table 15-8 (Continued ) Parasite Category Antiprotozoals Drug Category and Examples Coccidiostats sulfadimethoxine (Albon ) amprolium (Corid ) decoquinate (Deccox ) nicarbazine (Maxiban 72 ) monensin (Coban 60, Rumensin ) robenidine (Robenz Type A Medicated Article ) Nitroimidazoles metronidazole (Flagyl ) Benzimidazoles fenbendazole (Panacur ) albendazole (Valbazen ) Carbanilide derivative imidocarb (Imizol ) Aminoquinoline primaquine (generic) Folic acid antagonist pyrimethamine (Daraprim ) pyrimethamine plus sulfadiazine (ReBalance ) Triazine ponazuril (Marquis ) Nitrothiazolyl-salicylamide derivative nitazoxanide (Navigator ) Table 15-8 continued

Table 15-9 Heartworm Medication Drug Category Examples Adulticide Melarsomine (Immiticide ) Microfilaricides ivermectin (Heartgard, Heartgard Plus, Heartgard for Cats, Iverhart Plus, Tri-Heart Plus) milbemycin (Interceptor, Sentinel ) levamisole (Levasole, Tramisol ) Preventatives ivermectin (Heartgard, Heartgard Plus, Heartgard for Cats, Iverhart Plus, Tri-Heart Plus) milbemycin (Interceptor, Sentinel ) selamectin (Revolution ) moxidectin (ProHeart-6 ) Table 15-9