Antiprotozoan Drugs

42
Antiprotozoan Drugs


Jennifer L. Davis and Jody L. Gookin


Numerous chemotherapeutic agents are known to possess activity against parasitic protozoa (Tables 42.1 and 42.2). Although antiprotozoal activity is characteristic of many different chemical groups, most possess a rather narrow spectrum of activity. This is in contrast to antibacterial agents, which are effective against a wide variety of organisms. This chapter presents the clinically relevant antiprotozoan drugs used against the more important protozoal disease agents of domesticated animals.


Table 42.1 Summary of drugs used to treat selected protozoal diseases in animals










































































































































































































































Protozoaldisease Protozoa Species Drug class Drug and dosing regimen
Giardiasis Giardia duodenalis, G. intestinalis, G. lambia Dogs Nitroimidazoles

Metronidazole: 12–15 mg/kg PO q12h for 8 days


Tinidazole: 15 mg/kg PO q12h




Benzimidazoles

Albendazole: 25 mg/kg q12h for 2 days


Fenbendazole: 50 mg/kg q24h for 3 days


Febantel, pyrantel, and praziquantal: febantel (26.8–35.2 mg/kg), pyrantel (26.8–35.2 mg/kg), praziquantel (5.4–7 mg/kg) PO q24h for 1–3 days



Cats Nitroimidazoles

Metronidazole: 22–25 mg/kg PO q12h for 5–7 days


Tinidazole: 15 mg/kg PO q24h


Secnidazole: 30 mg/kg PO q24h




Benzimidazoles

Fenbendazole: 50 mg/kg q24h for 5 days


Febantel, pyrantel, and praziquantal: febantel (56.5 mg/kg), pyrantel (11.3 mg/kg), and praziquantel (37.8 mg/kg) PO q24h for 5 days



Horses Nitroimidazoles Metronidazole: 5 mg/kg PO q8h for 10 days


Cattle Benzimidazoles

Albendazole: 20 mg/kg PO q24h for 3 days


Fenbendazole: 5–20 mg/kg PO q24h for 3 days




Aminoglycosides Paromomycin: 75 mg/kg PO q24h for 5 days
Trichomoniasis Tritrichomonas foetus, Pentatrichomonas hominis, Trichomonas gallinae Cats Nitroimidazoles

Tinidazole: 30 mg/kg PO q24h for 14 days


Ronidazole: 30 mg/kg PO q24h for 14 days



Cattle Nitroimidazoles Metronidazole: 75 mg/kg IV q12h for 3 dosesa


Pigeons Nitroimidazoles

Metronidazole: 40–60 mg/kg orally once a day for 5 days


Ronidazole: 5 mg/kg orally once a day for 14 days


Carnidazole: 20 mg/kg orally once

Trypanosomiasis Trypanosomas cruzi Dogs Nitroimidazoles Benznidazole: 5–7 mg/kg PO q24h for 2 months



Nitrofurans Nifurtimox: 2–7 mg/kg PO q6h for 3–5 months


Cattle Diamidene derivatives Diminazene diaceturate: 3.5–7 mg/kg IM
Babesiosis Babesia divergens, Dogs Tetracyclines

Doxycycline: 10 mg/kg PO q12h for 11 days (B. canis)


Doxycycline (7–10 mg/kg, q12h) in combination with enrofloxacin (2–2.5 mg/kg, q12h) and metronidazole (5–15 mg/kg, q12h) for a duration of 6 weeks (B. gibsoni)



B. equi, B. caballi, B. bigemini, B. canis Hydroxyquinolones and naphthoquinones Atovaquone: 13.3 mg/kg PO q8h combine with azithromycin 10 mg/kg PO q24h for 10 consecutive days (B. gibsoni)



Diamidene derivatives

Diminazene diaceturate: 3.5–5 mg/kg BW IM (B. canis); 3.5 mg/kg q12h for 2 treatments (B. gibsoni)


Pentamidine isethionate: 16.5 mg/kg IM on 2 consecutive days


Phenamidine isethionate: 15–20 mg/kg SC q24h for 2 days (B. gibsoni); 8–13 mg/kg SC once (B. canis)


Imidocarb dipropionate: 7.5 mg/kg SC (B. canis); 3.5 mg/kg diminazene followed by 6 mg/kg imidocarb on the following day (B. canis)



Horses Tetracyclines Chlortetracycline: 0.5–2.6 mg/kg IV q24h for 6 days (B. equi)



Diamidene derivatives

Diminazene diaceturate: 3–5 mg/kg IM q12h for 2 treatments (B. caballi); 6–12 mg/kg IM (B. equi); 0.5 mg/kg IM (B. bigemina)


Phenamidine isethionate: 8.8 mg/kg IM q12h for 2 treatments


Amicarbalide: 8.8 mg/kg IM q12h for 2 treatments (B. caballi)


Imidocarb dipropionate: 1–2 mg/kg IM q12h for 2 treatments (B. caballi); 4 mg/kg IM q72h for 4 treatments (B. equi)



Cattle Tetracyclines Oxytetracycline: 20 mg/kg IM every 4 days for 3 weeks (B. divergens)



Diamidene derivatives

Diminazene diaceturate: 3–5 mg/kg IM (B. bigemina and B. bovis)


Pentamidine isethionate: 0.5–2 mg/kg SC


Phenamidine isethionate: 8–13 mg/kg IM q12h for 2 treatments


Amicarbalide: 5–10 mg/kg IM


Imidocarb dipropionate: 1–3 mg/kg IM or SC

Cryptosporidiosis Cryptosporidium parvum Cats Aminoglycosides Paromomycin: 165 mg/kg PO q12h for 5 daysb



Nitrothiazole derivatives Nitazoxanide: 75 mg/kg PO once


Cattle Aminoglycosides Paromomycin: 12.5–50 mg/kg PO q24h for 12 days



Azalides Azithromycin: 1500–2000 mg/calf/day PO for 7 days



Nitrothiazole derivatives Nitazoxanide: 1.5 g suspended in water and given orally q12h



Alkaloids Halofuginone: 100 μg/kg BW PO q24h for 7 days


Goats Aminoglycosides Paromomycin: 50 mg/kg PO q12h for 10 days
Leishmaniasis Leishmania donovani, L. infantum, L. chagasi Dogs Pentavalent antimonials

Sodium stibogluconate: 30–50 mg/kg pentavalent antimony IV or SC q24h for 3–4 weeks


Meglumine antimonate: 100 mg/kg IV or SC q24h for 3–6 weeks or 75 mg/kg SC q12h in combination with allopurinol at 15 mg/kg PO q12h


Liposomal meglumine antimonate: 9.8 mg/kg IM or SC q24h

Hepatozoonosis Hepatozoon americanum Dogs Aminoglycosides Paromomycin: 20–40 mg/kg IM q24h for 15–30 days



Hydroxyquinolones and naphthoquinones Decoquinate: feed additive (27.2 grams/pound or 59.8 grams/kg of premix) added to moist dog food at 0.5–1.0 tablespoons per 10 kg BW twice a day



Triazene derivatives Toltrazuril: 5–10 mg/kg PO q12h for 5–10 days



DHFR/TSc inhibitors Trimethoprim–sulfadiazine: 15 mg/kg PO q12h combined with clindamycin 10 mg/kg PO q8h and pyrimethamine 0.25 mg/kg PO q12h for 14 daysd



Diamidene derivatives Imidocarb dipropionate: 5–6 mg/kg BW SQ or IM every 2 weeks until gamonts are no longer present in blood smears
Cytauxzoonosis Cytauxzoon felis Cats Diamidene derivatives Imidocarb dipropionate: 3.5 mg/kg BW IM once then repeat 7 days later



Hydroxyquinolones and naphthoquinones Atovaquone: 15 mg/kg PO q8h combine with azithromycin 10 mg/kg PO q24h for 10 consecutive days
Theileriosis Theileria parva Cattle Hydroxyquinolones and naphthoquinones

Parvaquone: 20 mg/kg IM once


Buparvaquone: 2.5 mg/kg IM 1–2 times




Alkaloids Halofuginone: 1–2 mg/kg PO once
Equine Protozoal Myelitis Sarcocystis neurona Horses Triazene derivatives

Diclazuril: 0.5–1 mg/kg PO q24h for 28 days, or 0.5 mg/kg PO, once every 3–4 days.


Toltrazuril: 5 mg/kg PO q24h for 28 days


Ponazuril: 15 mg/kg PO loading dose; 5 mg/kg PO q24h for 28 days




DHFR/TS inhibitors Pyrimethamine: 1 mg/kg PO q24h combined with sulfadiazine 20–30 mg/kg PO q12h for 30 days after clinical signs plateau




Nitrothiazole derivatives


Hydroxyquinolones and naphthoquinones

Nitazoxanide: 11.36 mg/lb (25 mg/kg) PO q24h for the first 5 days, followed by 22.72 mg/lb PO q24h for 23 days


Decoquinate: 0.5 mg/kg PO q24h combined with levamisole 1 mg/kg PO q24h for 10 days

Neosporosis Neospora caninum Dogs DHFR/TS inhibitors Pyrimethamine: 0.25–0.5 mg/kg PO q12h combined with sulfadiazine 30 mg/kg PO q12h for 2–4 weeks



Lincosamides Clindamycin: 12.5–18.5 mg/kg PO q12h for 2–4 weeks


Cattle Triazene derivatives Ponazuril: 20 mg/kg PO q24h for 6 days
Toxoplasmosis Toxoplasma gondii Dogs DHFR/TS inhibitors Pyrimethamine: 0.25–0.5 mg/kg PO q12h combined with sulfadiazine 30 mg/kg PO q12h for 2–4 weeks



Lincosamides Clindamycin: 3–13 mg/kg PO or IM q8h for 2 weeks or 10–20 mg/kg PO or IM q12h for 2 weeks


Cats DHFR/TS inhibitors Pyrimethamine: 0.25–0.5 mg/kg PO q12h combined with sulfadiazine 30 mg/kg PO q12h for 2–4 weeks



Lincosamides Clindamycin: 10–12 mg/kg PO q12h for 4 weeks or 12.5–25 mg/kg IM q12h for 4 weeks
Sarcocystis Sarcocystis spp. Dogs Hydroxyquinolones and naphthoquinones Decoquinate: 10–20 mg/kg PO q12h
Coccidiosis Eimeria sp., Isospora sp. Dogs DHFR/TS inhibitors

Ormetoprim/sulfadimethoxine: 11 mg/kg ormetoprim combined with 55 mg/kg sulfadimethoxine PO for up to 23 days


Trimethoprim/sulfadiazine: 5–10 mg/kg trimethoprim combined with 25–50 mg/kg sulfadiazine PO q24h for 6 days to dogs over 4 kg; dogs under 4 kg BW are given half this dosage for 6 days




Thiamidine derivatives Amprolium: 100–200 mg total PO q24h for 7–12 days; in drinking water (sole source) at 30 ml (9.6% solution)/gal for up to 10 days; in food at 250–300 mg (20% powder) q24h for 7–10 days



Sulfonamides Sulfadimethoxine: 55 mg/kg PO q24h for 1 day, then 27.5 mg/kg PO q24h for 14–20 days



Triazine derivatives

Toltrazuril: 9 mg/kg BW PO once


Ponazuril: 50 mg/kg BW PO q24h for 3 days



Cats Sulfonamides Sulfadimethoxine: 55 mg/kg PO q24h for 1 day, then 27.5 mg/kg PO q24h for 14–20 days



DHFR/TS inhibitors Trimethoprim/sulfadiazine: 5–10 mg/kg trimethoprim combined with 25–50 mg/kg sulfadiazine PO q24h for 6 days to cats over 4 kg; cats under 4 kg BW are given half this dosage for 6 days.



Thiamidine derivatives Amprolium: 110–220 mg/kg PO q24h for 7–12 days; in drinking water (sole source) at 1.5 tsp (9.6% solution)/gal for up to 10 days; 150 mg/kg PO combined with sulfadimethoxine at 25 mg/kg PO q24h for 14 days.



Triazine derivatives

Toltrazuril: 18 mg/kg BW PO once


Ponazuril: 50 mg/kg BW PO q24h for 3 days


aThe use of nitroimidazoles in food-producing animals is strictly prohibited by the US FDA. Cattle receiving metronidazole should never enter the food chain.


bSee text for discussion of toxicity.


cDihydrofolate reductase/thyamidine synthase inhibitors.


dRegimen should be followed up with decoquinate therapy.


Table 42.2 Drugs licensed for the treatment of coccidiosis in food animals
























































































































































































































Species Drug Trade name Regulatory information
Chickens Roxarsone Ren-O-Sal®, Roxarsone 10% Type A Medicated Article, combination products available Not for use in laying hens; 5-day slaughter withdrawal for noncombination products, no longer marketed
            Decoquinate Deccox® Type A Medicated Article, combination products available Not for use in laying hens; no withdrawal necessary for noncombination products
            Clopidol Cloyden 25®, combination products available Not for use in laying hens; 5-day slaughter withdrawal for noncombination products
            Robenidine Robenz®, combination products available Not for use in laying hens; 5-day slaughter withdrawal for noncombination products
            Amprolium Amprol 25%, CORID 25% Type A Medicated Article, combination products available No withdrawal necessary for noncombination products
            Dinitolmide Zoamix® Not for use in laying hens; no withdrawal necessary
            Nicarbazin Nicarbazin, combination products available Not for use in laying hens; 4-day slaughter withdrawal for noncombination products
            Halofuginone Stenerol®, combination products available Not for use in laying hens; 4-day slaughter withdrawal for noncombination products
            Lasalocid Avatec®, combination products available Not for use in laying hens; no withdrawal necessary for noncombination products
            Maduramicin Cygro® Not for use in laying hens; 5-day slaughter withdrawal for noncombination products
            Monensin Coban®, combination products available Not for use in laying hens; no withdrawal necessary
            Narasin Monteban®, combination products available Not for use in laying hens; no withdrawal necessary
            Semduramicin Aviax®, combination products available Not for use in laying hens; no withdrawal necessary for noncombination products
            Salinomycin Bio–Cox®, Sacox® Not for use in laying hens; no withdrawal necessary
            Diclazuril Clinacox®, combination products available Not for use in laying hens; no withdrawal necessary for noncombination products
           

Ormetoprim/sulfadimethoxine

 Rofenaid®, combination products available Not for use in laying hens; 5-day slaughter withdrawal for noncombination products
            Sulfamethazine Sulmet® Drinking Water Solution Not for use in laying hens; 10-day slaughter withdrawal for noncombination products
Turkeys Roxarsone Ren-O-Sal®, Roxarsone 10% Type A Medicated Article, combination products available Not for use in laying animals; 5-day slaughter withdrawal for most products, no longer marketed

Clopidol Cloyden 25®, combination products available Not for use in laying animals; 5-day slaughter withdrawal for noncombination products

Amprolium Amprol 25%, CORID 25% Type A Medicated Article, combination products available No withdrawal necessary for noncombination products

Dinitolmide Zoamix® Not for use in laying animals; no withdrawal necessary

Halofuginone Stenerol®, combination products available Not for use in laying animals; 7-day slaughter withdrawal for noncombination products

Lasalocid Avatec®, combination products available Not for use in laying animals; no withdrawal necessary for noncombination products

Monensin Coban®, combination products available Not for use in laying animals; no withdrawal necessary for noncombination products

Diclazuril Clinacox®, combination products available Not for use in laying hens; no withdrawal necessary


Ormetoprim/sulfadimethoxine

 Rofenaid®, combination products available Not for use in laying animals; 5-day slaughter withdrawal for noncombination products

Sulfamethazine Sulmet® Drinking Water Solution Not for use in laying hens; 10-day slaughter withdrawal for noncombination products
Cattle Decoquinate Deccox® Type A Medicated Article, combination products available Not for use in lactating dairy cattle; approved for preruminating calves; no withdrawal necessary for noncombination products

Amprolium Amprol 25%, CORID 25% Type A Medicated Article, combination products available Not for use in preruminating calves; 1-day slaughter withdrawal

Sulfamethazine Sulmet® Oblets, Sulfamethazine sustained release bolus Not for use in lactating dairy cattle; 8 to 10-day slaughter withdrawal for individual products

Sulfaquinoxaline Sulfa-nox Liquid Not for use in lactating dairy cattle; 10-day slaughter withdrawal for noncombination products
Sheep Decoquinate Deccox® Type A Medicated Article, combination products available Not for use in lactating sheep; no withdrawal necessary for noncombination products

Lasalocid Bovatec®, numerous others and combination products available Not for use in breeding animals; no withdrawal necessary for noncombination products
Goats Decoquinate Deccox® Type A Medicated Article, combination products available Not for use in lactating goats; no withdrawal necessary for noncombination products

Monensin Rumensin® Not for use in lactating goats; no withdrawal necessary
Swine Toltrazuril Baycox® Extralabel drug use, contact regulatory agencies for withdrawal times
Rabbits Diclazuril Clinicox® Extralabel drug use, contact regulatory agencies for withdrawal times

Lasalocid Avatec/Bovatec®, numerous others and combination products available No withdrawal necessary for noncombination products

Sulfaquinoxaline SQ 40% Medicated feed 10-day withdrawal
Pheasants Amprolium Amprol 25%, CORID 25% Type A Medicated Article, numerous others and combination products available No withdrawal necessary for noncombination products
Chukar partridges Lasalocid Avatec/Bovatec® No withdrawal up to 8 weeks of age

Ormetoprim/sulfadimethoxine Rofenaid® Not released into wild before 18 weeks and can be used only up to 8 weeks of age
Bobwhite quail Monensin Coban®, combination products available Not for use in laying hens; no withdrawal necessary

Salinomycin Bio-Cox®, Sacox® No withdrawal necessary
Ducks Ormetoprim/sulfadimethoxine Rofenaid® Not for use in breeding animals or animals producing eggs for human consumption; 5-day slaughter withdrawal

Please see text for further explanation of dosing and toxicities. Regulatory information is applicable to drugs used in the United States, and is current only as of the writing of this chapter. Please consult the label directions on all products prior to administration because extralabel use of feed additives is prohibited by the US FDA.


Nitroimidazoles


Spectrum:

Giardia lamblia, Balantidium coli, Entamoeba histolytica, Tritrichomonas foetus, Pentatrichomonas hominis, Trichomonas gallinae, Histomonas maleagridis, Trypanosomas spp.


Drugs included:

metronidazole, tinidazole, ronidazole, dimetridazole, ornidazole, carnidazole, benznidazole, ipronidazole, and secnidazole (Figure 42.1).




















































Name Chemical name (Empirical formula) [Molecular weight] Chemical structure
Dimetridazole 1,2-dimethyl-5-nitro-1H-imidazole Image described by caption and surrounding text
            (C5H7N3O2)
            [141.13]
Ipronidazole 1-methyl-2-(1-methylethyl)-5-nitro-1H-imidazole Image described by caption and surrounding text
            (C7H11N3O2)
            [169.18]
Metronidazole 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole Image described by caption and surrounding text
            (C6H9N3O3)
            [171.16]
Ronidazole 1-methyl-2-[(carbamoyloxy)methyl]-5-nitroimidazole Image described by caption and surrounding text
            (C6H8N4O4)
            [200.16]
Tinidazole 1-[2-(ethylsufonyl)ethyl]-2-methyl-5-nitro-1H-imidazole

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Feb 8, 2018 | Posted by in PHARMACOLOGY, TOXICOLOGY & THERAPEUTICS | Comments Off on Antiprotozoan Drugs

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