Antiprotozoan Drugs Flashcards
What 5 protozoa are of veterinary importance?
- Babesia divergens
- Trichomonas foetus
- Toxoplasma gondii
- Trypanosomas cruzi
- Giardia duodenalis
What benzimidazoles and pro-benzimidazole have antiprotozoan characteristics? What activity does it have? What activity does it lack?
- Albendazole
- Fenbendazole
- Febentel
Giardia spp.
antibiotic activity —> avoids affecting the normal flora, just affects Giardia
What aminoglycoside has antiprotozoal characteristics? How is it used in different species?
Paromomycin
- approved for use in cattle
- extra-label use in cats, dogs, cattle, and goats
What is the mechanism of action of Paromomycin? What is a common adverse effect?
aminoglycoside - interferes with bacterial protein synthesis
renal toxicity —> GI damage allows it to reach systemic circulation
What 2 protozoal diseases is Paromomycin used against? What activity does it lack?
- Giardiasis
- Cryptosporidiosis
little activity against intestinal bacteria
What azalide (macrolide) has antiprotozoal activity? What is its mechanism of action? What activity does it have?
Azithromycin (used in cattle)
inhibits protein synthesis by binding to the 50S ribosomal unit
activity against mycoplasma and cryptosporidium
What lincosamide has antiprotozoal activity? What is its mechanism of action? What 2 protozoal diseases is it used to treat?
Clindamycin (used in dogs and cats)
inhibits protein synthesis at the 50S ribosome subunit
- Toxoplasmosis
- Neosporosis
What 3 dihydrofolate reductase/thymidylate synthase (DHFR/TS) inhibitors have antiprotozoal activity?
- Trimethoprim
- Pyrimethamine
- Ormetoprim
What 2 DHFR/TS inhibitors are used to treat equine protozoal myelitis?
Trimethoprim or Pyrimethamine combines with sulfadiazine
What 2 DHFR/TS inhibitors are used to treat coccidiosis, toxoplasmosis, and neosporosis in dogs and cats?
- Trimethoprim combined with sulfadiazine in dogs and cats
- Ormetoprim combined with sulfadimethoxine in dogs
What DHFR/TS inhibitors are used to treat coccidiosis in broiler chickens and turkeys?
Ormetoprim combines with suldadimethoxine
What is the mechanism of action of DHFR/TS inhibitors? What other drug is it most commonly combined with?
blocks dihydrofolate reductase responsible for the synthesis of tetrahydrofolic acid, the active form of folic acid
sulfonamides (1:5)
What 4 nitroimidazoles have antiprotozoal activity? How is their use controlled in food-producing animals?
- Metronidazole
- Tinidazole
- Ronidazole
- Benznidazole
prohibited by the FDA —> cattle receiving metronidazole should no enter the food chain
What 2 nitroimidazoles are used to treat trichomoniasis? What animals are they used in?
- Metronidazole - cats and cattle
- Tinidazole - cats
Ronidazole no longer approved for use in cats
What 2 nitroimidazoles are used to treat giardiasis? What animals are they used in?
- Metronidazole - dogs, cats, and horses
- Tinidazole - dogs, cats
What nitroimidazole is used to treat trypanosomiasis in dogs?
Benznidazole
The mechanism of action of nitroimidazoles is not completely understood. What is suspected to be the mechanism of action?
disrupts DNA and nucleic acid synthesis
Where are nitroimidazoles metabolized? Eliminated?
liver
urine and feces - metabolites/unchanged drug