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51 Cards in this Set
- Front
- Back
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name the 1 nitroimidazole
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- metronidazole
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can nitroimidazoles be used for food animals?
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NO
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spectrum for nitroimidazoles
aerobic or anaerobic |
anaerobic only
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MOA nitroimidazoles
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- reduces nitro group on anaerobic bacteria
- forms unstable metabolites - metabolites break DNA strands and inhibit repair enzymes |
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besides anaerobic bacteria, what other bugs do nitroimidazoles have activity against?
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- Entamoeba
- Giardia - Balantidum coli - Trichomonas |
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PK of metronidazole in dogs:
ROA %F |
- well absorbed after oral admin
- 50-100% bioavailability in dogs |
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why is metronidazole banned in food animals?
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- carcinogenic effect observed in lab animals
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side effect of metronidazole in horses
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inappetance
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AE of high dose metronidazole in dogs and cats
what should dose be? |
- acute CNS toxicosis
- 10-15 mg/kg BID |
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name the two antimicrobials with Veterinary Feed Directive status
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- pulmotil
- Aquaflor |
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name the 2 Phenicols
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- Chloramphenicol
- florfenicol |
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solubility for Phenicols
what does this do to the VD |
- very lipid soluble
- high VD |
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how could a bacteria be resistant to chloramphenicol but susceptible to florfenicol
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- florfenicol only has 1 acetylation site for inactivation
- chloramphenicol has 2 sites |
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MOA of Phenicols
what ribosomal subunit do they bind to? |
- protein synthesis inhibitors
- 50s subunit |
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chloramphenicol AE
what disease does it cause? |
- chloramphenicol also inhibits protein synthesis in bone marrow
- causing aplastic anemia |
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chloramphenicol use in food animal
why or why not |
- NO
- potential for irreversible aplastic anemia |
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chloramphenicol ROA
dogs |
- oral tablets only for dogs
- powder for injection |
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florfenicol ROA
cattle swine fish |
- IM and SC for cattle
- oral solution in water for swine - feed additive in fish |
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fetal and neonate chloramphenicol elimination
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- much slower than adults
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major AE of chloramphenicol in dogs
what drug ixn |
- prolongs the activity of barbituates
- do not use for dogs on phenobarbital |
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***
Name the drugs contraindicated for use on dogs with phenobarbital |
- Cephalexin
- enrofloxacin - chloramphenicol - imipenam |
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PD: efficacy dependent on?
chloramphenicol florfenicol static or cidal for each? |
- time above MIC
- chloramphenicol considered bacteriostatic - florfenicol considered bactericidal |
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human chlorampenicol AE
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aplastic anemia
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name the phenicol with an AE of dose-related bone marrow suppression in all veterinary species with prolonged therapy
is this reversible? |
- chloramphenicol
- usually reversible |
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in what two disease states will chloramphenicol accumulation occur?
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- patients with impaired renal and/or hepatic function
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Gray baby syndrome in humans is caused by what drug
what is the cause? |
- chloramphenicol
- circulatory collapse due to inability to conjugate or excrete the conjugate effectively |
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WDT for florfenicol
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- 28 days for SC
- 38 days for IM |
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can florfenicol be used in lactating dairy cows?
veal calves? |
no
no |
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is there any tolerance for residue in a veal calf or cull dairy cow for florfenicol?
what does this do to the WDT for cull cows |
- zero tolerance
- change from 38 days to 90 days |
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AE of florfenicol in horses
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GIT distrubances
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name 4 intermediate acting sulfonamides
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- sulfadimethoxine
- sulfamethoxazole - sulfamethazine - sulfadiazine |
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name the 2 long acting sulfonamindes
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sulfadimethoxine
sulfamethazine |
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name the enteric sulfonamide
what species should you be cautious with |
sulfasalazine
be cautious with cats |
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name the diaminopyrimidine
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Ormetoprim
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most common combination therapy of sulfonamide and diaminopyrimidine
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trimethoprim/sulfamethoxazole
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sulfonamides and lactating dairy cattle
can they be used? in what way? |
- use is prohibited in the US
- except for approved use of sulfadimethoxine, sulfabromomethazine, sulfaethoxypyridazine |
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sulfa drugs
pH solubility |
- sulfa drugs are weak acids
- not water soluble in weak acids |
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sulfonamide MOA
3 steps |
- compete with PABA for folic acid synthesis
- decreased RNA - inhibition of protein synthesis |
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in what environment to sulfa drugs lose their activity?
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sulfas lose activity in the presence of cellular debris
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sulfas
static or cidal what could change this? |
- considered static
- unless combined with trimethoprim, then may be cidal |
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diaminopyrimidine and sulfa drug combo
static or cidal? does this change the spectrum? |
- cidal to susceptible microbes
- doesnt change spectrum, just changes the efficacy against the microbes |
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resistance to sulfas?
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common
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sulfadimethoxine trade name
ROA |
- Albon
- IV - oral boluses, tablets, powders |
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are sulfas absorbed well oral and parenteral?
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- yes
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how is a dosing regimen for sulfa drugs accomplished
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- usually given a "loading dose" for first dose, followed by a maintenance dose
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how are sulfas excreted?
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- renal excretion
- biotransformation |
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what effect does alkalinizing the urine have on solubility of sulfa drugs?
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- alkalinizing the urine increases solubility
- in acidic urine, crystalluria more prone to occur |
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are there veterinary specific breakpoints for sulfa drugs?
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no
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ocular AE in dogs given sulfa drugs
other AE of sulfas dogs |
- keratoconjuctivitis sicca
- neutropenia - bone marrow depression, hypersensitivity rxns, fever, vomiting, immune-mediated thrombocytopenia |
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other AE of sulfa drugs (general)
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- possible crystalluria
- enteric flora alteration - induce thyroid hypoplasia |
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are sulfa drugs used as first line of defense drugs?
why or why not? |
- no
- due to several potential AE |
