Flashcards in pharmacology 1st quiz TS Deck (229):
which antimicrobial drugs act on bacterial cell membrane?
which antimicrobial drugs interfere with bacterial cell wall synthesis?
which antimicrobial drugs interfere protein synthesis at 30s subunit?
which antimicrobial drugs act on 50s subunit?
which antimicrobials interfere with nucleic acid synthesis?
which antimicrobials interfere with folic acid synthesis?
which antimicrobials are narrow spectrum?
polymyxin b and colistin
which antimicrobials are bacteriostatic?
macrolides and lincosamides
what are the 3 efficacy predictors of antimicrobials?
type 1 - conc dependent
type. 2 time dependent
type 3 time dependent with pae (persistant suppression of bacteria)
what combo of antimicrobials produces additive effect?
what combo of drugs produces synergistic effect?
what combo of drugs produces antagonistic effect?
bactericidal with bacteriostatic
what is transduction (antibiotic resistance)?
bacteria virus transfers genes
how do bacteria get antibiotic resistant from uptake of genes in environment?
what ways can bacteria decrease accumulation of drugs inside them?
decrease permeability thru cell membrane of gram negatives
energy dependent active efflux of drug
what is the prerequisite of folic acid in bacteria?
what are the 5 enteric sulfonamides?
what does a triple sulfa bolus consist of?
sulfinilamide, sulfathiazole, sulfamethazine
which sulfonamide is hydrolzyed in the bowl?
which sulfonamide is split into 2 parts in intestine and treats dog coilitis?
ehat are the 2 moa of sulfonamides?
structural analog of PABA, gets substituted
act as antimetabolites and interfere with rna and dna
which. 2 sulfonamides can be used topically?
which sulfonamide should be used for opthalmic apps because of neutral ph?
how are sulfonamides metabolized?
acetylation in liver
what effect does alkaline urine have on the excretion of sulfonamides?
increases fraction of dose eliminated in urine
what are the 2 immunological based toxicities of sulfonamides?
kcs ( dry eye)
what is the non immunological effects of sulfonamide toxicity on kidney?
renal tubular blockage
because of dehydration, keep well hydrated and aciduria protects
does a combination of sulpha drugs increase or decrease their solubility?
increase ( law of independent solubility)
which sulpha drug causes hypoprothrombinemia in dogs and chickens?
what sulfa drug can cause aplastic anemia?
trimethoprim sulfadiazine ( potentiated sulfa)
which species can have hypoglycemia from taking sulfa drugs?
ducks and dogs
which breed of dog can get polyarthritis and hepatitis from sulfa drugs?
what gland may sulfonamides interfere with but is reversible?
What group is sulfonamides in efficacy predictors?
type 2 antimicrobials, therefore ideal dosing maximizes duration of exposure
What type of molecule are diaminopyramidines?
lipid soluble organic bases
Are diaminopyramidines bacteriocidal or bacteriostatic?
How do diaminopyramidines block bacterial folate synthesis?
reversibly binds and inhibits dihydrofolate reductase
Which diaminopyramidine inhibits folate synthesis in protozoa?
Which diaminopyramidine can be given orally to ruminants?
What are the 3 different diaminopyramidines?
Pyrimethamine, trimethoprim, and ormetoprim
Are potentiated sulfonamides bacteriostatic or bacteriocidal?
bacteriocidal (each one alone is bacteriostatic)
How do beta lactam antibiotics exert bactericidal activity?
interfere with transpeptidase enzyme that is responsible for formation of cross links (penicillin binding proteins - PBP)
What type of bacterial cell wall can beta lactams NOT penetrate?
What 2 beta lactam drugs are "natural penicillins"?
Which natural penicilllin can be given orally?
What are the 2 log acting formulations of Penicillin G?
What bacteria are resistant to natural penicillins?
Pseudomonas, enterobacteriaceae and penicillinase producing staph
What are the 3 groups of semi synthetic penicillins?
Penicillinase resistant penicillins
Broad spectrum (aminopenicillins)
extended spectrum (carboxypenicillins)
What 3 penicillinase-resistant penicillins have good oral absorption?
What are penicillinase-resistant penicillins used to treat mostly?
-bovine staph mastitis
What penicillinase-resistant penicillin can be formulated as an opthalmic ointment and treat staph and bacillus infections?
What are the two drugs in the broad spectrum penicillins?
What are some related esters of ampicillin? (prodrugs)
What 5 penicillins are in the extended spectrum group?
ticarcillin, carbenicillin, piperacillin, mezlocillin, azlocillin
Why can't procaine penicillin G be administered IV?
affects cardiac conduction system
What can be used to competitively inhibit penicillin excretion?
another organic acid, such as probenecid
Which penicillin is not excreted in urine?
What can sodium benzylpenicillin produce in dogs and cats?
ataxia and convulsions (inhibits GABA)
What drug can produce anaphylaxis and CNS disorders in small mammals and reptiles?
What can procaine and postassium penicillin salts administered IV as a rapid bolus induce?
acute cardiac toxicities
What salt form should you use when administering penicillins IV?
What are the 3 first generation cephalosporins that can be given orally?
What are the 3 first gen cephalosporins that can be given parenteral?
Which first gen cephalosporin has greatest gram negative activity?
What bacteria are 2nd gen cephalosporins better at killing than 1st gen?
gram negative because increased resistance to lactamases
Which drug is a "new generation" of cephalosporins?
ceftiofur (broader gram + activity)
How does ceftiofur compare to other 3rd gen cephalosporins?
better at strept
less activity against pseudomonas
What cephalosporin is 4th gen?
Which 2 cephalosporins have the best oral absorption?
What is the only 2nd gen cephalosporin that can penetrate cerebrospinal fluid?
What 3rd generation cephalosprins can attain high concentration in cerebrospinal fluid when meninges are inflammed?
What 2 cephalosporins can decrease platelet aggregation?
How does clavulanic acid and sulbactam potentiate penicillin?
competitive inhibitor of beta lactamases of bacteria
What are the two kinds of Cabapenems?
What must imipenems be administered with?
cilastatin (renal enzyme inhibitor)
What bacteria does imipenems have activity on?
gram negative aerobic
What is the adverse effect of imipenems?
How is meropenems different from imipenems?
What can be used against gram negative bacteria or pseudomonas if patient is allergic to penicillin?
How do antimicrobials that inhibit protein synthesis target bacterial ribosomes instead of the host?
affinity for 70s size (eukaryotes is 80s)
What 2 parts of protein synthesis can antibiotics interfere with?
elongation of polypeptide chain
What 2 groups of antibiotics act on the 30 S subunit to inhibit protein synthesis?
What 3 groups of antibiotics act on 50S subunit to inhibit protein synthesis?
chloramphenicol and derivatives
Are aminoglycosides bacteriostatic or bacteriocidal?
What are the 6 aminoglycoside drugs?
Why is one single dose of aminoglycosides q24 the same as many small ones?
post antibiotic effect (PAE)
What kind of bacteria do aminoglycosides act on?
aerobic gram negative bacteria
What aminoglycoside has the broadest spectrum?
Which bacteria has natural permeability barrier to aminoglycosides?
How are aminoglycosides administered?
parentally (never orally)
Where do aminoglycoside drugs concentrate in the body?
perilymph of the inner ear and in the renal cortex (attracted to phospholipids)
Why shouldn't aminoglycosides and diuretic agents be used concurrently?
dehydration --> nephrotoxicity
What can happen when aminoglycosides are in high plasma concentrations after bolus?
non depolarizing neuromuscular blockade
What are 3 ways bacteria can be resistant to aminoglycosides?
reduced permeability to drug
What is the efficacy predictor of aminoglycosides?
Type 1 - concentration dependent killing kinetics
How can renal uptake of gentamicin be inhibited?
alkalinizing the urine with sodium bicarbonate
Which aminoglycoside is too toxic for systemic use and used in topical applications?
Which aminoglycoside is effective against gram positive AND negative bacteria?
What aminoglycoside is effective against Pseudomonas in dogs and cats?
What are the 3 natural tetracyclines?
What are the 2 semi-synthetic tetracyclines?
Are tetracyclines bacteriostatic or bacteriocidal?
What do tetracyclines bind to?
30s ribosomal subunit
Which tetracycline is the treatment of choice for equine monocytic ehrlichiosis? (potomac horse fever)
What tetracycline is effective against penicillinase resistant strains of staph aureus?
What microorganisms are resistant to tetracyclines?
Which tetracycline is given IM?
Which tetracycline is more completely absorbed in GI tract?
What are the 2 most lipid soluble tetracyclines?
Minocycline and doxycycline
What two tetracyclines are metabolized in the body? How are they then removed?
doxy (bile diffusion) - can be used in renal failure
Why should IV (oxy?)tetracycline be given slowly?
chelates calcium in blood
What can IV injections of doxy in horses do?
induces cardiac arrhythmia -- sudden death
How does oral tetracycline alter microflora in horses?
proliferation of clostridium perfringens or salmonella --> colitis
What group of efficacy predictors does tetracycline belong to?
type 3 - time dependent killing and PAE
What is the mode of action for chloramphenicol?
binds to 50s subunit
What can happen in prolonged admin of chloramphenicol?
bone marrow suppression (esp in cats) mitochondrial ribosome similar to bacterial one
What other antibiotic can chloramphenicol compete with and should not be administered with?
Which 2 types of bacteria are resistant to chloramphenicol?
enterobacteriaceae (readily acquired)
Which chloramphenicol drug is only available orally?
Which chloramphenicol is hydrolyzed in small intestine by esterases?
Which chloramphenicol can be given IV/IM?
How is chloramphenicol metabolized and therefore which animal has a slower clearance time?
conjugated with glucoronic acid
Can you use chloramphenicol in food-producing animals?
Which chloramphenicols do not induce bone marrow stem cell damage?
What type of animals are most sensitive to chloramphenicol toxicity?
impaired liver fxn
What is the side effect in newborn humans that are treated with high doses of chloramphenicol?
Gray baby syndrome
Which bacterial enzyme inactivates chloramphenicol and is acquired by plasmids?
acetyltransferase (florfenicol resistant to it)
What semi-synthetic chloramphenicol derivative is more water soluble?
Which chloramphenicol derivative is more potent and can be used in food producing animals?
What efficacy predictor group is chloramphenicol?
type 2 - time dependent
What are the 6 macrolide antibiotics?
How do macrolides differ in their mode of action than chloramphenicols?
unable to cross mitochondrial membrane and do not effect bone marrow
Are macrolides bacteriostatic or bacteriocidal?
bacteriostatic at therapeutic levels
bacteriocial slowly against strep
How does pH effect the antimicrobial action of macrolides?
high pH - enhanced
low pH - suppressed
Which macrolide is used to treat pink eye?
What is the preferred route of admin of macrolides?
oral (injections painful)
Which macrolide is metabolized by the liver?
Which macrolide is fatal to horses?
Which macrolide has a type 3 efficacy predictor?
What 2 drugs are lincosamides?
What bacteria are not effected by lincomycin?
Which lincosamide is more lipid soluble and can cross BBB?
How are lincosamides excreted?
What animals should lincosamides not be used in?
chinchillas, guinea pigs, hamsters
What efficacy predictor group is lincosamides?
What 2 groups of antimicrobials inhibit DNA replication?
What antimicrobial drug inhibits RNA synthesis?
What are the 3 first generation fluorquinolones?
What are the 4 third generation fluoroquinolones?
What are the 7 2nd generation fluorquinolones?
What bacterial enzyme is inhibited by fluoroquinolones?
DNA gyrase enzyme
Which fluoroquinolone may have activity on anaerobes?
What type of bacteria are more susceptible to fluoroquinolones in an alkaline environment?
Enterobacteriaceae and other gram negative aerobes
What three conditions is pradofloxacin effective for against anaerobes, gram positives and gram negatives?
What are the two "new" generation fluoroquinolones?
What are the 2 factors that affect the action of fluoroquinolones?
Cations decrease activity
low pH decreases activity
Which fluoroquinolones can be given in water for poultry infections?
Which fluoroquinolone is not widely distributed in tissues?
Which 2 tissues do fluoroquinolones not achieve a high concentration?
Which fluoroquinolone is well distributed in bone, prostate and skin and all horse tissues?
What tissue does enrofloxacin, marbofloxacin and orbifloxacin achieve good levels?
Which 2 fluoroquinolones are highly excreted in milk?
Which fluoroquinolones have active metabolites?
Which fluoroquinolone exception is excreted through faeces instead of urine?
What are some of the side effects of fluoroquinolones?
What fluoroquinolone causes abnormalities in horses tendon cultures?
Why does fluoroquinolones given IV rapidly cause CNS effects?
inhibition of GABA
dont give to seizure patients
What is the most important bacterial resistance mechanism for fluoroquinolones?
increased efflux (alterations in gyrase enzyme and decreased uptake also mechanisms)
What efficacy group is fluoroquinolones?
Type 1 - max concentration
What is the MOA for bacitracin?
inhibits peptidoglycan synthesis
What are the indications for bacitracin?
topical tx of superficial infections in skin, mucosal surfaces, ear and eye
What is the MOA for novobiocin?
inhibits cell wall synthesis, RNA, DNA, protein, respiration
Do bacteria acquire resistance against novobiocin?
Yes, very quickly
What spectrum of activity does thiostrepton have? how is it administered?
gram + and some -
Which nitrofuran drug can have a carcinogec effect when administered chronically?
How are nitrofurans administered?
need acid environment to go into cell membrane
What is the MOA for virginiamycin and is it bacteriostatic or bacteriocidal?
inhibits protein synthesis at 23s ribosomal subunit
What is the clinical use of virginiamycin?
growth promotion in swine, turkeys and laying hens
What clinical uses is carbadox used for?
growth promotant in swine
tx swine dysentery, bacterial enteritis
What happens if there is a toxicity of carbadox?
hypoaldosteronism (>100 ppm)
What is the MOA for vancomycin? Bacteriocidal or static?
inhibits peptidoglycan synthesis
What should vancomycin be combined with to treat enterococcal infections?
What are the 2 adverse effects of vancomycin?
histamine release --> IV
What group of antibiotics is vancomycin in that is banned from using in food animals?
Is methenamine bacteriostatic or bacteriocidal
depends on pH of urine
What condition is methenamine used to treat?
UTI in small animals
What other antibiotic should not be administered with methenamine?
What 2 antibiotics interfere with the cell membrane?
colistin (polymyxin E)
Are polymyxins bacteriostatic or cidal?
Why are polymyxins used for "bowel sterilization" before sx?
not absorbed from GIT when given orally
What is polymyxin B effective against in gram negative bacteria infections?
How are most polymyxins given?
What can polymyxins be combined with to act synergistically against gram negative bacilli?
What is the MOA for metronidazole?
disrupts DNA structure
What type of bacteria is metronidazole most effective against?
systemic and enteric obligate anaerobic bacterial infections
What part of metronidazole can have a carcinogenic effect in rats?
a minor metabolite that evolved from splitting the metronidazole ring
Can nitroimidazoles be used in food producing animals?
NO - may be carcinogenic
What efficacy predictor group is metronidazole?
type 1 - concentration dependent
How is rifampin metabolized?
de-acetylation --> active metabolite
induces Cytochrome p450
How is rifampin excreted?
What are some of the adverse effects of rifampin?
hepatitis in dogs
what are the 5 bacteiostatic type drug groups?
Which antibiotic causes bowel sterilization?
What is it called when 2 static antibiotics work together?
What group of antibiotics is effected by cations and pH?
What cephalosporin is the only 2nd gen that can go into CSF?
What antibiotic treats swine dysentery but has hypoaldosteronism toxicity?
What are the antibiotics that are type 1 efficacy? (3)
What are the 5 bacteriostatic antibiotics?
chloramphenicol, macrolides, lincosamides (50S)
Which beta lactam has low immunogenic profile?
Which cephalosporins are excreted in bile?
Which bacteria are resistant to fluoroquinolones?
What is the first choice antibiotic for C. jejuni?
What is the first choice drug for mycoplasma sp?
What bacteria are susceptible to metronidazole?
obligate anaerobes (clostridium, fusobacterium)
Which antibiotics are carcinogenic?
Which antibiotic has good effect on pseudomonas and proteus?
Which drug group has arthropies and ocular toxicities?
What bacteria are resistant to lincomycin?
What are the susceptible bacteria groups of each of the cephalosporin generations?
First - gram +
2nd - gram -
3rd - better gram -
Ceftiofur - more gram +
Which drug group chelates calcium in teeth and bone?
What is the 4th generation cephalosporin?
Which drug group causes fatal enterocolitis in hind gut fermenters?
What are the 4 antibiotic groups banned in food animals?
Which antibiotics inhibit GABA?
What drug is combined with tetracycline for synergism against kennel cough?
Which antibiotics treat prostate infection?
Which macrolide causes cardio toxicity?