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116 Cards in this Set
- Front
- Back
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what is the general mechanism of action of beta lactams?
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inhibitors of cell wall synthesis
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What type of distribution in the body do beta lactams have?
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poor oral bioavailability
wide extracellular distribution, poor penetration into deep tissue renal elimination little/no metabolism |
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What are the two main adverse effects of beta lactams
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dose-dependent a- GI toxicity, relatively safe
allergies b- immediate/delayed reaction, hypersensitivity |
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basic penicillin drugs
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penicillin G, penicillin V,
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aminopenicillin drugs
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amoxicillin, ampicillin
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b-lactamase resistant penicillins
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methicillin, oxacillin
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extended spectrum penicillins
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ticarcillin, piperacillin
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eagle effect
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when you reach too high of a concentration, penicillins can loose their efficacy
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spectrum of regular/basic penicillins?
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gram +, esp. pasteurella
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spectrum of aminopenicillins
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gram +, pasteurella, some gram -
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spectrum of antistaphylococcal penicillins (methicillin, oxacillin)
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gram +, less efficient against gram + anaerobes and gram -
good against b-lactamase and anaerobic gram + |
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antipseudomonal penicillins (ticarcillin, piperacillin)
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good against G - more so than gram +
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What drugs do penicillins have synergy with?
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aminoglycosides and b-lactamase
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what can penicillin be degraded by? what type of half life do they have? what formulations combat this?
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degraded by GI amidase, bacterial B lactamase, acidity, alkalinity
short half life procaine and benzathine have prolonged half-lives |
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what toxicity does penicillin have?
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GI- dont use in guinea pigs, rabbits, etc
cardiovascular- do not give rapid iv INJECTION OR GIVE IV injection of procaine CNS toxicity Allergies- cross reacts with cephalosporins |
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What are some things you should be aware of with clinical use of penicillin
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Anti-pseudomonal penicillins- do not use empirically! NOT first line of Ab, limit vet use
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What drugs are beta lactams
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penicillins, cephalosporins, B lactamase inhibitors, Mono bactams, carbapenems
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What drugs are in the first generation of cephalosporins
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cefazolin, cephalexin, cephaloridine
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what drugs are in the second generation ofcephalosporin
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cefuroxime, cefotetan
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what drugs are in the third generation of cephalosporin
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ceftazine, cefovecin, ceftriaxone
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What type of activity do beta lactams have
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bactericidal, time dependent, PAE
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What is the spectrum of action for 1st gen cephalosporins
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gram +, modest gram - (includes b lactamase +)
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what is the spectrum of 2nd generation
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less gram +, more gram -
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what is the spectrum of 3rd gen?
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much less gram +, much more gram _ (includes pseudomonas and enterobacteria)
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Comparison of cephalosporin with penicillin sensitivity?
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Cephalosporins are less sensitive to GI amidase, B lactamase, alkalinity, and acid than penicillins. They have better oral bioavailability. They are more effective with puss and tissue debris
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Cefovecin- unique characteristic
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3rd gen cephalosporin for dogs and cats with LONG half life allowing 1 injection every 2 weeks
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Toxicity of cephalosporins
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GI- more so than penicillin
Nephrotoxicity Allergic reactions |
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Usage regulations for cephalosporins
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Overuse has lead to resistance to B lactams
Only can be for labeled usage in food animals! Use more carefully in future |
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B lactamase inhibitor drugs
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clavulanic acid and sulbactam
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How are b lactamase inhibitors clinically used?
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in combination with b lactamase sensitive penicillins to increase spectrum to B lactamase + gram +
ex. amoxicillin + clavulanic acid |
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What drug is a monobactam? What spectrum does it cover?
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aztreonam, covers most gram -
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what drug is a carbapenem? what spectrum does it cover?
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imipenem
widest spectrum of action! everything do not use empirically! |
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Peptide drugs
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glycopeptides (vancomycin)
polymyxin B bacitracin |
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What is the activity spectrum for vancomycin?
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inhibitor of cell wall synthesis, only gram +, time AND concentration dependent
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What is the PK and toxicity of glycopeptides
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give IV- poor PO
renal elimination nephrotoxicity, tissue toxicity |
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Glycopeptide clinical use
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Banned in food animals!!!
Do not use unless last resort, and after positive sensitivity and culture if there are no other options. no reliable dosages for vet med |
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polymyxin B activity and spectrum
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disrupts cell membrane and has an endotoxin effect
concentration dependent Only gram - |
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PK and toxicity of polymyxin B
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not absorbed orally, give local or IV, renal elimination, nephrotoxicity and neurotoxicity when used systemically
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Bacitracin activity and toxicity
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Cell wall synthesis inhibitor, mainly gram +, not absorbed orally, HIGH nephrotoxic effect when used systemically- use topically!
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Bacteriostatic
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do not kill the bacteria but make them more vulnerable to pt immune system.
normal defense mechanisms must participate |
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bactericidal
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kills the bacteria, can be bacteriostatic if given in suboptimal doses
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immunocompromised patients usually require what kind of antimicrobial
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bactericidal
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minimal inhibitory concentration
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smallest concentration of Ab tested that prevents the growth of a given bacteria in vitro
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concentration dependent drugs work best when
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Cmax/MIC ratio is maximized
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time dependent drugs work best when
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time period with plasma concentration > MIC is maximized
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Type A adverse effect reaction
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secondary to the mechanism of action of a drug, dose-dependent, predictable
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Type B adverse effect reaction
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unrelated to pharmacology of the drug, not dose-dependent, unpredictable. if immune mediated = drug allergy
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What are the three types of nucleic acid disrupters and an example of ea?
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DNA replication inhibitors-quinolone
RNA synthesis inhibitors-rifamycin DNA damaging agents-nitroimidazoles |
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what are three drugs that belong in the flouroquinolone family
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enrofloxacin, ciprofloxacin, orbifloxacin
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What type of activity do flouroquinolones have?
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bactericidal
concentration dependent- too high it will lose efficacy aerobic gram -, some gram + ineffective against anaerobes extra and intra cellular |
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What type of absorption, metabolism and elimination do flouroquinolones have
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oral absorption (decreased by cations)
minimal liver metabolism (except ciprofloxacin) renal elimination |
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adverse effects of flouroquinolones
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GI disturbance, articular and bone growth damage in juveniles and neonates, retinal degeneration (cats), tendon toxicity (avoid in athletes), neurotoxicity (avoid IV rapid), rapid resistance selection
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Explain concentration effects on flouroquinolones
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low: tx fails, rapid resistance
high: lowered efficacy pick low end of range when you know bacteria is sensitive and its healthy, pick middle when the bacteria might be resistant, pick high for immunocompromised and psuedomonas tx |
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what animals should you not use flouroquinolones in
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preggos, growing, athletes, off-label in food animals is banned
*do not use empirically/fist choice* |
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what kind of activity does rifamycin have
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bactericidal
concentration dependent most aerobic gram +, some gram - obligate anaerobes are resistant!! |
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Should you give rifampin in an animal that is on other drug therapy? why?
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no, because it affects liver enzymes and will modify the Pk of other drugs
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What are some adverse effects of rifampin
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hepatotoxicity-DOGS
bone marrow toxicity teratogenic |
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what animals should you use caution with give rifampin? what should you use to monitor
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avoid in preggos, caution in dogs, banned in food animals!
monitor CBC and liver panel |
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What is the activity of metronidazole
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bactericidal
time OR concentration dependent only active in anaerobic conditions!!! more gram - than gram + extra and intracellular protozoans |
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How can you administer metronidazole? what will it penetrate? what metabolism and elimination does it have?
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orally
penetrate deep tissue including CNS CYP450 and glucuronidase liver metabolism hepatic and renal elimination |
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what are some adverse effects of metronidazole
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unpalatable (can mix with ester benzoate)
GI toxicity Neurotoxicity-esp in dogs drug interactions due to liver metabolism carcinogenic and teratogenic |
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When should you not use metronidazole
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avoid in preggos and avoid long term use!!!
Banned in food animals |
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What categories of drugs inhibit ribosomal 30S
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aminoglycosides and tetracyclines
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what categories of drugs inhibit ribosomal 50S
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macrolides, lincosamides, pheicols
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what categories of drugs inhibit protein synthesis?
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aminoglycosides, tetracyclines, macrolides, lincosamides, pheicols
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what drugs are aminoglycosides
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streptomycin, spectinomycin, neomycin, gentamicin, amikacin
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how do aminoglycosides work
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inhibit protein synthesis by utilizing ozygen depending bacteria penetrtiation
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what activity do aminoglycosides have
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bactericidal, concentration dependent, PAE
mostly gram - only in aerobic conditions |
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what combination effects do aminoglycosides have
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addative effect with any cell wall/membrane disruptor
incompatible with penicillin in vitro antagonizes other protein synthesis inhibitors |
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what route should streptomycin be given? how is it distributed? how is it eliminated? metabolized?
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parenterally
extracellular distribution with poor deep tissue penetration renal elimination no liver metabolism |
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what type of environment affects spectinomycin and its drug family?
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inactivated in acidic environment, neutralized by acids, activity is decreased in presence of Ca, mg (divalent cations)
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what type of infection does neomycin and its family treat well?
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UTIs
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what adverse effects do gentamicin and its family have?
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rapid development of resistance, residues in food animals, ototoxicity, nephrotoxicity,
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what type of dosing regime is rec for amikacin and its family?
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once daily!, avoid using when risk factors are present, add fluid therapy, monitor blood and UA, follow label directions
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what drugs are in the family of tetracyclines
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tetracycline
oxytetracycilne chlortetracycline doxycycline |
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what type of activity do tetracyclines have
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bacteriostatic, time dependent
very broad spectrum |
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what combinations should you worry about with oxytetracycline and its family?
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antagonism
do not use with antacids containing Ca, Mg, Al, minoerals, iron, food, or milk |
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How is chlortetracycline and its family absorbed? eliminated?
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absorbed orally
enters deep tissues including CNS liver and renal elimination |
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what tetracycline is not eliminated by the kidneys
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doxycycline
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what adverse effects does doxycycline and its family have?
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resistance and residues, GI upset, inflammation at injection site, binds to the bone
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what drugs are in the macrolide family
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erythromycin, spiramycin, tulathromycin, tylosin, tilmicosin
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what type of activity does erythromycin and its family have
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bacteriostatic
time dependent aerobic gram + anaerobes are resistant |
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what environment inactivates spiramycin and it's family?
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acid environment
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What other two effects should you consider when giving drugs like tulathromycin?
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prokinetic
antiinflammatory |
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what drug interactions should you be concerned with if you give tylosin
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antagonism with other ribosome inhibitors
CYP450 inhibition |
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which class of drugs should you worry about resistance-when if resistance is created for one class of drugs it also creates resistance for the other two?
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50S ribosome protein inhibitors
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what drug family is unstable in acidic environment, enters most deep tissues but not the CNS, and has liver elimination and liver metabolism?
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macrolides
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which drug in the macrolide famly can cause cardiotoxicity
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tilimicosin when given parenterally
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What drugs are included in the lincosamide family
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lincomycin, clindamycin,
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what type of activity does clindamycin and its family have
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bacteriostatic
time dependent gram +, most obligate anaerobes extra and intracellular bacteria |
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which family of protein inhibitors has good oral absorption (but decreased by food), enters most deep tissues except the CNS, and has liver elimination and liver metabolism?
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lincosamides
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what adverse effects does pirlimycin and its family have
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GI upset, peripheral NM blockage, cardiac depression
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how does the use of lincosamides compare to penicillin? what is it not sensitive to?
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beta-lactamases
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what drugs are apart of the phenicole family
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cholamphenicol, florfenicol
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what type of activity does florfenicole and its family have?
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bacteriostatic
time dependent broad spectrum extra and intracellular |
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what are the specific adverse effects that cholamphenicol has
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bone marrow toxicity (esp cats and it tx is over 10d)
banned in food animals |
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what specific adverse effects does florfenicol have? what specific requirement should you keep in mind while using it?
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gi disturbance
only 2 approved injections in food animals |
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What are two folate synthesis inhibitors
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sulfonamides and diaminopyrimidines
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What are some examples of sulfonamides
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sulfamethxazole, sulfadiazine, sulfadimethoxine
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What is the mechanism of sulfonamides
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compete with PABA to inhibit folic acid synthesis in bacteria, specifically inhibit dihydropteroate
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Are Sulfonamides bacteriocidal/static? time/dose dependent? Spectrum?
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Bacteriostatic
Time dependent Gram +, gram -, aerobes, extracellular bacteria |
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Where are sulfonamides metabolized and eliminated? What is their distribution in the body
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Liver metabolism
mixed liver and renal elimination good penetration in fluids- inc. CSF and prostate |
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Adverse effects of sulfonamides
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relatively safe
-thyroid function inhiition -keratoconjunctivitis sicca -immune-mediated blood cytopenia -rare allergic reactions |
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What drug family are sulfonamides in
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metabolism inhibitors
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What animal can you not use sulfonamides in?
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lactating dairy cattle
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what family are diaminopyrimidines in
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metabolism inhibitors
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what are some examples of diaminopyrimidines
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-oprims
trimethoprim, ormetoprim |
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What is diaminopyrimidines mechanism of action
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prevent activation of folic acid into folinic acid
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Are diaminopyrimidines bacteriostatic/cidal? time/dose dependent? spectrum?
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Bacteriostatic
Time-dependent Gram -, gram +, aerobes, extra AND intra cellular bacteria good penetration of tissues inc CNS and prostate |
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What kind of metabolism, excretion, and absorption routes do diaminopyrimidines have
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liver metabolism
liver excretion well absorbed orally |
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What are some adverse effects of diaminopyrimidines
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blood cytopenia when used at high doses and/or for more than 3 weeks
avoid in pregnant animals-folic acid deficiency (may supplement with folic acid) |
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What are some advantages of potentiated sulfonamides
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potentially bacteriocidal
extension of spectrum to intracellular microbes Extension of tissue penetration |
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What family of drugs does nitrofuantion belong to? what is its mechanism of action
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metabolism inhibitors
deprive bacteria of key energy productoin pathway, also damages DNA |
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What spectrum does nitrofurantion have? bacteriostatic/cidal? extra/intracellular?
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Gram +, gram-, aerobic, anaerobic= broad spectrum!!!
Extracellular both bacteriostatic and cidal |
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How is nitrofurantion metabolized and excreted?
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liver metabolism
renal excretion |
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what should you worry about with nitrofurantion
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drug allergies
banned in food animals NOT first line choice |
