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100 Cards in this Set
- Front
- Back
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type of drug: penicillin G
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Penicillins
beta-lactam |
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type of drug: penicillin V
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Penicillins
beta-lactam |
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type of drug: nafcillin
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Antistaphylococcal penicillins
beta-lactam |
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type of drug: oxacillin
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Antistaphylococcal penicillins
beta-lactam |
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type of drug: cloxacillin
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Antistaphylococcal penicillins
beta-lactam |
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type of drug: dicloxacillin
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Antistaphylococcal penicillins
beta-lactam |
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type of drug: methicillin
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Antistaphylococcal penicillins
beta-lactam |
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type of drug: ampicillin
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Extended-spectrum penicillins
beta-lactam |
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type of drug: amoxicillin
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Extended-spectrum penicillins
beta-lactam |
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type of drug: ticarcillin
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Antipseudomonal penicillins
beta-lactam |
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type of drug? piperacillin
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Antipseudomonal penicillins
Beta-lactams |
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what are the 2 places on gram positive cell walls that we attack with antibiotics?
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peptidoglycan
peptide cross-links |
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what is a major virulence factor in gram negative cell walls?
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beta lactamase
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the outer membrane of gram negative cell wall has what property?
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permeability barrier
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what is the important peptidoglycan structure on the gram positive bacteria?
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D-Ala D-Ala at the end
it is where vancomyosin binds |
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what blocks the adding of 2 D-ala's to the end of the peptide chain of thecell wall for bacteria?
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Cycloserine prevents this from happening
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what is bactoprenol?
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it is responsible for carrying bacterial building blocks across the plasma membrane for cell wall synthesis
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what does vancomycin do?
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binds to the 2 d-ala's that attempt to put the building blocks into the cell wall of the bacteria
This prevents cross-linking & elongation of peptidoglycan (blocks transglycosylase) |
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what does bacitracin do?
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prevents the recycling of bactoprenol (remember that bactoprenol is responsible for carrying bacterial building blocks across the plasma membrane for cell wall synthesis)
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what does transpeptidase do?
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builds amino acid cross link between building blocks of the bacterial cell wall
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how does penicillin work? (b-lactams)
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block transpeptidation step …block cross linking of peptidylglycan chains
penicllin looks like the alanine-alanine bridge, and uses up all the transpeptidase! |
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what are the 3 basic steps of synthesis of bacterial cell wall? what blocks each stage?
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1: occurs in cytoplasm – provides building blocks (cycloserine blocks this)
2: : occurs as building blocks pass through the plasma membrane (vancomycin or bacitracin) 3:Occurs outside the plasma membrane and involves cross-linking of peptidylglycan strands (b-lactams) |
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What do autolysins do?
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Look this up.. it was on slide 22
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are beta-lactam bactericidal or static?
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bactericidal
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are beta-lactams time or concentration dependent?
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Effect is directly proportional to amount of TIME the drug concentration at the site of infection is ABOVE the MIC of the organism
TIME DEPENDENT! |
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What is essential for b-lactams to work (2)? functions?
*** gotta know this one |
1. intact beta-lactam ring is essential for binding to PBPs and antimicrobial activity
2. R side chain … determines spectrum of antibacterial activity and pharmacological properties (e.g., affinity for PBP, resistance to penicillinase, ability to penetrate G- outer membrane, resistance to stomach acid, PK) |
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what is the difference between Pen G and Pen V?
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G: is acid labile … poor oral bioavailability
V: more stable in acid so “better” oral availability Remember: V is not IV |
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what is the b-lactam bond?
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Pen G is ____ spectrum
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narrow
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what does Pen G mostly treat?
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Gram Positives
note also treats: a few gram negatives (like Neisseriae meningococci) some anaerobes and spirochetes (syphilis) |
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what are some of the bugs with resistnace to penicillin G?
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> 90% of Staphylococcus a
~ 5 % of Streptococci Most of Neisseria gonococci Pen G no longer a DOC |
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what are 3 areas that penicillin cannot treat infection in?
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prostate
ocular CSF |
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Can penicillin cross the BBB? Can it be used in Meningitis?
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Do not readily cross BBB
… but … with inflamed meninges Penicillins more easily enter the CSF Therapeutic levels can be reached Meningitis … Penicillin may be used Often used in combination with another antimicrobial |
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Pen G has a short half-life, what can slow this process?
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Probenecid
blocks renal tubular secretion of penicillin |
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if Pen G has a short half-life, how does it have a low/prolonged drug level?
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it is given with benzathine which gives a slow release from the injection site
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although Penicillin G has the lowest toxicity potential of all antimicrobials, what is the most common adverse effect?
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Allergic (hypersensitivity) Reactions
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what is a breakdown product of penicillin G? what is the importance of this?
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Penicilloic acid
acts as a hapten.... making a huge immune reaction....leading to penicillin allergy |
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are diarrhea and GI intolerance allergic reactions of penicillin G?
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NO
but they do occur, just not allergic |
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aside from allergic reactions, what is a possible major problem with use of penicllin G?
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Neurotoxicity
Most likely at high doses(intrathecal admin or renal failure) Coma, seizures, hyper-reflexia |
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what causes superinfections?
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loss of normal flora from use of broad spectrum agents
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what type of bacteria is generally resistant to penicillin g?
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Gram negative
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What is the most common resistance component to penicillin G?
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Penicillinase production
(beta lactamase) |
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why does penicillin not affect mycoplasma?
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NO CELL WELL (and that is the mech of action for penicillin
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What happens in MRSA?
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Beta-lactams can’t bind to target because transpeptidases are mutated
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how do beta lactamases work?
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break the beta lactam bond on the beta lactam ring
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what type of b-lactamases give resistance? what do they give resistance to?
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Plasmid encoded
mediate resistance to penicillins and 1st & 2nd generation cephalosporins |
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what are extended spectrum b-lactamases? where are these seen in most commonly (2)?
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can hydrolyze penicillins AND CEPHALOSPORINS (all generations!)
--this is bad! In gram negative bacteria: most commonly Klebsiella and e coli |
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what are the antistaphylococcal penicillins? 4
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Oxacillin
Nafcillin Cloxacillin Dicloxacillin |
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what are the b-lactamase resistant penicllins?
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Antistaphylococcal penicillins:
Oxacillin Nafcillin Cloxacillin Dicloxacillin |
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will antistaphylococcal agents work against MRSA?
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NO
PBP (drug target) is altered in MRSA ... … and the drugs can’t bind!! |
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oxacillin causes what side-effect?
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hepatotoxicity
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what are the 2 extended spectrum penicillins?
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ampicillin
amoxicillin |
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what would you want to use for gram negatives (e coli, n. meningitidis)? note: these would NOT work on beta-lactamase bugs
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Extended spectrum penicillins: Ampicillin & Amoxicillin
Not effective against beta-lactamase producers (3rd and 4th gen cephalosporins work against gram neg and would work against beta-lactamase bugs) |
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what is the only oral pen that food does not interfere with absorption?
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Amoxicillin
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Ampicillin & Amoxicillin spectrum of activity?
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similar to Pen G (gram +) and extends to:
H influenzae E. coli Listeria sp. Proteus Salmonella HELPS |
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clinical uses fro ampicillin and amoxicillin?
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Sinusitis,
otitis, UTIs, pneumonia (SOUP) |
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what do you normally use with ampicillin?
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Ampicillin is frequently used (synergistic) with an
AMINOGLYCOSIDE (gentamicin) for broad range coverage in serious infections |
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DOC for Listeria meningitis
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Ampicillin
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why do you use a bactericidal drug in meningitis?
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no immune response in spinal column!
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what are the Antipseudomonal penicillins?
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ticarcillin
piperacillin |
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spectrum of activity for ticarcillin and piperacillin?
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Pen G (gram pos) + HELPS + Pseudomonas, Klebseilla, and Serratia
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ticarcillin and piperacillin are used with what?
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in combination with an aminoglycoside
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what has the broadest spectrum of the penecillins?
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Piperacillin
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sodium overload is a potential with what penicillin drug?
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Antipseudomonal penicillins (Ticarcillin & Piperacillin)
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do beta lactamase inhibitors have antimicrobial activity?
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not intrinsically they potentiate the effect of the anti-biotics
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how do Beta lactamase inhibitors work?
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Binds to B-lactamase and inactivates the enzyme
Because they look like a penicillin Suicide inhibitors Binding is irreversible |
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as you shift from 1-4 generation cephalosporins, what happens? (3)
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increasing activity against Gram negative (decreasing against gram pos)
Increasing resistance to B-lactamases Increasing ability to cross BBB |
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what class of cephalosporin can you use to treat meningitis?
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3rd and 4th... able to cross the BBB
Note: penecillin can work b/c you have enough "leakiness" for it to fit in |
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Cephalexin is what kind of drug?
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1st Generation
Cephalosporins |
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Cefazolin is what kind of drug?
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1st Generation
Cephalosporins |
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Cefoxitin is what kind of drug?
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2nd Generation
Cephalosporins |
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Cefaclor is what kind of drug?
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2nd Generation
Cephalosporins |
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Cefprozil is what kind of drug?
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2nd Generation
Cephalosporins |
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Ceftriaxone is what kind of drug?
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3rd Generation
Cephalosporins |
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Ceftazidime is what kind of drug?
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3rd Generation
Cephalosporins |
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Cefotaxime is what kind of drug?
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3rd Generation
Cephalosporins |
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Cefdinir is what kind of drug?
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3rd Generation
Cephalosporins |
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Cefepime is what kind of drug?
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4th Generation
Cephalosporins |
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specturm of activity for cephalosporins?
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… generally like ampicillin (G+ & HELPS) ... but varies with generation
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cephalosporin: bactericidal or static?
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bactericidal
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what are the 2 resistances to cephalosporins?
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Penicillinases and cephalosporinases
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In general … cephs are more resistant to breakdown by what enzymes?
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Penicillinases and cephalosporinases
Klebsiella, E Coli, Pseudomonas, Enterobacter, (ESBL can breakdown penicillins & cephs) |
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what is an adverse effect of cephalosporins? 2
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ALLERGIC reactions
superinfection |
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2 major clinical indications of cephalosporins?
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Can be useful alternative for penicillin allergic patients (if mildly allergic)
Frequently used for surgical prophylaxis (especially 1st generation) |
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order gram positive coverage for the different generations of cephalosporins
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1>2>3
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order gram negative coverage for the different generations of cephalosporins
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3>2>1
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Resistance to beta lactamases increases from ___ to ___ generation
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increases from 1st to 4th generation
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Hypoprothrombinemia is a side-effect of what? what is it?
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Cephalosporins
Coagulation abnormalities Disturbs synthesis of vitamin K-dependent clotting factors |
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Alcohol intolerance is a side-effect of what? what is it?
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Cephalosporins
disulfiram-like reaction-- Disulfiram is an agent that inhibits alcohol dehydrogenase, causing an increase of acetaldehyde, the agent that causes hangovers |
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what causes the adverse side effects of cephalosporins? what drugs is it in?
*** |
Due to methylthiotetrazole (MTT) group
Cefotetan (2nd generation) Cefoperazone (3rd generation) |
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primary use for 1st generation cephalosporins? Specific drug?
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Prophylaxis of surgical procedures
(cefazolin) |
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primary clinical use for 2nd generation cephalosporins? 4
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UTIs,
soft tissue infections, bone infections, surgical prophylaxis SUBS |
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primary use for 3rd generation cephalosporin?
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Nosocomial G- infections ... often in combination with AGs
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1st gen cephalosporins are active against?
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G+ plus Proteus, E. coli, Klebsiella
(Pen G + PEcK) |
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Cefazolin used for
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surgical prophylaxis
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Cefoxitin Cefaclor Cefprozil
are what drugs |
2nd Generation
cephalosporin |
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spectrum of coverage for 2nd gen cephalosporins?
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G+ + H. influenza, Enterobacter, Neisseria, Proteus, E. coli, Klebsiella
(G+ HEN PEcK) |
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what is primarily used to treat sinusitis, bronchitis, otitis media
lower respiratory tract infections ? |
2nd gen cephalosporins
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Allergic reactions
Blood dyscrasias (anemia, eosinophilia) Pseudomembranous colitis are side effects of what? |
2nd Generation Cephalosporins
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