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EXAM 6 > Antibiotics > Flashcards

Antibiotics Flashcards

1
Q

selective toxicity

A

want a very high therapeutic index

LD50/ED50

hurt bacteria not host

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2
Q

DNA replication abx

A

quinolones

binds to DNA gyrase (which helps unwind DNA while it’s replicating) - allows it to make breaks but not close them- kills

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3
Q

RNA synthesis abx

A

Rifampin

binds to RNA polymerase and revents from transcription

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4
Q

Protein synthesis

A

tetracyclines, macrolides, aninoclygosides

binds to subunit of ribosome (large or small) ad inhibits binding of tRNA

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5
Q

metabolism

A

sulfonamides

inhibit tetrahydropfolate synthesis - bacteria has to make FH4

binds way more tightly to bac enzyme then human enzyme

structural mimicry or so can’t recycle into FH4

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6
Q

cell wall synthesis

A

beta lactams, vancomycin

inhibit transpeptidase (second step in linking of polypeptides)

beta lactam ring = mimicry - binds to beta lactam - formed irreversibly and stuck so crosslinking of cell wall can’t happen

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7
Q

Vancomycin

A

cell wall synthesis blocker but blocks transglycolase and transpeptidase

only kills cells that are growing

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8
Q

bacteriostatic v bacteriocidal

A

bacteriostatic - arrest cell growth so immune system can kick in and control

bacteriocidal - don’t want to wait for immune - kill!

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9
Q

efflux pump

A

tetracycline

pumps drug out of cell so it can’t have an effect

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10
Q

beta-lactamase

A

made by bacteria - breaks important bond in beta-lactam so it is ineffective

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11
Q

vancomycin-resistant bacteria

A

sub D-lactate for terminal D-ala

vancomycin can’t bind!! ineffective

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12
Q

clavulanate

A

inactivates beta lactamase - looks like beta lactam and inactivates the enzyme so beta-lactam can work

synergistic activity

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13
Q

concentration dependent killing

A

higher dosee kill better!

high dose extended intervals - high peak concentration

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14
Q

time dependent killing

A

no persistent effects

dose frequently (or continuously)

beta lactams!

try to exceed MIC for 50% of interval

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15
Q

when bacteriocidal

A

in immune compromised - can’t take over to kill!

immune priveleged sites (meningitis)

non-removable sources - device relate infection (endocarditis)

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16
Q

Combination therapy

A

synergy - enterococcus! PCN (upsets cell membrane) and aniglycoside (only works if gets in)

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17
Q

General Beta-Lactams

A

i.e. PCN

any gram

time dependent

bind PBP, prevent crosslinking of peptidoglycans, lead to lysis

majorty eliminated by kidney

allergy (PCN - hypersensitivity - cross to other beta lactams, use something else unless syphillus then desensitize)

gallstones with cetriaxone!

pregnant woman with syphillus and pcn allergy

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18
Q

Penicillin G

A

Natural Penicillin

gram positive, narrowest

strep A!

normal beta-lactam action

seizures at high dose

narrow spectrum - strep (a and b) enterococcus, psirochetes, s. pneumonae (community)

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19
Q

aminopenicillin

A

ampicillin, amoxicillin

covers same as natural PCN + gram negatives/enterococci- slightly broader! (adds e. coli, H. influenze, enterococcus)

normal beta lactam activity

20
Q

Aminopenicillin adverse rxn

A

rash especially with EBV! not IgE mediated

21
Q

Penicillinase-Resistant Penicilllins

A

Oxacillin, Nafcillin

same as PCN G but adds MSSA (s. aureus)

normal beta lactam but resistant to beta-lactamase (beta lactam ring can’t be opened)

22
Q

Penicillinase-Resistant Penicillin adverse rxn

A

interstitial nephritis

(nafcillin, nephritis)

23
Q

Extended spectrum penicillins

A

piperacillin

broadest and best gram negative coverage, includes psuedamonas aeruginosa

hospital acquired pneumonia!

NOT s. aureus when used alone, needs beta-lactamase inhibitor for full spectrum not MSSA!

24
Q

beta-lactamase inhibitor combinations

A

Augmentin (amox-clav)

beta-lactamases = PBPs but smaller

extend coverage to beta-lactamase bacteria, very broad

NEED to restore activity for MSSA, psudomonas aeruginosa

bind irreversibly to beta lactamases - restore activity of abx to some organisms

if symptoms don’t go away completely with abx

25
First generation cephalosporin
cephazolin beta lactam time dependent surgical prophylaxis (strep and staph) they earlier the generation, the greater the gram positive activity!! bset gram positive
26
second generation cephalosporin
beta lactam respiratory tract infections better gram negative, less gram positive
27
third generation cephalosporin
ceftriaxone (TRI - 3rd!) best for gram negative, worst for gram positive CA-pneumonia, Lyme, meningitis time dep beta lactam
28
fourth generation cephalosporin
Cefepime very broad - good for all bac including gram neg and pseudomonas (HA-gram neg) resistance in hospital acquired bugs resistance to beta-lactamases! increasing generation - more resistance to beta lactamase
29
Carbapenems
broadest spectrum antibiotic!! beta lactam serious noscomial infections and broad resistance! most stable to beta-lactamases toxic: CNS toxicity
30
Monobactam
Aztreonam No = monobacrim, No allergic rxn, Negative (gram neg) no anaplylaxis in PCN allergic patients (no ring - only side chains) treatment of gram negative infections in PCN allergic patients
31
PCN allergy
hypersensitivity - IgE to metabolites after beta-lactam ring opens - cross reactivity desensitization - if allergy and can't uses second line, administer gradually increasing doses in ICU i.e. syphillis during pregnancy, syphilitic meningitis in HIV-infected patients
32
Vancomycin
very braod spectrum go to for MRSA and coagulase negative staph, enterococci binds D-ala and prevents crosslinking (if D-lactate - resistance)
33
Vancomycin adverse rxns
red person syndrome non-immune release of hsitamine treat w antihistamine and infuse more slowly
34
Aminoglycosides
serious gram negative, pseudomonas post antibiotic effect and concentration dependent killing - give less (less toxic) binds ribo sunbunit (synergy with beta-lactams) major toxiciity: nephrotoxicity - acute! NEs: NEphrotoxicity (severe) so you NEver wanna use it, and it's used for gram NEgative, in syNErgy (with beta-lactam antibiotics)
35
Macrolides
erythromycin, asithrymycin CA-pneumonia, non-gonococcal urethritis (chlamydia) binds ribo subunit toxicity: QT prolongation
36
Clindamycin
Anaerobic infections (lung, dental, intraabdominal) ## Footnote Antitoxin effect - used to make sure bacteria that produce toxins such as anthrax have protein synthesis inhibited before lysis adverse: diarrhea, c. diff excellent bioavailablitiy
37
Tetracyclines
spirochetes (lyme, syphillis), atypical pneumonia bind ribosome bind divalent cations - don't take with dairy bacteriostatic!! efflux pump
38
Tigecycline
multiply drug resistant gram negative (no psuedomonas) added activity against MRSA! "super tetracycline"! same but no efflux pump activity
39
Daptomycin
serious s. aureus (do NOT use for pneumonia! inactivated by surfactant) MRSA, VISA (i.e. resistant bacteria) gram positive rapidly bacteriocidal, depolarizes membrane toxic: myopathy (muscle pain) Daptomycin starts with D, so mechanism is disrupts/depolarizes membrane. Also it's rapidly bacteriocidal and toxic, so it's the DAP ZAP
40
Oxazolidinones
Linezolid bacteriostatic infections due to resistant gram pos! MRSA and VRE adverse: decreased plately touts, serotonin syndrome
41
Fluoroquinolones
complicated UTIs and prostatitis, respiratory tract, bone and joint inhibits DNA rep (ds break) Arthritis/Tendonitis, Can delay detection of TB, should not be used in children or during pregnancy, Only antibiotic class with a U in the name, so Urogenital (UG)
42
Quinolones adverse events
prolonged QT interval, arthritis/tendonitis, GI - c. diff
43
Metronidazole
anaerobic, c.diff concentration dependent - 100% bioavailability inhibits DNA replication Disulfira - NO ALCOHOL
44
Trimethoprim-Sulfamethoxazole
UTIs, prostatitis, Pneumocystic jiroveci pneumonia and prophylaxis, CA-MRSA prophylaxis is AIDS pts, immunocompromised toxicities: skin rash
45
Polymyxin
"last resort) for mult resistant gram neg - esp psuedomonas detergent - dirupts bac cell membrane phospholipids Toxicities: kidneys and nervous system POLYmyxin = for gram negative, when POLY resistance to all other antibiotics

EXAM 6 (4 decks)

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