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PHA 550 > Antibacterials > Flashcards

Antibacterials Flashcards

1
Q

Four Mechanisms of Actions of Antibacterials

A
  1. inhibitors of cell wall synthesis
  2. inhibitors of translation and transcription
  3. inhibition of DNA syntheses and integrity
  4. inhibitors of folate synthesis and function
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2
Q

Inhibitors of Cell Wall Synthesis

A

beta lactams penicillins

cephalosporins

glycopeptides: vancomycin

TB medications

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3
Q

Inhibitors of Translation/Transcription

A

tetracyclines

macrolides

clindamycin

oxazolidinones: linezolid

aminoglycosides and spectinomycin

TB medications

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4
Q

Inhibition of DNA syntheses and integrity/inhibitors of folate synthesis and function

A

sulfonamides, trimethoprim

quinolones

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5
Q

Bactericidal

A

mechanism is generally inhibit cell wall synthesis

time dependent killing

concentration dependent killing

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6
Q

Time Dependent Killing

A

serum level above MIC

beta lactams, vancomycin

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7
Q

Concentration Dependent Killing

A

higher drug concentration determines rate and extent of killing

aminoglycosides, quinolones

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8
Q

Bacteriostatic

A

mechanism is generally inhibition of protein synthesis

tetracyclines, macrolides, sulfonamides

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9
Q

Postantibiotic Effect

A

persistent suppression of bacterial growth after limited exposure to an antimicrobial agent

antibiotic level falls below MIC

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10
Q

Postantibiotic Effect: Proposed Mechanisms

A

slow recovery after reversible non lethal damage to cell structures

persistence of the drug at the binding site

need to synthesize new enzymes before microorganism growth can resume

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11
Q

Penicillin: narrow spectrum

A

Penicillinase susceptible:

  • PCN G
  • PCN VK

Penicillinase resistant:

  • nafcillin
  • oxacillin
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12
Q

Penicillin: wider spectrum

A

+/- penicillinase inhibitor

  • ampicillin
  • amoxicillin
  • piperacillin
  • ticarcillin
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13
Q

What additional microorganisms are covered by amoxicillin but NOT penicillin?

A

H influenza
M catarrhalis
S aureus
Strept

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14
Q

Penicillin: PK

A

rapid renal elimination

some biliary clearance (ampicillin, nafcillin)
-concern for newborns

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15
Q

Penicillin: ADE

A

hypersensitivity rxn

maculopapular rash (ampicllin)

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16
Q

Penicillin: activity spectrum (narrow and wider)

A

Narrow:

  • streptococcal infections
  • staphlococcal infections
  • meningococcal infections
  • syphilis

Wider:
-gram negative bacteria

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17
Q

Cephalosporins: first generation

A

cephalexin

activity:

  • skin
  • soft tissue
  • UTI
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18
Q

Cephalosporins: second generation

A

cefotetan
cefoxitin
cefuroxime

activity:

  • S pneumoniae
  • H influenza
  • B fragilis (cefotetan)
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19
Q

Cephalosporins: third generation

A

ceftriaxone
cefixime
cefotaxime
ceftazidime

activity:
- pneumonia
- meningitis
- gonorrhea
- broad activity(beta lactamase stable)

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20
Q

Cephalosporins: fourth generation

A

cefipime

activity:
-pseudomonas

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21
Q

Cephalosporins: fifth generation

A

ceftaroline

activity:

  • skin
  • soft tissue
  • CA pneumonia
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22
Q

Cephalosporins: PK

A

older: oral
newer: IV

renal elimination

THIRD GENERATION ENTER CNS

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23
Q

Cephalosporins: ADEs

A

hypersensitivity reactions

assume complete cross reactivity bt cephalosporins

1st generation: partial cross reactivity with PCNs

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24
Q

What cephalosporin is not given to newborns?

A

cetriaxone

-displaces bilirubin

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25
Q

Carbapenem

A

other beta lactam

imipenem-cilastatin (primaxin)
doripenem
meropenem
ertapenem

broad spectrum activity

  • PRSP (not MRSA)
  • gram negative rods
  • pseudomonas
ADEs: 
CNS effects (confusion, seizures)
26
Q

Monobactam

A

other beta lactam

aztreonam

no cross reactivity with beta lactams

activity:
gram negative bacteria
-klebsiella
-pseudomonas
-serratia

ADEs:
CNS (HA, vertigo)

27
Q

Glycopeptides

A

vancomycin (MRSA, PRSP)

dalbavancin (skin)

oritavancin (skin)

telavancin (skin, HABP/VABP)

activity:
gram positive activity

28
Q

Glycopeptides: PK

A

parenteral for systemic infections

oral vancomycin for C difficile colitis

renal elimination

29
Q

Glycopeptides: toxicities

A

red neck/red man syndrome

  • erythematous rash on face, upper body
  • cause: infusion rate

nephrotoxicity (rare)

30
Q

Daptomycin

A

lipopeptide

PK: renal elimination

toxicity:
myopathy (weekly CPK/CK)

activity:
gram positive
-endocarditis, sepsis
-MSSA, MRSA

off label:

  • osteomyelitis
  • prosthetic joint infections
31
Q

Tetracycline (30S): agents

A

tetracycline
doxycycline
minocycline
tigecycline

32
Q

Tetracycline: activity spectrum

A 
anthrax
chlamydial
mycoplasma
rickettsiae (RMSF, typhus)
spirochetes (lyme disease, relapse fever, syphilis)
H pylori
33
Q

Tetracycline: uses

A

acne
CAP, bronchitis
lyme disease
periodontitis

off label:

  • cellulitis (CA MRSA)
  • acute bacterial rhinosinusitis
34
Q

Tetracycline: ADEs

A

GI upset

interaction with di and trivalent ions

deposition in developing bones and teeth***

photosensitivity

35
Q

Macrolide (50S): agents

A

erythromycin
azithromycin (Z pak)
clarithromycin

36
Q

Macrolide: ADEs

A

GI upset

hepatic dysfunction

QT elongation

CYP450 (NOT azithromycin)

37
Q

Macrolide: activity spectrum

A

CAP
pertussis
corynebacteria (diphtheria)
chlamydial

38
Q

Lincosamdie (50S)

A

clindamycin

activity:

  • skin infections
  • soft tissue infections
  • anaerobic infections

ADE:
C difficile colitis

39
Q

Chloramphenicol (50S): ADEs

A

-dose related (aplastic) anemia

-gray baby
syndrome

symptoms:

  • circulatory collapse
  • cyanosis
  • acidosis
  • abdominal distention
  • myocardial depression
  • coma
  • death

risks:

  • serum levels >50mcg/ml
  • patients with impaired renal/hepatic function
40
Q

Chloramphenicol: activity spectrum

A

serious infections (resistant to less toxic abx)

  • bacteroides
  • H influenza
  • N meningitides
  • salmonella
  • rickettsia

active against many vancomycin resistant enterococci

41
Q

Oxazolidinone

A

binds to 23S RNA of 50S subunit

agent: linezolid

activity:

  • MRSA
  • PRSP
  • VRE strains

ADEs:

  • dose related anemia
  • neuropathy
  • optic neuritis
  • serotonin syndrome with SSRIs
42
Q

Aminoglycoside (30S): agents

A 
gentamicin
tobramycin
amikacin
streptomycin
neomycin
43
Q

Aminoglycoside: activity spectrum

A

aerobic gram negative bacteria

H influenza

M catarrhalis

shigella

often used in combination with beta lactams

44
Q

Aminoglycoside: ADEs

A

nephrotoxicity
ototoxicity
neuromuscular blockade

45
Q

Antifolates: mechanism sulfonamide, trimethoprim

A

blockade of folic acid synthesis

sulfamethoxazole:

  • interferes with bacterial folic acid synthesis and growth
  • inhibition of dihydrofolic acid formation from para-aminonbenzoic acid

trimethoprim:

  • inhibits dihydrofolic acid reduction to tetrahydrofolate
  • sequential inhibition of enzymes of the folic acid pathway
46
Q

Antifolates: mechanism fluoroquinolones

A

interfere with bacterial DNA synthesis by inhibiting DNA gyrase

inhibits relaxation of supercoiled DNA

47
Q

Sulfonamides with Trimethoprim (Trimethoprim-sulfamethoxazole): activity spectrum

A 
UTI
traveler's diarrhea
respiratory infections
ear infections
sinus infections
P jiroveci pneumonia (HIV)
toxoplasmosis (HIV)
nocardiosis
MSSA/MRSA skin soft tissue infections
48
Q

Sulfonamides with Trimethoprim: ADEs

A

rash
fever
bone marrow suppression
hyperkalemia

AIDs patients:

  • neutropenia
  • stevens johnson syndrome
  • toxic epidermal necrolysis
49
Q

What stage of pregnancy should TMP/SMX be avoided?

A

first trimester

after 32 weeks

50
Q

Quinolones: agents

A

ciprofloxacin

levofloxacin

gatifloxacin

gemfloxacin

moxifloxacin

ofloxacin

51
Q

Quinolones: activity spectrum

A

urogenital infections
GI tract infections
bacterial conjunctivitis

52
Q

Ciprofloxacin, ofloxacin: activity spectrum

A

UTIs

53
Q

Levofloxacin, gemfloxain, moxifloxacin: activity spectrum

A

respiratory flouroquinolones

gram positive cocci

atypicals (chlamydia, mycoplasma)

54
Q

Quinolones: ADEs

A 
CNS effects (dizziness, HA)
tendinitis
peripheral neuropathy
neuromuscular blocking activity
QTc prolongation (levofloxacin, gemifloxacin, moxifloxacin)
55
Q

Quinolones: interaction

A

oral absorption impaired by cations (Ca, Mg, Al)

caution with use of class IA and III antiarrhythmic

56
Q

In what neuromuscular disease should quinolones be avoided?

A

MYASTHENIA GRAVIS

because they disrupt neuromuscular transmission

also be wary of macrolides

57
Q

Synergism

A

inhibitory/killing effects of 2+ antimicrobials used together are significantly greater than expected (than when used individually)

fourfold+ reduction in MIC or MBC of each drug

58
Q

Empiric Treatment

A

antimicrobial agent used before pathogen is identified for particular illness or susceptibility is known

59
Q

Guided Treatment

A

effective antimicrobial agent identified by susceptibility testing of infecting microorganism

60
Q

Before you prescribe…

A 
allergy/hx of ADEs
age 
pregnancy
metabolic/genetic variation
renal/hepatic function
concomitant drug therapy
concomitant disease states
61
Q

Antibiogram

A

report of susceptibility/resistance of pathogens to antibiotics

information about local resistance patterns

used to determine empiric treatment options

PHA 550 (26 decks)

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