antibiotics Flashcards

1
Q

Which drugs block cell wall synthesis by inhibition of peptidoglycan cross-linking

A

Penicillin, methicillin, ampicillin, piperacillin, cephalosporins, aztreonam, imipenem

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2
Q

which drugs block peptidoglycan synthesis

A

Bacitracin, vancomycin

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3
Q

which drugs block nucleotide synthesis by inhibiting folic acid synthesis (involved in methylation)

A

Sulfonamides, Trimethoprim

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4
Q

which drugs block DNA topoisomerase

A

Fluoroquinolones

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5
Q

which drugs block mRNA synthesis

A

Rifampin

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6
Q

which drug damages DNA

A

Metronidazole

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7
Q

Which drugs block protein synthesis at 50S ribosomal subunit

A

Chloramphenicol, macrolides, clindamycin, streptogramins (quinupristin, dalfopristin), linezolid

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8
Q

Which drugs block protein synthesis at 30S ribosomal subunit

A

Aminoglycosides, Tetracyclines

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9
Q

Name types of penicillins

A

Penicillin G (IV and IM & Penicillin V (oral)

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10
Q

Mechanism of penicillin

A
  • binds penicillin-binding protein (pbp; transpeptidases– block transpeptidases cross-linking of peptidoglycan– active autolytic enzymes
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11
Q

Clinical use of penicillin

A
  • mostly for gram(+) organisms (S. pneumo, S. pyogenes, Actinomyces)– N. meningitidis, T.pallidum, Syphilis
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12
Q

What are penicillins bactericidal for

A
  • gram (+) cocci- gram (+) rods- gram (-) cocci- spirochetes
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13
Q

Penicillin toxicity

A

NAME?

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14
Q

Penicillin resistance caused by

A

beta lactamases cleave beta lactam ring

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15
Q

Name the narrow spectrum penicillins

A

Oxacillin, nafcillin, dicloxacillin

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16
Q

Mechanism of narrow spectrum penicillins

A

oxacillin, nafcillin, dicloxacillin- same as penicillin (binds PBP, block transpeptidases cross-linking peptidoglycans)

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17
Q

Narrow spectrum penicillins – characteristics

A

oxacillin, nafcillin, dicloxacillin- penicillinase resistant because bulky R group which blocks access of beta lactamase to beta lactam ring

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18
Q

clinical use of Narrow spectrum penicillins

A

oxacillin, nafcillin, dicloxacillin- S. aureus (except MRSA)

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19
Q

Why is MRSA resistant to narrow specrum penicillins?

A

oxacillin, nafcillin, dicloxacillin- because of altered PBP

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20
Q

Toxicity caused by narrow spectrum penicillins

A

oxacillin, nafcillin, dicloxacillin - - hypersensitivity reactions- - interstitial nephritis

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21
Q

What is the use of nafcillin

A

naf for staph

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22
Q

Name wide spectrum penicillins

A

ampicillin, amoxicillin (aminopenicillins)

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23
Q

Mechanism of wide spectrum penicillins

A

ampicillin, amoxicillin - same as penicillin- binds PBP, block transpeptidases cross-linking peptidoglycans

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24
Q

Difference between narrow and wide spectrum penicillins

A

ampicillin, amoxicillin vs nafcillin, oxacillin, dicloxacillin - wide spectrum are penicillinase sensitive whereas narrow spectrum are penicillinase resistant

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25
Q

What are wide spectrum penicillins commonly combined with and why

A

ampicillin, amoxicillin -clavulanic acid to protect against beta lactamase

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26
Q

What is the difference between amoxicillin and ampicillin

A

amoxicillin has more oral bioavailability than ampicillin

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27
Q

what are the uses for wide spectrum penicillins

A

Haemophilus influenzae;E. coli;Listeria monocytogenes; Proteus mirabilis; Salmonella; Shigella; enterococci; “ampicillin/amoxicillin HELPSS kill enterococci”

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28
Q

toxicity caused by wide spectrum penicillins

A

hypersensitivity, ampicillin rash, pseudomembranous colitis

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29
Q

resistance to wide spectrum penicillins caused by

A

beta lactamases cleave beta lactam ring

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30
Q

Name extended spectrum penicillins

A

ticarcillin, piperacillin

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31
Q

what is the mechanism of extended spectrum penicillins

A

Ticarcillin, piperacillin - same as penicillin (bind PBP, block transpeptidases cross-linking peptidoglycan)

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32
Q

use of extended spectrum penicillins

A

ticarcillin, piperacillin - antipseudomonal (Pseudomonas spp.) - gram (-) rods

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33
Q

limitations of extended spectrum penicillins

A

susceptible to penicillinase, so use with clavulanic acid

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34
Q

toxicity to extended spectrum penicillins

A

hypersensitivity

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35
Q

name beta lactamase inhibitors

A

NAME?

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36
Q

use of beta lactamase inhibitors

A

often used with penicillins to protect the antibiotic from destruction by beta lactamase (penicillinase)

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37
Q

Cephalosporins – mechanism

A

beta lactam drug that inhibits cell wall synthesis but are less susceptible to penicillinases

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38
Q

are cephalosporins bactericidal or bacteristatic

A

NAME?

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39
Q

name first generation cephalosporins

A

cefazolin, cephalexin

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40
Q

1st gen cephalosporins – use

A

cefazolin, cephalexin - gram (+) cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae - “PEcK”

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41
Q

common use of cefazolin

A

used prior to surgery to prevent S. aureus infection

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42
Q

2nd gen cephalosporins – names

A

cefoxitin, cefaclor, cefuroxime

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43
Q

2nd gen cephalosporins – use

A

cefoxitin, cefaclor, cefuroxime- gram (+) cocci- Haemophilus influenzae- Enterobacter aerogenes- Neisseria spp.- Proteus mirabilis- E. coli- Klebsiella pneumoniae- Serratia- “HEN PEcKS”

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44
Q

3rd gen cephalosporins – names

A

ceftriaxone, cefotaxime, ceftazidime

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45
Q

3rd gen cephalosporins – use

A

ceftriaxone, cefotaxime, ceftazidime - serious gram (-) infections resistant to other beta lactams

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46
Q

Use of ceftriaxone

A

meningitis and gonorrhea

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47
Q

use of ceftazidime

A

pseudomonas

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48
Q

4th gen cephalosporins – name

A

cefepime

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49
Q

4th gen cephalosporins – use

A

increased activity vs Pseudomonas and gram (+) organism

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50
Q

Name organisms typically not covered by cephalosporins + exception

A

LAME - Listeria - Atypicals (chlamydia, mycoplasma) - MRSA - Enterococci ; Exception: Ceftaroline covers MRSA

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51
Q

What is ceftaroline

A

the first “5th generation” cephalosporin

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52
Q

ceftaroline – use

A

broader Gram-positive spectrum of activity than all other cephalosporins

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53
Q

cephalosporin – toxicity

A

NAME?

54
Q

Aztreonam – mechanism

A

prevents peptidoglycan crosslinking by binding to PBP3

55
Q

Aztreonam – characteristics

A

NAME?

56
Q

Aztreonam – use in infection with

A
  • gram (-) rods ONLY - no activity against gram (+) or anaerobes
57
Q

Aztreonam – indicated for patients who

A

NAME?

58
Q

Carbapenems – names

A

imipenem, cilastatin, meropenem

59
Q

Imipenem – characteristics

A

broad-spectrum, beta-lactamase resistant carbapenem

60
Q

Cilastatin – mechanism

A

inhibitor of renal dehydropeptidase I

61
Q

Imipenem – restrictions

A

must always be administered with cilastatin to decrease inactivation of drug in renal tubules

62
Q

name newer carbapenems

A

ertapenem, doripenem

63
Q

carbapenem – uses

A
  • gram (+) cocci - gram (-) rods - anaerobes
64
Q

carbapenem – side effects

A

GI distress, skin rash, CNS toxicity (seizures) at high plasma levels

65
Q

Carbapenems – limitations

A

wide spectrum but significant side effects limit use to life-threatening infections or after other drugs have failed

66
Q

Carbapenems – which drug is exception to which limitations

A

meropenem has reduced risk of seizures and is stable to dehydropeptidase I

67
Q

Vancomycin - mechanism

A

inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors. is bactericidal

68
Q

Vancomycin – use

A
  • Gram (+) only - serious multidrug resistant organisms including MRSA, enterococci and C.diff (oral dose for pseudomembranous colitis)
69
Q

Vancomycin – toxicity

A

Red man syndrome – nephrotoxicity, ototoxicity, thrombophlebitis, diffuse flushing - well tollerated in general – does NOT have many problems

70
Q

what can prevent red man syndrome

A

pretreating with antihistamines and slow infusion rate

71
Q

What causes Vancomycin resistance

A

amino acid change of D-ala D-ala to D-ala D-lac

72
Q

protein synthesis inhibitors – mechanism

A

specifically target smaller bacterial ribosomes (70S made of 30S and 50S) leaving human 80S ribososmes alone

73
Q

Name 30S inhibitors and whether bactericidal or static

A

Aminoglycosides - cidal ; Tetracyclines - static

74
Q

Name 50S inhibitors and whether static or cidal

A

Chloramphenicol - static ; Clindamycin - static; Erythromycin (macrolides) - static ; Linezolid - variable ; “buy AT 30, CCEL at 50”

75
Q

additional mechanism of aminoglycosides

A

causes misreading of mRNA

76
Q

Aminoglycosides – names

A

Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin

77
Q

Aminoglycosides – mechanism

A

gentamycin, neomycin, amikacin, tobramycin, streptomycin - bactericidal, - inhibit formation of initiation complex - cause misreading of mRNA - Block translocation

78
Q

Aminoglycosides – limitations

A

require O2 so ineffective against anaerobes (aminO2glycosides)

79
Q

Aminoglycosides – use

A

gentamycin, neomycin, amikacin, tobramycin, streptomycin - gram (-) rod infections

80
Q

What are aminoglycosides used with

A

synergistic with beta-lactams

81
Q

Neomycin – use

A

bowel surgery

82
Q

Aminoglycosides – toxicity

A

Gentamycin, Neomycin, Tobramycin, Amikacin, Streptomycin - nephrotoxicity - neuromuscular blokade - ototoxicity - teratogen

83
Q

Aminoglycosides – what increases likelihood of nephrotoxicity

A

when used with cephalosporins

84
Q

Aminoglycosides – what increases likelihood of ototoxicity

A

when used with loop diuretics

85
Q

Aminoglycosides – resistance caused by

A

transferase enzymes that inactivate the drug by acetylation, phosphorylation or adenylation

86
Q

Tetracyclines – names

A

tetracycline, doxycycline, demeclocycline, minocycline

87
Q

demeclocycline – mechanism and use

A

ADH antagonist, acts as diuretic in SIAdh

88
Q

Tetracyclines – mechanism

A

tetracycline, doxycycline, demeclocycline, minocycline - bacteriostatic - binds 30S and prevents attachment of aminoacyl-tRNA

89
Q

Tetracycilnes – limitations

A

NAME?

90
Q

Doxycycline – limitation

A

fecally elimitinated and cannot be used in patients with renal failure

91
Q

Tetracycines – use

A

NAME?

92
Q

why are tetracyclines particularly helpful in rickettsia and chlamydia

A

it can accumulate intracellularly thus helpful for intracellular bugs

93
Q

Tetracycline – toxicity

A

NAME?

94
Q

Tetracycline – contraindication

A

pregnancy

95
Q

Tetracycline – resistance caused by

A

decreased uptake into cell or increased efflux out of cell caused by plasmid-encoded transport pumps

96
Q

Macrolides – names

A

azythromycin, clarithromycin, erythromycin

97
Q

Macrolides – mechanism

A

azythromycin, clarithromycin, erythromycin - inhibit protein synthesis by blocking translocation - binds 23S rRNA of the 50S subunit - bacteriostatic

98
Q

Macrolides – use

A

Azythromycin, clarithromycin, erythromycin - atypical pneumonias (mycoplasma, chamydia, legionella) - STDs (Chlamydia) - Gram (+) cocci (strep infections in patients allergic to penicillin)

99
Q

Macrolides – toxicity

A

MACRO; - Motility issues - Arrhythmia caused by prolonged QT - Cholestatic hepatitis (acute) - Rash - eOsinophilia

100
Q

Macrolides – drug interactions

A

increase serum concentration of theophyllines, oral anticoags

101
Q

Macrolides – indication

A

pregnant women ; “macrolides for pregnant wives”

102
Q

Macrolides – resistance caused by

A

methylation of 23S rRNA binding site

103
Q

Chloramphenicol – mechanism

A

block peptidyltransferase at 50S ribosomal subunit ; - bacteriostatic

104
Q

Chloramphenicol – use

A

meningitis caused by - H. influenzae - neisseria meningitides - Strep. pneumoniae

105
Q

Chloramphenicol – toxicity

A
  • Anemia (dose dependent) - aplastic anemia (dose independent) - Gray baby syndrome (in premature infants because they lack liver UDP-glucuronyl transferase)
106
Q

Chloramphenicol – resistance

A

NAME?

107
Q

Clindamycin – mechanism

A
  • blocks peptide transfer (transpeptidation) at 50S ribosomal subunit - bacteriostatic
108
Q

Clindamycin – use

A

NAME?

109
Q

Clindamycin vs metronidazole

A

note!! treats anaerobes above the diaphragm vs. metronidazole which treats anaerobic infections below the diaphragm

110
Q

Clindamycin – toxicity

A

pseudomembranous colitis (C.difficile overgrowth), fever diarrhea

111
Q

Sulfonamides – names

A

sulfamethoxazole (SMX), sulfisoxazole, sulfadiazine

112
Q

Sulfonamides – mechanism

A

NAME?

113
Q

Sulfonamides – use

A
  • gram (+) - gram (-) - Nocardia - Chlamydia
114
Q

Sulfonamides – how to treat UTI

A

triple sulfas or SMX for simple UTI

115
Q

Sulfonamides – toxicity

A

NAME?

116
Q

Sulfonamides – drug interactions

A
  • displace other drugs from albumin (eg. warfarin)!!!
117
Q

Sulfonamides – resistance

A

NAME?

118
Q

Trimethoprim – mechanism

A

inhibits bacterial dihydrofolate reductase - bacteriostatic

119
Q

trimethoprim – use + combos

A
  • combined with sulfonamides (trimethoprim-sulfamethoxazole [TMP-SMX]) - cause sequential sequential block of folate synthesis - combo used for UTIs, Shigella, Salmonella, Pneumocystis jirovecci pneumonia (Rx and PPx)
120
Q

Fluoroquinolones – names

A

NAME?

121
Q

Quinolones – name

A

nalidixic acid

122
Q

Fluoroquinolones – mechanism

A

NAME?

123
Q

Fluoroquinolones – contraindications

A

NAME?

124
Q

fluoroquinolones – use

A
  • gram (-) rods of urinary and GI tracts (includes pseudomonas) - Neisseria - some gram (+)
125
Q

Fluoroquinolones – toxicity

A
  • GI upset, superinfections, skin rashes, headache, dizziness - less commonly: cause tendonitis, tendon rupture, leg cramps, myalgias - prolonged QT interval - tendon rupture in people >60 years and in people using prednisone– “fluoroquinoLONES hurt attachments in your BONES”
126
Q

Fluoroquinolones – resistance caused by

A

NAME?

127
Q

Metronidazole – mechanism

A

forms free radical toxic metabolites in the bacterial cell that damage DNA. - bactericidal - antiprotozoal

128
Q

Metronidazole – use

A

treats: - Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis - Anaerobes (bacteroides, C. difficult) -h.Pylori (if used with PPI and clarythromycin for thriple therapy)– “GET GAP on the Metro with Metronidazole!”

129
Q

Metronidazole vs Clindamycin

A

metronidazole treats anaerobic infections below the diaphragm vs. clindamycin (anaerobic infections above the diaphragm)

130
Q

metronidazole – toxicity

A

disulfiram-like rxn with alcohol – headache – metalic taste