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Flashcards in PDA antibacterials Deck (144):
1

What are infections where -cidal drugs have an advantage?

pts with compromised immune system
following in immune-competent pts:
-meningitis
-endocarditis
-deep bone infections
-artificial device implants

2

What type of antibacterials are preferred for patients with competent immune systems with meningitis, endocarditis, deep bone infections, and artificial device implants?

-cidal drugs

3

What is time dependent killing?

amount of time about the MIC

4

What is concentration-dependent kkilling?

peak concentration matters most

5

What does it mean when drugs are concentration and time dependent?

area under curve of concentration over time vs MIC

6

When do time-dependent killing drugs work on epople?

drugs work best when conc. exceeds 4 times the MIC for greater than 50% of total time

7

What are beta-lactams dependent on for killing with respect to MIC?

Time-dependent

8

What type of depedency do amingolycosides have for killing?

concentration dependent and have persistent effect when levels fall below MIC

9

What type of dependenccy do quinolones have for killiing?

concentration x time (area under curve)

10

Why do beta-lactams requrie more frequent dosing?

time dependent killers and they have a shorter half life

11

Where do penicillins have low penetration?

into the csf; although increases during meningitis

12

How are penicillins eliminated?

renally; by anion transport

13

What are the half lives of penicillins?

short 30 minutes to 3 hours

14

How is penicillin V taken?

orally

15

How is penicllin G taken?

IV/IM

16

What are the spectrum of peniclin V and penicillin G?

anaerobes (mainly gram positivie)
gram positive that are non-beta-lactamase producing
1st line for strep throat
very limited gram negative
-neisseria meningitidis
spirochetes
-syphillis

17

What penicillins are used for beta-lactamase positive staphylococci?

methicillin type drugs; ie oxacillin
MSSA(methicillin sensitive Staph aureus)

18

What is the spectrum for ampicillin and amoxicillin?

maitain gram postiive (Beta lactamase negative)
-enterococcus
expanded gram negative spectrum

19

What is the drug of choice for otitis media in otherwise healthy children?

high dose amoxicillin

20

What is amoxiciiln an althernate choice for in young children and pregnat/breat-feeding women?

Lyme disease

21

What are 2 important uses for ampicillin that amoxicillin doesnt?

meningitis (neisseria, listeria)
bc available by IV
GI infections;
esp Shigella
bc less abosrbed in orally more avaiable in GI tract

22

What two penicilins have an extended gram-negative spectrum?

ticarcillin and piperacillin

23

What is the spectrumf or ticarcillin?

retain some gram-pos activity
good for some anaerobes
gram neg spectrum extended to include psuedomonas aeruginosa

24

What is the spectrum for piperacillin?

gram negative spectrum like ticarcillin but also some pseudomonas and klebsiella
include those that are ticarcillin-resistant

25

How can one predict severe allergic reaction to penicillin?

pt history
PRE-PEN
-skin test; 90-95% reliable at identifying those at risk for severe allergic reaction

26

What are the side effects of penicillins?

fever
diarrhea(most common side effect)
enterocolitis (all anti-biotics can causet his due to C diff infection)
elevated liver enzymes
hemolytic anemia
seizures

27

What are some common properties of cephalosporins?

well distributed; although only 3rd gen reach CSF
majority require injection
same mechanism as penicillin

28

What is teh spectrum for 1st generation cephalosporins??

mostly gram positive spectrum
uncomplicated outpatient skin infections
surgical prophylaxis esp for skin flora

29

What are two cephalosporin 1st generation drugs?

cefazolin and cephalexin

30

What are two examples of second generation cephalosporins?

cefuroxime and cefoxitin

31

What is teh only second gen cephalosporin to penetrate CSF?

cefuroxime

32

What is cefuroxime used to treat?

best second for haemophilus but poor against enterics
good tolerance to many gram negative beta lactamases

33

What is cefotoxin used to treat?

similar to many second gen but also good for anaerobes including B. fragilis
good tolerance to many gram-neg beta lactamases

34

What are two 3rd generation cephalosporins?

ceftriaxone and ceftazidime

35

What cephalosporin is a very good choice for common types of menigitis?

ceftriaxone

36

What is the therapy of choice for gonorrhea?

ceftriaxone

37

What is ceftriaxone used to treat?

common types of meningitis
gonorrhea
sever lyme disease
typhoid fever
surgical prophylaxis GI tract surgery

38

What is the half life comparison between 3rd generation cephalosporins?

ceftriaxone long half life 6-9 hours and ceftazidime shorter half life 90 minutes

39

What is ceftazimide used to treat?

meningitis, brain abcess
pseudomonas aueruginosa esp those resistant ot aminoglycosides
poorest for gram positive

40

What is the most active 3rd gen cephalosoporin for psuedomonas aeruginosa?

ceftazidime

41

What is teh poorest 3rd gen cephalosoporin for gram positive?

ceftazidime

42

What is a fourth generation cephalosporin?

cefepime

43

What is teh half life of cefepime?

2 hours

44

What is the spectrum of cefepime?

similar to ceftazidime except more resistant to inducible chromsomally endoced type 1 beta lactamases so covers mroe gram negative strain

45

What is cefepime used to treat

empirical treatment of serious inpatient infections where both gram positive and gram negative etiologies are possible

46

What are cephalosporins asa whole bad at treating?

camplobacter
legionella
C. Diff
listeria
Acinetobacter
enterococcus
penicillin resistant strep pneumoniae
MRSA

47

How are cephalosporins excreted?

Renally: GFR and anion secretion

48

What are teh allergic reactions of cephalosporins?

2-10% ( 1-20% pts cross react with penicilin)

49

What are teh side effects for sephalosporins?

allergic rxns
GI issues-generational differences
hepatocellular damage

50

What do extended spectrum Beta-lactamases inactivate?

penicillins as well as drugs considered beta lactamase resistant such as 3rd gen cephalosporins and monobactams

51

What are the treatment of choice for ESBL (extended spectrum beta lactamase) organisms?

carbapenems

52

What is the spectrum of imipenem?

broad spepctrum
gram pos and gram negative
resistant to most beta lactamases including ESBLs

53

What is imipenem not for?

C. diff, MRSA, Enterococcoccus faecium, some psuedomonas, stenophomonas

54

What class is imipenem?

carbapenem

55

What is imipenem used for therapeutically?

ill-defined infections
mixed infections
non-responsive or resistant to other drugs (ESBLs)

56

Why is imipenem given with cilastatin?

to prevent hydrolysis by renal dipeptidases

57

What are teh side effects of imipenem?

allergic rxns
seizures, dizziness, confusion
nausea, vomitin, diarrhea, pseudomembranous colitis, superinfection
thrombophlebitis

58

What is aztrenoam used to treat?

gram negative aerobic rods resistant to many beta lactamases

59

Does aztreonam have allergic cross-reactions with beta-lactams?

no

60

What are the side effects of aztreonam?

seizures, anaphylaxis, transient EKG changes
-GI issues
-hepatiits, jaudice, confusion

61

What is hte mechanism of action of vancomycin?

binds to free carboxl end of D-ala-Dala of the pentapetptide interferes with cross--linking of petidoglycan chain

62

What is vancomycin used to treat?

gram positives only
staph, incl MRSA
strep pneuomniae; hemolytic strep
enterococcus (20-30% resistant VRE)
C. dif enterocolitis

63

How is vancomycin administered?

IV for systemic infection
limited pen into CSF
oral for C. diff eneteroclitis

64

How is vanocmycin used to treat meningitis?

poor pen without inflamed meninges so used as a second line for cephalosporin resistant by combining 3rd gen cephalosporin and vancomycin together

65

What are the side effects of vancomycin?

nephrotoxicity
red man syndrome
ototoxicity
phlebitis
hypersensitivity, skin rashes, neutropenia

66

What is the use of fosfomycin?

uncomplicated UTIs caused by E. coli and enterococcus

67

What are the side effects of fosfomycin?

headache, diarrhea, nausea, vaginitis
dizziness, rash

68

What is the mechanism of bacitracin?

interferes with cell wall syntehsis by interfereing with carrier that moves early wall components through membrane

69

What is bacitracin used for?

topical only and used only against the gram positive spectrum

70

What is the side effect of bacitracin?

allergic dermatitis

71

What are drugs that target cell membrane?

polmyxin B and E
daptomycin

72

What is the mechanism of polymyxin B?

branched chain decapeptides; act as cationic detergents taht binds LPS in outer membrane of gram negatives

73

What are the side effects of polymyxin B?

topical use-few probelms, allergies
systemic use-potential for serious nephrotoxicity and neurotoxicity

74

What is the mechanism of daptomycin?

binds to bacterial cytoplasmic membrane causing rapid membrane depolarization
stops essential metabolic and catabolic steps
rapidly bactericidal

75

What is the spectrum of daptomycin?

gram positive spectrum
no cross resistance

76

What is the use of daptomycin?

for complicated skin and skin structure infections
MRSA
Streptococcus
Enterococcus (vancomycin-susceptile only)
bacteremia
not for pneumonia

77

What are the side effects of daptomycin?

nausea, diarrhea, GI flora alterations
including C. Diff enterocolitis
muscle pain and weakness
fever, headache, rash, dizziness, injection site rxn

78

What is the mechanism of action of quinolones?

inhibits alpha and possibly beta subunit of DNA gyrase, thereby interfering with control of DNA winding
bactericidal

79

How is killing by quinolones best predicted?

AUC24/MIC
more frequent doses
more drug per dose
longer half life

80

What is the norfloxacin used for?

prototype quinolone for urinary infections
limited use at other sites

81

What is ciprofloxacin used for?

useful for infections at many sites
UTI
infectious diarrhea
bone and joint infections
skin infections
not best choice for gram positive infections
chlamydia
haemophilus
anthrax

82

What is better against gram positive than cirpofloxacin used for?

moxifloxacin and levofloxacin

83

Quinolones administered how?

oral some also IV

84

How is quinolones distributed?

many fluorinated drugs are well-distributed
some and the nonfluorinated agents achieve therapeutic concentration onsly in urinary tract

85

What are the quinolones side effects?

nausea, vomitting, abdominal paiin
rare seizure
dizziness, headache, restlesness, depression
rashes, some serious potentially fatal
EKG iregullariteies, arrythmias
peripheral neuropathy; rapid onset
children cartilage damage cautioned
precautions those with seizure disorder and pregnancy
arthropathy-tendon rupture

86

What is the mechanism of nitrofurantoin?

itroreductase enzyme converts tehse drugs to reactive compounts whch ccan damage DNA

87

What does nitrofurantoi treat?

UTI lower only not renal

88

What are teh side effects of nitrofurantoin?

nausea, vomiting, diarrhea
hypersensitivity, fever, chills
peripheral neuropathy
acute and chronic pulmonary reaction
acute and chronic liver damage
granulocytopenia, leukopenia, megaloblatic anemia
acute hemolytic anemai

89

What is the mechanism of rifampin?

binds to and inhibits RNA pollymerase Beta
inhibits RNA synteshis
bacteriacidal

90

What is rifampin used for?

tuberculosis
meningitis prophylaxis
difficult infections

91

Wha are the side effects of rifampin?

serious hepatotoxicity
strongly induces many other enzymes including CYP3A
orange color to excrement
may others

92

What is the mechanism of fidaxomicin?

non competitive inhibitor of RNA polymerase

93

What is fidaxomicin used for?

clostridium dif infxn; 3rd line
bacteria cidal

94

What is the spectrum of fidaxomicin?

narrow gram pos mainly clostridium
oral admin, poorly absorbed
limited impact on normal GI flora

95

What are fidaxomicin side effects?

GI upset, GI bleed, neutropenia

96

What is the mechanism of action of metronidazole?

anaerobes reduce the nitro group resuting produc damages and disrrupts DNA
bacteriacidal

97

What are the uses of metronidazole?

anaerobes
C. diff enterocolitis
H. pylori combo therapy
bacterial vaginosis

98

What are the side effects of metronidazole?

nausea, vomiting, anorexia, diarrhea
transient leukopenia, neutropenia
thrombophlebitis after IV infusion
bacteria and fungal superinfection

99

Aminoglycosides are unique how?

only protein synthesis inhibitors that are bactericidal

100

What is teh mechanism of aminoglycosides?

transported into bacteria by energy-requirng aerobic procesc
bind to several ribosomal sites; stop initiation, cause mRNA misreading

101

What is the primary use of aminoglycosides?

primarily for gram negative aerobic bacilli
poor activity against anaerobes

102

How do you use aminoglycosides with gram positive bacteria?

cell wall inhibitors plus aminoglycosides lead to increased permeability and death of aminoglycosides

103

Aminoglycosides have post-antibiotic effect?

sustained activity for several hours after aminoglycoside concentraion ahd dropped below effective levels
concentration dependent killing

104

Aminoglycosides are restricted to what type of infections?

serious infections

105

What are teh three aminoglycosides?

gentamicin, tobramycin, amikacin

106

What ist he choice agent for gentamicin and tobramycin resistant straing?

amikacin

107

What are the two classic side effects of aminoglycoides?

nephrotoxicity-mostly reversible
ototoxicity-mostly irreversible
neuromuscular blockade-less common; associated with intraabdominal infection

108

Tetracyclines are what type of mechanism?

transported into cells by protein carrier binds aminoacyl-tRNA to 30S ribosomal subunit

109

What is teh most common for of resistance to tetracyclines?

drug efflux pumps, resistance to one tetracycline implies resistance to all

110

Use of tetracycline is the preffered agent for what?

unusual bugs
rickettsia
lyme disease
chlamdia, mycoplasma, ureaplasma(atypical)
chancroid (haemophilus ducreyi)

111

What are the two tetracyline examples?

doxycycline and minocycline

112

What is doxycycline used for?

alternative for penG-sens syphilis
uncomplicated N. gonorrheae

113

What is unique about doxycycline among tetracyclines?

has the least affinity for calcium

114

Binding calcium does what to tetracycline?

inhibits it's absorption

115

What are the side efffects of tetracycline?

GI disturbance
photosensitization
cadida infection
teeth discoloration- avoid use in you children
contraindicated in pregnancy

116

Tigecycline is used when?

increased risk of death makes it a last line drug when nothing else is working

117

Chloramphenicol has what mechanism of action?

binds 50S subunits to prevent protein use

118

Chloramphenicol has what major side effect and used for what?

very serious can result in bone marrow suppression
alternative in those with serious cephalosporin meningitis
brain abcesses (often anaerobes)

119

What are the major side effects of chloramphenicol?

Gray baby
bone marrow suppression
-fatal aplastic anemia (1 in 30000)
optic neuritis and blindness

120

What are the macrolides?

erythromycin, clarithromycin, azithromycin

121

What is the mechanism of macrolides?

bind 50S subunit and blocks translocation

122

What is erythromycin used for?

primarily against gram positive
2nd line against strep in allergic
also effective against atypical bugs
-mycoplasma, chlamydia, brdetella, legionella

123

What is erythromycin side effects?

rapid vomitting and nausea from enhacned GI motility
inhibits CyP3A metabolism
increased risk of arrythmias and cardiac arrest
-doubles risk on its own
5 fold on other CYP3A inhibitors

124

What is Clarithromycin role?

most expensive macrolide; similar mechanism
also some CV risk
prolongs QT interval
but less GI motility, wider antibacterial spectrum

125

What is the use of clarithromycin?

same as erythromycin plus:
haemophilus influenzae, moraaxella
pneicillin resistant strep pneuoniae
atypical mycobacteria
liscened for heliobacter pylori
3 drug combos are becoming standard

126

Heliobacter approved eradication include what?

combination with 2 antibiotcs + acid blocker most efective combination

127

What is the role of azithromycin

very common for outpatient respiratory tract infections
also genita infections-chlamydia and 2nd line for N. gonorrhea

128

Azithromycin has what adverse reactions?

fewer
still QT prolongation
fewer effects on CYP3A4

129

What is clindamycin mechanism of action?

binds to 50S ribosomal subunit

130

What is clindamycin famous for?

causing C. diff infections

131

What is the use for clindamycin?

Strep and MSSA (gram pos cocci)
suppresses bacterial toxin production
many anaerobes including bacteroides flragiles

132

What are the side effects of clindamycin?

liver damage
colitis
GI problems

133

What is the mechanism of linezolid?

binds to 50S ribosomal subunit and interferes with formation of 70S initiation complex

134

Linezolid is used for what?

gram positive spectrum
Vancomycin resistant Enterococcus
Staph Aureus including MRSA
Strep
Nosocomial pneuomniae

135

What are the side effects of linezolid?

non-selective inhibitor of MAO
diarrhea, eneterocolitis
headache, nausea/vomiting
bone marrow suppresion

136

What are the anti-folates?

inhibit folate synthesis
sulfamethoxazole
sulfadiazine
trimethoprim

137

What is mechanism of action of sulfonamides?

competitive analogs of p-aminobenzoic acid, a precursor in folate synthesis

138

Sulfonamides are used how?

wide spectrum but high resistance
used in combination with others

139

What is silver sulfadiazine used for?

used topically for infection prevention in burn pts
large amount of its effect is silver

140

What are the side effects of sulfonamides?

hypersensitivity
sunlight makes rashes worse
renal damage (crystalluria)
potentiate actions of other drugs
inhibit CYP2C9 therefore ave an effect on warfarin

141

Sulfonamides plus trimethorpim has waht sort of effect

-cidal effect; unusual bc its two statics

142

what is trimethorprim used for?

in combo wit sulfamethoxazole
used for uncomplicated UTIs
-E.coli and coagulase negative staph
upper respiratory tract, ear infections
GI infections
1st line in pneumocytis jiroveci

143

What are the side effects of the TMP/SMX side effects?

all of the sulfa side effects
bone marrow suppression
GI effects

144

What is one common use of empiric therapy?

uncomplicated cstitis in nonpregnant women