Exam 1: Antibiotics Flashcards

1
Q

1st Generation Penicillins

A

Penicillin G (IV), Penicillin VK (PO)

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2
Q

structural analog of D-Ala D-Ala is ____

A

B-lactam drugs

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3
Q

Penicillin pharmacokinetics

A

inactivated by gastric acid
small Vd, short half life
wide distribution but poor CNS penetration
renal secretion

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4
Q

beta lactam mechanisms of resistance

A
1 - physical barrier
2 - mutant porin
3 - efflux pump
4 - beta-lactamases
5 - mutant peptidoglycan transpeptidase (PBP- 2a present in MRSA, resistant to essentially all B-lactams)
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5
Q

Penicillin adverse effects

A

low direct toxicity
kills GI bugs –>Cdiff
CNS tremors or convulsion
hypersensitivity

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6
Q

2nd Generation Beta Lactams

A

Nafcillin (IV), Dicloxacillin (PO QID), Methicillin.

Penicillinase resistant

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7
Q

Nafcillin pharmacokinetics

A

erratic oral absorption so give IV

biliary excretion

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8
Q

Nafcillin and Dicloxacillin are used for ____

A

gram + only
common for skin infections
MSSA

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9
Q

Amoxicillin and Ampicillin are used for

A

gram + and some gram -

but penicillinase sensitive

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10
Q

Amoxacillin kinetics

A

well absorbed, acid stable

can be taken with food (PO TID)

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11
Q

first line for syphilis

A

Penicillin

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12
Q

first line for GAS

A

Penicillin

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13
Q

tx for MSSA

A

Vancomycin, Nafcillin (IV) or Dicloxacillin (PO)

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14
Q

tx for otitis media

A

amoxicillin

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15
Q

IV/IM tx for pseudomonas

A

Pipericillin

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16
Q

tx for bite wounds

A

ampicillin/sulbactam or amoxicillin/clavulanate

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17
Q

tx for Lyme dz (bergdorferi)

A

ampicillin or amoxicillin

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18
Q

tx for H. flu

A

amp/sulbactam or amoxi/clavulanate

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19
Q

tx for MRSA

A

linezolid, tigecycline, daptomycin

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20
Q

glucosyltransferase (peptidoglycan synthetase) is blocked by ____

A

vancomycin

external phase of cell wall synthesis, step 1

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21
Q

peptidoglycan transpeptidase (penicillin binding protein) is blocked by _____

A
Beta lactase
(external phase of cell wall synthesis, step 2)
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22
Q

4 classes of beta lactams

A

penicillins
cephalosporins
carbapenems
monobactams

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23
Q

which penicillins are penicillinase resistant?

A

nafcillin (IV)

dicloxacillin (PO)

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24
Q

Which penicillin is better absorbed orally? Pen G or Pen VK?

A

Pen VK

used PO QID

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25
Q

why would one give probenecid with penicillin?

A

it inhibits renal tubular secretion of the drug, keeping it in the system longer (longer t1/2)

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26
Q

which drugs have a post antibiotic effect?

A

penicillins

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27
Q

Nafcillin (IV) is excreted via _____

A

bile

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28
Q

PBP-2a

A

mutant peptidoglycan transpeptidase (penicillin binding protein)
makes it resistant to all beta lactams
MRSA has it

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29
Q

1st gen cephalosporins are___

A

Cefazolin (IV)

Cephalexin (PO)

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30
Q

Cefazolin and Cephalexin are resistant to_______ and used for _____ bacteria.

A

penicillinases

gram positive

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31
Q

cephalosporins are excreted via

A

kidney (secreted)

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32
Q

________ is often given prior to surgery to prevent wound infections.

A

Cefazolin (IV)

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33
Q

_______ is the drug of choice for gonorrhea, severe Lyme dz, and meningitis.

A

Ceftriaxone (IV)

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34
Q

_______ is useful for treatment of pseudomonas.

A

Ceftazidime (IV)

“makes pseudomonas turn on a dime”

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35
Q

3rd generation cephalosporins are resistant to _______ and have good penetration of ______.

A

ESBL (extended spectrum beta lactams)

CNS

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36
Q

the broadest spectrum beta lactic class is

A

carbapenems

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37
Q

Cilastin is given with Imipenem to inhibit ______ in the kidney, increasing it’s half life.

A

dehydropeptidase I, which rapidly hydrolyzes imipenem for excretion

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38
Q

Adverse effect of high dose imipenem is ______

A

seizures

esp. be careful with renal failure

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39
Q

Cilastin is not needed with _______ (carbapenem).

A

Meropenem

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40
Q

2nd line drug for pseudomonas (after aminoglycosides)

A

Aztreonam

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41
Q

Aztreonam is useful for treatment of __________.

A

gram negative aerobic rods

enterobacteriae

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42
Q

Which beta lactic has the least cross-allergenicity with penicillins or cephalosporins?

A

Monobactams (Aztreonam)

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43
Q

Which beta-lactam drug should be reserved for “last resort” use?

A

Carbapenems

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44
Q

Vancomycin is only useful for gram ______ bacteria.

A

positive

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45
Q

Vancomycin resistant bacteria have converted D-Ala to _________.

A

D-Lactate

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46
Q

Vancomycin should be reserved for treatment of _________ and _________.

A

MRSA

C. diff

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47
Q

True or False: Vancomycin is absorbed in the gut.

A

False.

Give orally to treat Cdiff to concentrate effect in the GI.

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48
Q

Adverse effects of Vancomycin (name 4)

A

Ototoxicity
Flushing (Red man syndrome)
Nephrotoxicity
Thrombophlebitis

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49
Q

List drugs that are nephrotoxic.

A

Vancomycin

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50
Q

What can se use for vancomycin resistant enterococci (VRE) or MRSA?

A

Linezolid

Daptomycin

51
Q

2nd or 3rd line drug for resistant gram positives or when vancomycin use is contraindicated?

A

Linezolid

52
Q

If your patient is taking Linezolid, they must not be eating foods high in ________ because the drug inhibits ___________.

A

Tyramine

monoamine oxidase

53
Q

Linezolid MOA

A

blocks initiation of protein synthesis

binds to 23S RNA to prevent formation of 70S functional initiation complex

54
Q

Which drug’s MOA is so unique that there is no cross-drug resistance?

A

Linezolid

resistant bacteria have mutated 23S RNA

55
Q

Linezolid is metabolized in the ________

A

liver

no problem for patients with renal failure

56
Q

Myelosuppression is an adverse effect of __________.

A

Linezolid

Drugs that inhibit protein synthesis

57
Q

Rarely, Linezolid can cause _______ (adverse effect).

A

optic neuropathy

peripheral neuropathy

58
Q

3rd/4th line for drug resistant gram +

A

Daptomycin

or when vancomycin & linezolid are contraindicated

59
Q

This drug is a lipopeptide that uniquely forms pores in cell membranes to allow passive K+ efflux (—>depolarization–>death).

A

Daptomycin

60
Q

Daptomycin is not very selective, its lipid tail can also embed in ________, causing _________.

A

muscle

weakness, discomfort, rhabdomyolysis

61
Q

Daptomycin is excreted via ________.

A

urine (kidney)

62
Q

Macrolides bind to _________ to block translocation (stall protein synthesis).

A

50S RNA

63
Q

The ___________ are good for the funny bugs and gram positive organisms.

A

macrolides

64
Q

Bacteria develop cross drug resistance to macrolides, _______, and _________, by __________.

A

lincosamides, streptogramins (MLS)

methylation of the 50S ribosome (“MLS site”)

65
Q

_________ synergistically decrease bioavailability of several drugs, and is inhibited by ________.

A

P-gp/CYP34A
erythromycin & clarithromycin
(not inhibited by azithromycin)

66
Q

Erythromycin & clarithromycin can cause toxicity to ______ and _______.

A

liver

reversible hearing loss

67
Q

____________ and _________ can cause QT prolongation

A

Erythromycin

Fluoroquinolones

68
Q

Ototoxic drugs include:

A

erythromycin

clarithromycin

69
Q

Clarithromycin is “better tolerated” than erythromycin, in reference to _______ side effects.

A

GI

70
Q

Clindamycin is good for treating _______

A

mixed anaerobes (oral > bowel)
gram positive aerobes
MRSA

71
Q

Anti-anaerobes are ________ and ________.

A
L incosamide (clindamycin)
nitroimadazole (metronidazole)
72
Q

treatment for Cdiff

A

oral metronidazole

oral vancomycin

73
Q

Clindamycin is metabolized by ________ so should be dosage adjusted in _______ failure

A

liver

74
Q

Metronidazole is only useful for _________ infections.

A

anaerobic

75
Q

What “gut sterilizer” is often given prior to bowel surgery?

A

metronidazole

76
Q

dark brown urine
metallic taste
disulfiram-like reaction
inhibits p450 enyzmes

A

metronidazole

77
Q

Paraquat (herbicide) causes _______ toxicity.

A

lung

78
Q

The antidote for parathione (pesticides) is ________.

A

atropine sulfate

compete w/ Ach for muscarinic receptor

79
Q

Nitrates exposure results in production of _________.

A

Methemoglobin (Hb(F+++))

80
Q

The antidote for methemoglobinemia is __________

A

methylene blue

reduces Fe+++ to Fe++

81
Q

Cyanide inhibits ___________ which is required in the electron transport chain

A
cytochrome oxidase
(results in switch to anaerobic metabolism)
82
Q

The three antidotes for cyanide is __________.

A

Nitrates. (cyanide binds Fe+++ in methemoglobin)
Hydroxycobalamin (forms complex)
Sodium thiosulfate (forms complex)

83
Q

The antidote for metal poisoning (lead, mercury) is ___________.

A

succimer/DMSA

84
Q

Buy AT 30, Cell at 50.

A

Aminoglycosides
Tetracyclines
inhibit 30S ribosomal subunit

Chloremphenical and Clindamycin
Erythromycin
Lincomycin
Linezolid
inhibit 50S ribosomal subunit
85
Q

Doxycycline is a _________.

A

Tetracycline

86
Q

Tetracyclines MOA

A

anti-protein synthesis
bacteriostatic
reversibly bind 30S subunit
selective to prokaryotes

87
Q

Cross-resistance usually does not extend to _________, which should be reserved for MDR organisms and is only given ______.

A

Tigecycline

IV

88
Q

Doxycycline is primarily _______ soluble with a ______ half life.

A

lipid
long
given PO BID

89
Q

What are the “funny bugs” that Doxycycline can treat?

A

Chlamydia
Rickettsii (Rocky Mt Spotted Fever)
Bergdorferi
Mycoplasma

90
Q

You should not take _________ with a tetracycline. Absorption is impaired by taking with food.

A

antacids

milk

91
Q

Tetracyclines is widely distributed and can accumulate in _______ (what tissue?).

A

bone, teeth

can cause discoloration

92
Q

Tetracyclines are contraindicated in _________, ___________, and __________.

A

renal failure
pregnancy
children < 8

93
Q

If a patient takes expired tetracycline, she/he can develop__________.

A

renal tubular acidosis

94
Q

“Mean” GNATS can NOT kill anaerobes. What is GNATS (hint: bacteria)?

A
Gentamycin
Neomycin
Amikacin
Tobramycin
Streptomycin
95
Q

“Mean” GNATS can NOT kill anaerobes. What is NOT (hint: toxicities)?

A

Nephrotoxic
Ototoxic
Teratogenic

96
Q

inhibits protein synthesis
impairs proof reading
irreversible binding to 30 S subunit – bacteriocidal, with postantibiotic effect
concentration-dependent killing

A

Aminoglycosides

97
Q

Aminoglycosides are highly _________ soluble, making them good for treatment of _______.

A

water

sepsis

98
Q

Why can’t aminoglycosides kill anaerobes?

A

needs an oxygen-dependent pump to cross inner cell membrane (pump is inhibited by low pH)

99
Q

Bacteria develop resistance to aminoglycosides is by _________.

A

enzymatic modification of the drug so that it cannot bind to the ribosome

100
Q

Effective against aerobic gram negative enteric bacteria (including pseudomonas), but not effective against anaerobes.

A

Aminoglycosides

101
Q

Aminoglycosides are typically given with a __________ to compensate for it’s inability to cross cell walls.

A

cell-wall inhibitor
mixed gram + and -: penicillin or vancomycin;
Just gram+: ceftazidime for pseudomonas

102
Q

Aminoglycosides are not given _______ (route of administration).

A

orally

Tobramycin can be nebulized.

103
Q

Why do we not like Chloramphenicol?

A

inhibits CYPs
Gray baby syndrome
bone marrow suppression (aplastic anemia)

104
Q

DNA synthesis inhibitors include which classes of drugs?

A

Antifolates/Sulfonamides
Fluoroquinolone
Nitroimidazole. (metronidazole)

105
Q

Which drug blocks production of dihydrofolate in bacteria?

A

SMX (sulfamethoxazole)

106
Q

Which drug blocks reduction of dihydrofolate to tetrahydrofolate?

A

TMP (trimethoprim)

107
Q

Bacteria can become resistant to sulfonamides by increasing synthesis of _______.

A

PABA (folate precursor)

108
Q

Cotrimoxazole (TMP/SMX) is used for:

A

uncomplicated UTI/prostatits

otitis and sinusitis

109
Q

If you prescribe a sulfonamide, you must instruct the patient to __________.

A

Drink plenty of water.

Drug can crystallize in urine

110
Q

Sulfonamides are contraindicated in _________ because they can cause _______.

A

newborns

kernicteris

111
Q

Which drug class inhibits topoisomerase II (in gram negatives) and IV (in gram positives) to prevent DNA synthesis?

A

Fluoroquinolones

112
Q

Fluoroquinolone are indicated for treatment of:

A
complicated UTI
traveler's diarrhea
drug resistant gram negative rods
anthrax
lung infections (levo &amp; moxi)
113
Q

The respiratory fluoroquinolones are:

A

levofloxacin and moxifloxacin

114
Q

Fluoroquinolone absorption is impaired by:

A

divalent cations (milk, antacids)

115
Q

Fluoroquinolone toxicity/adverse effects

A
growing cartilage 
tendon rupture
acute psychosis (esp with NSAIDS)
drug interactions - inhibits p450
116
Q

Fluoroquinolone are contraindicated in

A

pregnancy

children <18

117
Q

urinary tract antiseptic

A

nitrofurantoin

118
Q

Uncomplicated pyelonephritis can be treated with:

A

ciprofloxacin
levofloxacin
TMP/SMX

119
Q

Nitrofurantoin MOA

A

free radical damage (nonspecific, so rare resistance)

120
Q

Nitrofurantoin contraindications

A

pregnancy
newborns
renal impairment

121
Q

Nitrofurantoin side effect

A

turns urine brown

122
Q

accumulates in the bladder

A

methanamine

123
Q

Uncomplicated bladder infection can be treated with:

A

TMP/SMX
Nitrofurantoin
Methanamine