Exam 1: Antibiotics Flashcards
1
Q
1st Generation Penicillins
A
Penicillin G (IV), Penicillin VK (PO)
2
Q
structural analog of D-Ala D-Ala is ____
A
B-lactam drugs
3
Q
Penicillin pharmacokinetics
A
inactivated by gastric acid
small Vd, short half life
wide distribution but poor CNS penetration
renal secretion
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)
5
Q
Penicillin adverse effects
A
low direct toxicity
kills GI bugs –>Cdiff
CNS tremors or convulsion
hypersensitivity
6
Q
2nd Generation Beta Lactams
A
Nafcillin (IV), Dicloxacillin (PO QID), Methicillin.
Penicillinase resistant
7
Q
Nafcillin pharmacokinetics
A
erratic oral absorption so give IV
biliary excretion
8
Q
Nafcillin and Dicloxacillin are used for ____
A
gram + only
common for skin infections
MSSA
9
Q
Amoxicillin and Ampicillin are used for
A
gram + and some gram -
but penicillinase sensitive
10
Q
Amoxacillin kinetics
A
well absorbed, acid stable
can be taken with food (PO TID)
11
Q
first line for syphilis
A
Penicillin
12
Q
first line for GAS
A
Penicillin
13
Q
tx for MSSA
A
Vancomycin, Nafcillin (IV) or Dicloxacillin (PO)
14
Q
tx for otitis media
A
amoxicillin
15
Q
IV/IM tx for pseudomonas
A
Pipericillin
16
Q
tx for bite wounds
A
ampicillin/sulbactam or amoxicillin/clavulanate
17
Q
tx for Lyme dz (bergdorferi)
A
ampicillin or amoxicillin
18
Q
tx for H. flu
A
amp/sulbactam or amoxi/clavulanate
19
Q
tx for MRSA
A
linezolid, tigecycline, daptomycin
20
Q
glucosyltransferase (peptidoglycan synthetase) is blocked by ____
A
vancomycin
external phase of cell wall synthesis, step 1
21
Q
peptidoglycan transpeptidase (penicillin binding protein) is blocked by _____
A
Beta lactase (external phase of cell wall synthesis, step 2)
22
Q
4 classes of beta lactams
A
penicillins
cephalosporins
carbapenems
monobactams
23
Q
which penicillins are penicillinase resistant?
A
nafcillin (IV)
dicloxacillin (PO)
24
Q
Which penicillin is better absorbed orally? Pen G or Pen VK?
A
Pen VK
used PO QID
25
why would one give probenecid with penicillin?
it inhibits renal tubular secretion of the drug, keeping it in the system longer (longer t1/2)
26
which drugs have a post antibiotic effect?
penicillins
27
Nafcillin (IV) is excreted via _____
bile
28
PBP-2a
mutant peptidoglycan transpeptidase (penicillin binding protein)
makes it resistant to all beta lactams
MRSA has it
29
1st gen cephalosporins are___
Cefazolin (IV)
| Cephalexin (PO)
30
Cefazolin and Cephalexin are resistant to_______ and used for _____ bacteria.
penicillinases
| gram positive
31
cephalosporins are excreted via
kidney (secreted)
32
________ is often given prior to surgery to prevent wound infections.
Cefazolin (IV)
33
_______ is the drug of choice for gonorrhea, severe Lyme dz, and meningitis.
Ceftriaxone (IV)
34
_______ is useful for treatment of pseudomonas.
Ceftazidime (IV)
"makes pseudomonas turn on a dime"
35
3rd generation cephalosporins are resistant to _______ and have good penetration of ______.
ESBL (extended spectrum beta lactams)
| CNS
36
the broadest spectrum beta lactic class is
carbapenems
37
Cilastin is given with Imipenem to inhibit ______ in the kidney, increasing it's half life.
dehydropeptidase I, which rapidly hydrolyzes imipenem for excretion
38
Adverse effect of high dose imipenem is ______
seizures
| esp. be careful with renal failure
39
Cilastin is not needed with _______ (carbapenem).
Meropenem
40
2nd line drug for pseudomonas (after aminoglycosides)
Aztreonam
41
Aztreonam is useful for treatment of __________.
gram negative aerobic rods
| enterobacteriae
42
Which beta lactic has the least cross-allergenicity with penicillins or cephalosporins?
Monobactams (Aztreonam)
43
Which beta-lactam drug should be reserved for "last resort" use?
Carbapenems
44
Vancomycin is only useful for gram ______ bacteria.
positive
45
Vancomycin resistant bacteria have converted D-Ala to _________.
D-Lactate
46
Vancomycin should be reserved for treatment of _________ and _________.
MRSA
| C. diff
47
True or False: Vancomycin is absorbed in the gut.
False.
Give orally to treat Cdiff to concentrate effect in the GI.
48
Adverse effects of Vancomycin (name 4)
Ototoxicity
Flushing (Red man syndrome)
Nephrotoxicity
Thrombophlebitis
49
List drugs that are nephrotoxic.
Vancomycin
50
What can se use for vancomycin resistant enterococci (VRE) or MRSA?
Linezolid
| Daptomycin
51
2nd or 3rd line drug for resistant gram positives or when vancomycin use is contraindicated?
Linezolid
52
If your patient is taking Linezolid, they must not be eating foods high in ________ because the drug inhibits ___________.
Tyramine
| monoamine oxidase
53
Linezolid MOA
blocks initiation of protein synthesis
| binds to 23S RNA to prevent formation of 70S functional initiation complex
54
Which drug's MOA is so unique that there is no cross-drug resistance?
Linezolid
| resistant bacteria have mutated 23S RNA
55
Linezolid is metabolized in the ________
liver
| no problem for patients with renal failure
56
Myelosuppression is an adverse effect of __________.
Linezolid
| Drugs that inhibit protein synthesis
57
Rarely, Linezolid can cause _______ (adverse effect).
optic neuropathy
| peripheral neuropathy
58
3rd/4th line for drug resistant gram +
Daptomycin
| or when vancomycin & linezolid are contraindicated
59
This drug is a lipopeptide that uniquely forms pores in cell membranes to allow passive K+ efflux (--->depolarization-->death).
Daptomycin
60
Daptomycin is not very selective, its lipid tail can also embed in ________, causing _________.
muscle
| weakness, discomfort, rhabdomyolysis
61
Daptomycin is excreted via ________.
urine (kidney)
62
Macrolides bind to _________ to block translocation (stall protein synthesis).
50S RNA
63
The ___________ are good for the funny bugs and gram positive organisms.
macrolides
64
Bacteria develop cross drug resistance to macrolides, _______, and _________, by __________.
lincosamides, streptogramins (MLS)
| methylation of the 50S ribosome ("MLS site")
65
_________ synergistically decrease bioavailability of several drugs, and is inhibited by ________.
P-gp/CYP34A
erythromycin & clarithromycin
(not inhibited by azithromycin)
66
Erythromycin & clarithromycin can cause toxicity to ______ and _______.
liver
| reversible hearing loss
67
____________ and _________ can cause QT prolongation
Erythromycin
| Fluoroquinolones
68
Ototoxic drugs include:
erythromycin
| clarithromycin
69
Clarithromycin is "better tolerated" than erythromycin, in reference to _______ side effects.
GI
70
Clindamycin is good for treating _______
mixed anaerobes (oral > bowel)
gram positive aerobes
MRSA
71
Anti-anaerobes are ________ and ________.
```
L incosamide (clindamycin)
nitroimadazole (metronidazole)
```
72
treatment for Cdiff
oral metronidazole
| oral vancomycin
73
Clindamycin is metabolized by ________ so should be dosage adjusted in _______ failure
liver
74
Metronidazole is only useful for _________ infections.
anaerobic
75
What "gut sterilizer" is often given prior to bowel surgery?
metronidazole
76
dark brown urine
metallic taste
disulfiram-like reaction
inhibits p450 enyzmes
metronidazole
77
Paraquat (herbicide) causes _______ toxicity.
lung
78
The antidote for parathione (pesticides) is ________.
atropine sulfate
| compete w/ Ach for muscarinic receptor
79
Nitrates exposure results in production of _________.
Methemoglobin (Hb(F+++))
80
The antidote for methemoglobinemia is __________
methylene blue
| reduces Fe+++ to Fe++
81
Cyanide inhibits ___________ which is required in the electron transport chain
```
cytochrome oxidase
(results in switch to anaerobic metabolism)
```
82
The three antidotes for cyanide is __________.
Nitrates. (cyanide binds Fe+++ in methemoglobin)
Hydroxycobalamin (forms complex)
Sodium thiosulfate (forms complex)
83
The antidote for metal poisoning (lead, mercury) is ___________.
succimer/DMSA
84
Buy AT 30, Cell at 50.
Aminoglycosides
Tetracyclines
inhibit 30S ribosomal subunit
```
Chloremphenical and Clindamycin
Erythromycin
Lincomycin
Linezolid
inhibit 50S ribosomal subunit
```
85
Doxycycline is a _________.
Tetracycline
86
Tetracyclines MOA
anti-protein synthesis
bacteriostatic
reversibly bind 30S subunit
selective to prokaryotes
87
Cross-resistance usually does not extend to _________, which should be reserved for MDR organisms and is only given ______.
Tigecycline
| IV
88
Doxycycline is primarily _______ soluble with a ______ half life.
lipid
long
given PO BID
89
What are the "funny bugs" that Doxycycline can treat?
Chlamydia
Rickettsii (Rocky Mt Spotted Fever)
Bergdorferi
Mycoplasma
90
You should not take _________ with a tetracycline. Absorption is impaired by taking with food.
antacids
| milk
91
Tetracyclines is widely distributed and can accumulate in _______ (what tissue?).
bone, teeth
| can cause discoloration
92
Tetracyclines are contraindicated in _________, ___________, and __________.
renal failure
pregnancy
children < 8
93
If a patient takes expired tetracycline, she/he can develop__________.
renal tubular acidosis
94
"Mean" GNATS can NOT kill anaerobes. What is GNATS (hint: bacteria)?
```
Gentamycin
Neomycin
Amikacin
Tobramycin
Streptomycin
```
95
"Mean" GNATS can NOT kill anaerobes. What is NOT (hint: toxicities)?
Nephrotoxic
Ototoxic
Teratogenic
96
inhibits protein synthesis
impairs proof reading
irreversible binding to 30 S subunit -- bacteriocidal, with postantibiotic effect
concentration-dependent killing
Aminoglycosides
97
Aminoglycosides are highly _________ soluble, making them good for treatment of _______.
water
| sepsis
98
Why can't aminoglycosides kill anaerobes?
needs an oxygen-dependent pump to cross inner cell membrane (pump is inhibited by low pH)
99
Bacteria develop resistance to aminoglycosides is by _________.
enzymatic modification of the drug so that it cannot bind to the ribosome
100
Effective against aerobic gram negative enteric bacteria (including pseudomonas), but not effective against anaerobes.
Aminoglycosides
101
Aminoglycosides are typically given with a __________ to compensate for it's inability to cross cell walls.
cell-wall inhibitor
mixed gram + and -: penicillin or vancomycin;
Just gram+: ceftazidime for pseudomonas
102
Aminoglycosides are not given _______ (route of administration).
orally
| Tobramycin can be nebulized.
103
Why do we not like Chloramphenicol?
inhibits CYPs
Gray baby syndrome
bone marrow suppression (aplastic anemia)
104
DNA synthesis inhibitors include which classes of drugs?
Antifolates/Sulfonamides
Fluoroquinolone
Nitroimidazole. (metronidazole)
105
Which drug blocks production of dihydrofolate in bacteria?
SMX (sulfamethoxazole)
106
Which drug blocks reduction of dihydrofolate to tetrahydrofolate?
TMP (trimethoprim)
107
Bacteria can become resistant to sulfonamides by increasing synthesis of _______.
PABA (folate precursor)
108
Cotrimoxazole (TMP/SMX) is used for:
uncomplicated UTI/prostatits
| otitis and sinusitis
109
If you prescribe a sulfonamide, you must instruct the patient to __________.
Drink plenty of water.
| Drug can crystallize in urine
110
Sulfonamides are contraindicated in _________ because they can cause _______.
newborns
| kernicteris
111
Which drug class inhibits topoisomerase II (in gram negatives) and IV (in gram positives) to prevent DNA synthesis?
Fluoroquinolones
112
Fluoroquinolone are indicated for treatment of:
```
complicated UTI
traveler's diarrhea
drug resistant gram negative rods
anthrax
lung infections (levo & moxi)
```
113
The respiratory fluoroquinolones are:
levofloxacin and moxifloxacin
114
Fluoroquinolone absorption is impaired by:
divalent cations (milk, antacids)
115
Fluoroquinolone toxicity/adverse effects
```
growing cartilage
tendon rupture
acute psychosis (esp with NSAIDS)
drug interactions - inhibits p450
```
116
Fluoroquinolone are contraindicated in
pregnancy
| children <18
117
urinary tract antiseptic
nitrofurantoin
118
Uncomplicated pyelonephritis can be treated with:
ciprofloxacin
levofloxacin
TMP/SMX
119
Nitrofurantoin MOA
free radical damage (nonspecific, so rare resistance)
120
Nitrofurantoin contraindications
pregnancy
newborns
renal impairment
121
Nitrofurantoin side effect
turns urine brown
122
accumulates in the bladder
methanamine
123
Uncomplicated bladder infection can be treated with:
TMP/SMX
Nitrofurantoin
Methanamine
