antibiotics pharmacology 1 Flashcards
(181 cards)
1
Q
what is the smallest organism?
A
bacteria.
2
Q
a substance which destroys or inhibits the growth of microorganisms?
A
antimicrobial.
3
Q
a substance that destroys or inhibit the growth or action of microorganisms on living tissue.
A
antiseptic.
4
Q
a substance produced by or derived from microorganism and able to inhibit or kill another microorganism.
A
antibiotic.
5
Q
lowest concentration that results in inhibition of visible growth?
A
minimum inhibitory concentration (MIC).
6
Q
lowest concentration that kills 99.9% of the original inoculum.
A
minimum bactericidal concentration (MBC).
7
Q
MBC and MIC, are which type of testing?
A
antibiotic susceptibility testing (in vitro).
8
Q
Antibiotics are classified based on what?
A
1- mechanism of action.
2- chemical structure.
3- spectrum of activity.
9
Q
List the mechanisms of action of bacteriostatic?
A
1- inhibition of DNA gyrase and RNA polymerase.
2- inhibition of protein synthesis.
3- inhibition of folic acid metabolism.
10
Q
Give an example of bacteriostatic antibiotics that inhibit DNA gyrase and RNA polymerase?
A
Quinolones and Rifampin.
11
Q
Give an example of bacteriostatic antibiotics that inhibit protein synthesis?
A
Tetracyclines, erythromycin, aminoglycosides and chloramphenicol.
12
Q
Give an example of bacteriostatic antibiotics that inhibit folic acid metabolism?
A
Trimethoprim and sulfonamides.
13
Q
What is the mechanism of action of bactericidal antibiotics?
A
Inhibition of cell wall synthesis.
14
Q
Give an example of bactericidal antibiotics that inhibit cell wall synthesis?
A
Penicillins, cephalosporins, monobactams and vancomycin.
15
Q
List classes of antibiotics?
A
1- beta- lactams.
2- macrolides.
3- quinolones.
4- aminoglycosides.
5- glycopeptides.
6- tetracyclines.
7- glycecyclines.
8- trimethoprim - sulfamethoxazole.
9- rifampin and rifabutine.
10- chloramphenicol.
11- metronidazole.
12- linconycoines.
13- streptogramins.
14- lipopeptides.
16
Q
Give examples of beta-lactams?
A
1- penicillins.
2- cephalosporins.
3- monobactams.
4- carbapenems.
17
Q
Give examples of macrolides?
A
1- erythromycin.
2- clarithromycin.
3- azithromycin.
18
Q
Give examples of quinolones?
A
1- ciprofloxacin.
2- ofloxacin.
3- norfloxacin.
4- sparfloxacin d/ced.
5- levofloxacin.
6- trovafloxacin d/ced.
7- gatifloxacin d/ced.
8- moxifloxacin.
19
Q
Give examples of aminoglycosides?
A
1- streptomycin.
2- gentamicin.
3- tobramicin.
4- amikacin.
20
Q
Give an example of glycopeptides?
A
Vancomycin and teicoplanin.
21
Q
Give examples of tetracyclines?
A
1- tetracycline.
2- doxycycline.
3- minocycline.
22
Q
Give an example of glycecyclines?
A
Tigecycline.
23
Q
Give an example of lincomycoines?
A
Clindamycin.
24
Q
Give an example of streptogramins?
A
Quinupristin and dalfopristin.
25
Give an example of lipopeptides?
Daptomycin.
26
what is the MOA of beta-lactams?
inhibits cell wall synthesis (bactericidal).
27
beta lactams are bactericidal except against?
enterococcus sp.
28
beta lactams are _______ killers?
time-dependant killers.
29
beta lactams have ____ elimination half-time?
short.
30
how are beta lactams eliminated?
renally.
31
which beta lactams are not eliminated renally?
nafcillin.
oxacillin.
ceftriaxone.
cefoperazone.
32
beta lactams show cross _______?
cross- allergenicity.
33
which beta lactams doesn't show cross allergenicity?
aztreonam.
34
what is the absorption of beta lactams?
variable depending on product.
35
what is the distribution method of beta lactams?
widely distributed into tissues and fluids.
36
which beta lactams only get into CSF in the presence of inflamed meninges?
pens
37
which Abx can penetrate the CSF?
parenteral 3rd and 4th generation cephs, meropenem and aztreonam.
38
what is the elimination method of beta lactams?
eliminated primarily by the kidney.
39
dosage adj of beta lactams required in the presence of ?
renal insufficiency.
40
which beta lactams are eliminated by the liver?
nafcillin,
oxacillin,
ceftriaxone.
41
all beta lactams have short elimination half-lives except?
a few cephalosporins (ceftriaxone).
42
list the neurological adverse effects of beta lactams?
irritability, confusion, seizures.
43
list the hematological adverse effects of beta lactams?
leukopenia, neutropenia, thrombocytopenia - prolonged therapy (>2).
44
list the gastrointestinal adverse effects of beta lactams?
increased LFTs , nausea, vomiting, diarrhea, pseudomembranous colitis (C.difficile diarrhea).
45
list the renal adverse effects of beta lactams and with which drugs?
cellular infiltration in renal tubules. especially with methicillin or nafcillin.
46
what is the most important and most common mechanism of resistance of beta lactams?
production of beta lactamase enzyme.
47
which beta lactam inhibits cross linking?
penicillin.
48
list the types of penicillins?
1- natural penicillins.
2- penicillinase - resistant penicillins.
3- aminopenicillins.
4- carboxypenicillins.
5- ureidopenicillins.
49
give examples of natural penicillins?
penicillin G, and penicillin VK.
50
give examples of penicillinase - resistant penicillins?
nafcillin, oxacillin, methicillin, cloxacillin.
51
give examples of aminopenicillins?
ampicillin, amoxicillin.
52
give examples of carboxypenicillins?
carbenicillin, ticarcillin.
53
give examples of ureidopenicillins?
piperacillin, azlocillin.
54
natural penicillins work the best agansit?
gram positive bacteria.
55
why were penicillinase-resistant penicillins developed?
overcome the penicillinase enzyme of S.aureus which inactivates natural penicillins.
56
penicillinase resistant penicillins work best against?
gram positive penicillinase s.aureus
57
why were aminopenicillins developed?
to increase activity against gram negative aerobes,
58
why were carboxypenicillins developed?
to further increase activity against resistant gram - negative aerobes.
59
carboxypenicillins work best against?
gram negative bacteria.
60
list beta lactamase inhibitor combos?
unasyn, augmentin, timentin, zosyn, tazocin.
61
why were beta lactamase inhibitor combos developed?
to gain or enhance activity against beta lactamase producing organisms.
62
cephalosporins are divided into generations based on what?
1- antimicrobial activity.
2- resistance to beta - lactamase.
63
list first gen cephalosporins?
cefazolin and cephalexin.
64
first generation cephalosporins have best activity against?
gram positive aerobes with limited activity against a few gram negative aerobes.
65
list the gram negative aerobes which first gen cephalosporins work against?
1- e.coli.
2- k.pneumoniae.
3- p.mirabilis.
66
list second generation cephalosporins?
cefuroxime.
cefuroxime-axetil.
cefoxitin.
cefotetan.
cefmetazole.
67
list activity spectrum of second gen cephalosporins?
slightly less active against gram positive aerobes, but more active against gram negative aerobes, little activity against anaerobes.
68
list the 2nd gen cephalosporins which have activity against anaerobes?
cefoxitin, cefotetan and cefmetazole.
69
list the spectrum of activity of cefoxitin, cefotetan and cefmetazole?
bacteroides fragilis and it's group.
70
list third generation cephalosporins?
ceftriaxone, ceftazidime, cefotaxime, cefixime, cefdinir.
71
list the spectrum of activity of 3rd gen cephalosporins?
less active against gram positive aerobes but have greater activity against gram negative aerobes.
72
which cephalosporins have the best activity against gram positive aerobes including pen-resistant S.pneumoniae?
ceftriaxone and cefotaxime.
73
list 4th gen cephalosporins?
cefipime and cefpirome.
74
which 4ht gen cephalosporins are currently available?
cefipime and cefpirome.
75
list spectrum of activity of 4th gen cephalosporins?
mostly G-
76
list 5th gen cephalosporins?
ceftaroline and ceftobiprole.
77
what is the spectrum of activity of 5th gen cephalosporins?
only MRSA.
78
list carbapenems?
imipenem and meropenem.
79
which antibiotics have the most broad spectrum of activity of all antimicrobials?
carbapenems.
80
list spectrum of activity of carbapenems?
gram+ and gram- aerobes and anaerobes.
81
bacteria not covered by carbapenems include?
MRSA, VRE, coagulase-negative staph, C.difficile, S.maltophilia, nocardia.
82
imipenem is combined with what to prevent hydrolysis by enzymes in the renal brush border?
cilastatin.
83
give an example of monobactams?
aztreonam.
84
what is the spectrum of activity of aztreonam?
bind preferentially to PBP 3 of gram - aerobes; has little to no activity against gram + ot anaerobes.
85
which antibiotics are a novel group of synthetic antibiotics developed in response to growing resistance?
fluoroquinolones.
86
fluoroquinolones available today are all structural derivatives of what?
nalidixic acid.
87
list the therapeutic advances of fluorinated quinolones?
- broad spectrum of activity.
- improved PK properties, excellent bioavailability, tissue penetration, prolonged half-lives.
- overall safety.
88
list older FQs?
- norfloxacin.
- ciprofloxacin.
89
list newer FQs?
- levofloxacin.
- gatifloxacin.
- moxifloxacin.
90
list FQs spectrum of activity against G+?
- older agents have poor activity against G+.
- newer agents have enhanced potency against G+.
91
which FQs have best activity against pseudomonas aeruginosa?
ciprofloxacin and levoflaxcin.
92
list FQs spectrum of activity against G-?
all FQs have excellent activity against G-.
(cipro=levo> gato> moxi).
93
list FQs spectrum of activity against anaerobes?
only trovafloxacin has adequate activity against bacteroides sp.
94
list FQs spectrum of activity against atypical bacteria?
all FQs have excellent activity against atypical bacteria.
95
list FQs spectrum of activity against other bacteria?
TB and bacillus anthracis (2nd line drugs for TB).
96
what is the mechanism of killing of FQs?
concentration dependant bacterial killing.
97
what is the mechanism of absorption of FQs?
Cmax within 1-2 hours; co administration with food delays peak concentration.
98
what is the mechanism of distribution of FQs?
extensive tissue distribution - prostate; liver; lung; skin/soft tissue and bone; urinary tract.
minimal CSF penetration.
99
what is the mechanism of elimination of FQs?
Renal and hepatic; not removed by HD.
100
list the gastrointestinal adverse effects of FQs?
nausea, vomiting, diarrhea, dyspepsia.
101
list the CNS adverse effects of FQs?
headache, agitation, insomnia, dizziness, rarely hallucinations and seizures (elderly).
102
list the hepatic adverse effects of FQs?
LFT elevation led to withdrawal of trovafloxacin.
103
phototoxicity with FQ is more common with______?
older FQs, uncommon with current FQs.
104
list the cardiac adverse effects of FQs?
variable prolongation in QTc interval, led to withdrawal of grepafloxacin and saprfloxacin.
105
which FQs are banned?
grepafloxacin and saprfloxacin.
106
FQs are contraindicated in which groups and why?
pediatrics, and pregnant or breast feeding women because of articular cartilage damage.
107
list the other adverse effects of FQs?
tendon rupture, dysglycemia, hypersensitivity.
108
list macrolides?
1- erythromycin.
2- clarithromycin.
3- azithromycin.
109
which macrolide is naturally occurring derived from streptomyces erythreus?
erythromycin.
110
which macrolide has problems with acid lability, narrow spectrum, poor GI intolerance, and short elimination half life?
erythromycin,
111
which macrolides have broader spectrum of activity, improved PK properties (better bioavailability, better tissue penetration, prolonged half- lives, improved tolerability?
clarithromycin and azithromycin.
112
list the spectrum, of activity of macrolides against gram + aerobes?
erythromycin and clarithromycin display best activity,
(clarithro> erythro> azithro).
113
resistance against macrolides is developing with which G+ bacteria?
streptococcus pneumoniae.
114
list the spectrum, of activity of macrolides against gram - aerobes?
newer macrolides with enhanced activity (azithro> clarithro> erythro)>
does not have activity against any enterobacteriaceae.
H.influenzae (nor erythro), M. catarrhalis, Neisseria sp.
115
list the spectrum, of activity of macrolides against anaeobes?
activity against upper airway anaerobes.
116
list the spectrum, of activity of macrolides against atypical bacteria?
all have excellent activity against atypical bacteria.
117
macrolides are the DOC against which atypical bacteria?
legionella pneumophila.
118
list the mechanism of absorption of erythromycin?
variable absorption (15-45%); food may decrease absorption.
base: destroyed by gastric acid; enteric coated.
esters and ester salts: more acid stable.
119
list the mechanism of absorption of clarithromycin?
acid stable and well absorbed, 55% bioavailable regardless of presence of food.
120
list the mechanism of absorption of azithromycin?
acid stable; 38% bioavailable; food decreases absorption of capsules.
121
list the mechanism of distribution of macrolides?
extensive tissue and cellular distribution - clarithromycin and azithromycin with extensive penetration.
minimal CSF penetration.
122
Which macrolide is the only macrolide eliminated by the kidney?
Clarithromycin
123
Which macrolides are hepatically eliminated?
All
124
List the gastrointestinal adverse effects of macrolides?
Nausea, vomiting, diarrhea, dyspepsia.
125
Gastrointestinal adverse effects of macrolides are more common with which macrolide?
Erythromycin.
126
Thrombophlebitis is a risk with which macrolides?
IV erythro and azithro.
127
Which macrolides are inhibitors of cytochrome p450 in the liver?
Erythromycin and clarithromycin.
128
Erythromycin and clarithromycin may increase the concentration of which drugs?
Theophylline, carbamazepine, cyclosporine, phenytoin, warfarin, digoxin, disopyramide, valporic acid, terfenadine, astemizole, cisapride, ergot alkaloids.
129
What is the MOA of aminoglycosides?
Inhibition of protein synthesis, irreversibly bind to 30s ribosomes and are bactericidal.
130
List aminoglycosides?
1-gentamicin.
2- amikacin.
3- tobramycin.
4- streptomycin.
131
Aminoglycosides work best against what?
Gram negative aerobes.
132
List side effects of aminoglycoside?
1- nephrotoxicity: reversible if caught early.
2- ototoxicity: tinnitus, decreased hearing.
133
What is the first antibiotic that works against TB?
Streptomycin.
134
Which drug combination produces a sequential
blocking of the folic acid synthesis pathway,
producing a synergistic action?
Trimethoprim - sulfamethoxazole.
135
What is the spectrum of activity of trimethoprim - sulfamethoxazole?
Gram negative > gram positive aerobes.
136
List the clinical uses of trimethoprim - sulfamethoxazole?
1- PCP.
2- UTI.
3- Brucella infection.
137
List the spectrum of activity of vancomycin/ teicoplanin?
Gram positive bacteria (including MRSA and C.difficile).
No activity against gram - negative aerobes or anaerobes.
138
List glycopeptides?
1- vancomycin.
2- teicoplanin.
139
List the MOA of vancomycin?
- inhibits bacterial cell wall synthesis at a site different than beta-lactams.
- bactericidal (except for enterococcus).
140
List the clinical uses of vancomycin / teicoplanin?
1- infections due to MRSA.
2- serious G+ infections in b-lactam allergic patients.
3- infections caused by MDR bacteria.
4- endocarditis or surgical prophylaxis.
5- orally for refractory C.difficile colitis.
6- BOTH need adjustment in renal failure.
141
Which antibiotic causes red-man syndrome?
Vancomycin.
142
Red man syndrome is related to ______ of IV infusion?
Rate
143
You can pretreat red man syndrome with what?
Antihistamines.
144
What is the first available agent which received FDA
approval?
Linezolid.
145
Why was linezolid developed?
In response to need for agents with activity against resistant gram+ (MRSA,GISA,VISA,VRE).
146
What is the main side effect of linezolid?
Thrombocytopenia.
147
What is the spectrum of activity of linezolid?
G+ bacteria.
And atypical bacteria: mycoplasma, chlamydia, legionella.
148
List the MOA of linezolid?
Bacteriostatic.
Inhibits protein synthesis by binding to the 50s ribosomal subunit neat to surface interface of 30S subunit – causes inhibition of 70S initiation complex which inhibits protein synthesis.
149
What is the absorption of linezolid?
100% bioavailable.
150
What is the distribution of linezolid?
Readily distributes into well-perfused tissue.
CSF penetration = 70%.
151
What is the adverse effects of linezolid?
- gastrointestinal: nausea, vomiting, diarrhea (6 to 8%).
- headache (6.5%).
- thrombocytopenia (2-4%)
Most often with treatment duration > 2 weeks
152
Which food inhibits MOA of linezolid?
Linezolid inhibits monoamine oxidase, so patients should avoid consuming large amounts of food or beverages with high tyramine content.
153
List streptogramins?
Quinupristin,
Dalfopristin.
154
Quinupristin and Dalfopristin are most active against which bacteria?
MRSA and E.faecium.
155
How are Quinupristin and Dalfopristin cleared?
Hepatically.
156
List lipopeptides?
Daptomycin.
157
List spectrum of activity of daptomycin?
G+ bacteria including (VRE, MRSA, VISA, VRSA).
158
What is the MOA of daptomycin?
Bactericidal, works on cell MEMBRANE and
disrupt protein synthesis
159
Daptomycin is approved for what?
Skin/ skin structure infections, endocarditis caused by MRSA.
160
List adverse effects of daptomycin?
Causes myositis specially in high doses.
161
Which antibiotic also works against anaerobic protozoa?
Metronidazole.
162
Metronidazole is the drug of choice for which bacteria?
Anaerobic bacteria (c.difficile).
163
List tetracyclines?
1- tetracyclines (IV).
2- doxycyclines (PO/IV).
3- minocycline (PO).
164
What is the MOA of tetracyclines?
Bacteriostatic.
165
What is spectrum of activity of tetracyclines?
G+, G-, some anaerobes.
166
List clinical uses of doxycyclines?
Respiratory tract infections caused by mycoplasma, chlamydia and legionella.
167
List clinical uses of minocyclines?
Commonly used in the treatment of acne.
168
List clinical uses of tetracyclines?
Unusual infections caused by rickettsia (Rocky mountain spotted fever).
169
Tigecyclines covers which type of bacteria?
Resistant bacteria (VRE, MRSA, MDR acinetobacter).
170
Tigecyclines does not cover what?
Pseudomonas and proteus.
171
Tigecyclines are approved only for which type of infection?
Skin and soft tissue infections, and intra-abdominal infections.
172
What is the MOA of Rifampin, rifampicin and rifabutin?
Bactericidal, inhibit initiation of mRNA synthesis.
173
What is the spectrum of activity of rifampin, rifampicin and rifabutin?
Wide spectrum, used the most for the treatment of TB.
174
Which antibiotic is used in combination therapy since resistance is common?
Rifampin
175
List types of antibiotic use?
1- prophylaxis (medical, procedural).
2- empiric.
3- definitive.
176
Syphilis is susceptible to which antibiotic?
Penicillin G.
177
What do you use for MS-SA endocarditis?
Nafcillin and agents.
178
What do use for post-partum endometritis?
Amp/gent/clinda.
179
H.W. is a 38-year-old woman who presents with high fever, malaise, dry cough, nasal congestion, and severe headaches. Her symptoms began suddenly 3 days ago, and she has been in bed ever since. She reports no other illness in her family, but a number of people have called in sick recently at work. Which one of the following should H.W. be given?
A. Azithromycin 500 mg followed by 250 mg/day
orally for 4 more days.
B. Amoxicillin/clavulanic acid 875 mg orally 2
times/day.
C. Oseltamivir 75 mg orally 2 times/day for 5 days.
D. Symptomatic treatment only
D.
180
N.R. is a 28-year-old woman who presents to the clinic with a 2-day history of dysuria, frequency, and urgency. She has no significant medical history, and the only medication she takes is oral contraceptives. Which one of the following would be the best empiric therapy for N.R.?
A. Oral amoxicillin 3 g single dose.
B. Oral ciprofloxacin 500 mg 2 times/day for 7 days. C. Oral trimethoprim/sulfamethoxazole (TMP/SMZ)
DS 2 times/day for 3 days.
D. Oral cephalexin 500 mg 4 times/day for 3 days.
C
181
P.T. is a 52-year-old man who comes to the clinic
with symptoms of a respiratory tract
infection,including a cough that produces sputum.
A sputumculture is obtained that grows
Streptococcus pneumoniae. The minimum
inhibitory concentration (MIC) to penicillin is 0.5
mg/L.
How will this MIC affect P.T.’s therapy?
A. Penicillins and cephalosporins will still be
effective, but higher doses should be used.
B. β-lactam antibiotics will be ineffective; a
macrolide or tetracycline would be a better choice.
C. β-lactam antibiotics will be ineffective; a
fluoroquinolone would be a better choice.
D. Intravenous (IV) therapy with a carbapenem
or vancomycin is required.
A
