Contemporary Antibiotics Flashcards
(179 cards)
1
Q
Community resistance is occurring to emerging resistance to?
A
Prevotella (anaerobe)
2
Q
Are bactericidal or bacteriostatic drugs more preferable?
A
Cidal
3
Q
Are bactericidal or bacteriostatic drugs seen with “post antibiotic effects”?
A
Static
4
Q
What is the Post Antibiotic Effect (PAE)?
A
Defined as persistent suppression of bacterial growth after a brief exposure (1 or 2 hours) of bacteria to an antibiotic even in the absence of host defense mechanisms
5
Q
What may PAE be related to?
A
DNA alteration
6
Q
Is narrow or broad spectrum better?
A
Narrow
7
Q
Why is narrow spectrum better?
A
Often more effective and less alteration of normal flora (thus less super infection)
8
Q
Is Penicillin VK narrow or broad?
A
Narrow
9
Q
Is Amoxicillin narrow or broad?
A
Broad
10
Q
Is Cephalexin narrow or broad?
A
Broad
11
Q
Is dosage more critical with cidal or static drugs?
A
Static
12
Q
Too much of a drug can lead to?
A
Toxicity
13
Q
Too little of a drug can lead to?
A
Resistance
14
Q
What is “loading dose”?
A
Initial higher dose of a drug that may be given at the beginning of a course of treatment before dropping down to a lower maintenance dose; 2-4x therapeutic dose
15
Q
What are two instances where you would give a loading dose?
A
If half life >3h or if need therapeutic dose in <12 h
16
Q
Dosage is determined by?
A
MIC (minimum inhibitory concentration)
17
Q
What is MIC?
A
Minimum concentration of a drug that will prevent visible growth of bacteria in culture after an overnight incubation
18
Q
Is MIC used only as a guide to therapy?
A
Yes; cannot tell us what concentration is at infection
19
Q
Is rebound infection common in oral/facial infection of odontogenic origin?
A
No
20
Q
When to terminate antibiotic?
A
When you are sure patient is on their way to recover based on clinical evaluation
21
Q
What are 3 adverse effects of antibiotics?
A
Toxicity, allergy, and super infection
22
Q
Which class of drugs cause heptaotoxicity?
A
Antifungals
23
Q
Which drugs cause nephrotoxicity?
A
Penicillin, aminoglycosides
24
Q
Which class of drugs cause neurotoxicity?
A
Aminoglycosides
25
Which drug affects blood and blood forming organs?
Chloramphenicol
26
How does Chloramphenicol cause its side effects?
Destruction of normal flora needed for Vitamin K absorption
27
Penicillin shows cross allergy with?
Cephalosporin
28
What percentage of the time do we see Penicillin-Cephalosporin cross allergy?
10-15%
29
Is toxicity or allergy dose-dependent?
Toxicity only
30
Can a single dose/exposure of antibiotic cause someone to have an IgE mediated response (redness, swelling, wheezing)
Yes, because toxicity is dose-dependent
31
In which age groups is superinfection more common?
Young and old
32
Is superinfection more common with narrow or broad spectrum therapy?
Broad
33
What are two examples of superinfection?
Pseudomembranous colitis (C. Dif) and Candida
34
Which three antibiotics are linked to pseudomembranous colitis?
Cephalosporins, ampicillin, clindamycin
35
What is used to treat pseudomembranous colitis?
Metronidazole
36
What used to be used to treat pseudomembranous colitis?
Oral vancomycin
37
Are oral bacteria usually the primary pathogens in orofacial infection?
No; and generally several organisms, not just one
38
From narrow to wide, order the five main beta-lactam antibiotics
Penicillins, cephalosporins, carbapenems, monobactams, carbacephems
39
What are the two types of natural penicillins?
PCN V and G
40
What are the two types of beta-lactamase resistant penicillins?
Oxacillin and dicloxacillin
41
Compared to PCN G, PCN V has?
More reliable oral absorption
42
What is the mechanism of action of penicillins?
Cell wall synthesis disruption (prevents cross linking)
43
Are penicillins cidal or static?
Cidal
44
Name two extended spectrum penicillins
Ampicillin and anti-pseudomonas-carbenicillin
45
Name two extended spectrum penicillins with beta-lactamase inhibitors
Augmentin and Unasyn
46
Do penicillins have high or low toxicity in general?
Low
47
What is PCN V combined with?
K+ or Na+ to make a salt (K most common)
48
Is PCN V stable in gastric pH?
Yes, thus orally effective
49
High/low toxicity with PCN V?
Low
50
Narrow/broad spectrum with PCN V?
Narrow spectrum specific to oral microbes
51
PCN V has less activity against?
Gram negative bacilli compared with extended spectrum penicillins
52
Is PCN V cidal or static?
Cidal
53
Is PCN V expensive?
No
54
How is PCN G administered?
IV or IM only
55
Is PCN G stable in gastric contents?
No; no oral absorption
56
What three ways is PCN G formulated as?
Aqueous, Procaine, Benzathine
57
What is the drug of choice for most odontogenic infections?
Penicillin
58
What is the dosage for Penicillin?
2 g followed by 500 mg every 6 h
59
Parenteral dosage is given as?
Units
60
250 mg equals how many units?
400 K
61
In what two situations would you may need to decrease dose of PCN?
Renal compromise and infants
62
B-lactamase resistant PCNs are AKA?
"Anti-staph" PCNs (we as dentists are near going to write for these)
63
What's the prototype B-lactamase resistant PCN?
Methicillin ("Methicillin resistant staph" or MRSA)
64
What's the route of administration of Oxacillin?
Parenteral
65
What's the route of administration of Dicloxacillin?
Oral
66
Do B-lactamase resistant PCNs have more/less activity against oral bacteria?
Less
67
Are B-lactamase resistant PCNs expensive?
Yes
68
B-lactamase resistant PCNs are indicated only for proven?
Staphlyococcal infections
69
Extended spectrum PCNs make up what group?
Amoxicillin group
70
What's the route of administration of Ampicillin?
Parenteral
71
What's the route of administration of Amoxicillin?
Oral
72
Amoxicillin is indicated for what three conditions?
Otitis media, UTI, and SBE prophylaxis (and if C&S indicate use)
73
What may be considered for odontogenic infection?
Amoxicillin
74
Is Amoxicillin B-lactamase resistant?
No
75
For prophylaxis, would you give amoxicillin or penicillin?
Amoxicillin
76
For infection, would you give amoxicillin or penicillin?
Penicillin
77
Regarding SBE prophylaxis, does amoxicillin or PCN VK have more predictable absorption?
Amoxicillin
78
Regarding SBE prophylaxis, does amoxicillin or PCN VK have longer half life?
Amoxicillin
79
Regarding SBE prophylaxis, does amoxicillin or PCN VK have higher plasma concentration?
Amoxicillin
80
Do we use amoxicillin mainly because of broader spectrum?
No
81
Does amoxicillin or PCN have a better dosage regimen? What is it?
Amoxicillin; 500 mg q 8 h
82
Is Amoxicillin an acceptable alternative to PCN for odontogenic infection?
Yes
83
Extended spectrum PCNs are AKA?
Anti-pseudomonas PCNs
84
Name 3 extended spectrum PCNs
Carbenicillin, Ticarcillin, Piperacillin
85
Do extended spectrum PCNs have more/less activity against oral bacteria?
Less
86
Are extended spectrum PCNs indicated for any H&N infections as drug of choice?
No
87
Beta-lactamase combated by?
Increasing "R" chains or by competitive inhibition
88
What are the 3 currently available beta-lactam inhibitors?
Clavulonic acid, Sulbactam, Tazobcatam
89
What is Augmentin made up of?
Amoxicillin + Clavulonic acid
90
How is Augmentin administered?
Oral
91
What is Augmentin indicated for?
BITE WOUNDS, otitis, sinusitis (non-odontogenic), UTI
92
Is Augmentin the first line of defense?
No
93
What is Unasyn made up of?
Ampicillin + Sulbactam
94
How is Unasyn administered?
Parenteral
95
Unasyn has a similar spectrum as?
Augmentin
96
What is the drug of choice for serious infections being treated in a hospital setting (due to increasing resistance to PCN G)?
Unasyn
97
What is the main adverse effect of PCNs?
Allergy
98
What is the average occurrence of allergy to PCN?
2% average (1-10% occurrence)
99
Is allergic reaction to PCN usually fatal?
No
100
PCNs are antagonized by?
Bacteriostatic drugs
101
Decreased excretion of PCNs seen in?
Very young, old or compromised renal function
102
What is the most frequent drug of choice for odontogenic infection?
PCN V
103
What's a suitable alternative to PCN VK? Why?
Amoxicillin- better absorption and blood levels and dosing regimen
104
If significant anaerobic component, what drug is considered?
Metronidazole
105
Cephalosporins have 5 generations, based on?
Activity, not timing of release onto market
106
Cephalosporins have what configuration?
Beta-lactam
107
Cephalosporins have increased resistance to B-lactamase by addition of?
R groups
108
What are "custom" antibiotics?
Cephalosporins
109
Are cephalosporins cidal or static?
Cidal- cell wall inhibition
110
Do cephalosporins have low/high toxicity?
Low
111
Compared to PCN, cephalosporins have what kind of spectrum?
Extended
112
What forms of administration are available for cephalosporin?
Oral and parenteral
113
Compared to PCN, are cephalosporin more or less expensive
More expensive
114
What bacteria are we most worried about as dentists?
Streptococcus and oral anaerobes
115
What are the two first generation cephalosporin parenteral drugs?
Cephalothin (Keflin) and Cefazolin (Ancef, Kefzol)
116
What are the two first generation cephalosporin oral drugs?
Cephalexin (Keflex) and Cefadroxil (Duracef)
117
Cephalosporin first generation spectrum
Strep, staph (MSSA not MRSA), E. coli, proteus mirabilis, Klebsiella, oral anaerobes
118
What would you use for community acquired staph infection?
First generation ceph
119
What would you use for surgical wound prophylaxis with skin incision (parenteral)?
First generation ceph
120
What would you use for odontogenic infection (mild to moderate) in PCN-allergic patient (mild allergy)?
First generation ceph (oral)
121
What would you use for odontogenic infection (moderate to severe) in PCN-allergic patient (mild allergy)?
First generation cephalosporin (parenteral)
122
Do cephs get the same PAE as PCNs?
No- so longer duration of tx may be required for odontogenic infection in PCN allergic patient
123
What would you use for SBE and TJR prophylaxis?
First generation cephalosporin
124
What's the % incidence of PCN allergy?
5-8%
125
What % of PCN allergy will have ceph allergy?
1-10%
126
Ceph allergy predisposes to unknown incidence of?
PCN allergy (possibly high)
127
Avoid ceph in patient with?
Severe PCN allergy, probably ok if allergy is mild
128
Avoid PCN when what documented allergy is present?
Cephalosporin
129
Name 5 macrolide and ketolide antibiotics
Erythromycin and compounds, clarithromycin, azithromycin, dirithromycin, tolenaomycin
130
Macrolide irreversibly bind?
50S ribosomal unit
131
Macrolide inhibit?
RNA dependent protein synthesis
132
Do macrolide have a PAE?
Yes, significant PAE
133
How do macrolide lead to high levels at infection relative to blood cells?
Selective uptake by phagocytic cells which serve as repository
134
Clarithromycin is similar to?
Erythromycin
135
Compared to erythromycin, does clarithromycin have more/less resistance?
Less
136
Compared to erythromycin, does clarithromycin have better/worse H. influenza coverage?
Better
137
Clarithromycin has what type of dosing?
BID
138
Compared to erythromycin, does clarithromycin have more/less GI distress?
Less
139
What's the dosing regimen for clarithromycin?
250 mg BID, 1 h before or 2 h after eating
140
Compared to erythromycin, is clarithromycin more/less expensive?
More
141
Clarithromycin is indicated in what four situations?
SInus infection, mild-moderate odontogenic infection in PCN-allergic pt (azithromycin is better), SBE prophylaxis in PCN-allergic pt (as alt to clindamycin), pneumonia/bronchitis
142
Azithromycin is similar spectrum to clarithromycin but better for?
Strep and gram negative anaerobes
143
3 day course of azithromycin is as effective against odontogenic infection as how many days of augmentin?
7d
144
Indications for azithromycin?
Pneumonia/bronchitis, SBE prophylaxis
145
What's the dosing regimen of azithromycin?
Daily dosing/improved compliance (Z-pack)
146
Is azithromycin dosed around meals?
No
147
Does Azithromycin have more/less GI distress?
Less
148
Is azithromycin expensive?
Yes
149
What is the dosing of Azithromycin?
500 mg qd
150
What's the most significant adverse effect of macrolide?
Long Q-T interval/Torsades de Pointes (potentiated by certain other drugs)
151
GI distress with macrolide is worse with?
Erythromycin
152
Macrolide adverse effects
Ototoxicity, cholestatic jaundice, increased activity of Digitalis, potentiation of oral anticoagulants like Coumadin, myopathy in patients taking statins
153
What is the only lincosamide in use in the U.S.?
Clindamycin
154
How do lincosamides work?
Bind 50S ribosome leading to bacteriostatic inhibition of protein synthesis
155
Clindamycin spectrum
Strep, staph, actinomycetes, anaerobes
156
Is clindamycin static or cidal?
Static except at high doses
157
Does clindamycin penetrate bone?
Yes
158
Is clindamycin expensive?
Yes
159
Does clindamycin have high toxicity?
Higher than some- pseudomembranous colitis
160
Indications for clindamycin
Chronic recurrent infection, osteomyelitis, odontogenic infection in immunocompromised with severe PCN allergy
161
Dosing of clindamycin
300-900 mg q8h
162
Clindamycin indications for prophylaxis?
TJR and SBE prophylaxis in PCN allergic patient
163
Is metronidazole cidal or static?
Cidal
164
Is metronidazole expensive?
No
165
How does the oral dose or metro compare to parenteral?
Equivalent
166
Is metronidazole toxic?
Mild toxicity
167
What effect does metro have?
Disulfuram
168
Metro disrupts DNA in what environment?
Anaerobic (not shown to be teratogenic)
169
Metro indications
Chronic anaerobic infection
170
Metro has particularly effective what?
Bone penetration
171
Metro is used in combo with what for serious odontogenic infection?
PCN or Ceph
172
Dosing of metro
500 mg po/IV q8h
173
Tetracyclines are static or cidal?
Static
174
How do tetracyclines work?
30s ribosomal inhibition
175
Do tetracyclines have broad or narrow spectrum?
Broad
176
Do tetracyclines have high/low resistance?
High
177
Are tetracyclines expensive?
No
178
Tetracycline indications
Early adjunctive tx for peri-implantitis, resistant hospital acquired infections, heliobacter related gastric and peptic ulcer, topical therapy, dry socket prevention
179
Any indication for tetracycline for odontogenic infection?
No- may result in deformity of developing teeth
