LO 11 Flashcards

Antibiotics

1
Q

Describe the progression of dental infections

A
  1. Dental infections often follow similar pathways from beginning to end
  2. The organisms initially responsible for a dental infection are primarily gram-positive cocci
  3. After a short time, the gram-positive infection begins to include a variety of both gram-positive and gram-negative anaerobic organisms; this is termed a mixed infection
  4. Over time, the proportion of organisms that are anaerobic increases until it consists of predominately anaerobic flora
  5. The choice of antibiotics for an infection depends on where it is in its evolution
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2
Q

What are the factors that determine the likelihood of a microorganism causing an infection

A
  1. Disease-producing power of the microorganism (virulence)
  2. Number of organisms present (inoculum)
  3. Resistance of the host (immunologic response)
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3
Q

__________ involves exposing the organism to test antibiotics and determining whether the organism is sensitive or resistant

A

Sensitivity testing

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4
Q

___________ and ____________ is the only way to be sure a drug will kill or inhibit the growth of the infecting microorganisms

A
  1. Culturing
  2. Sensitivity testing
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5
Q

The best defense against a pathogen is __________

A

host response

*When this defense is lacking, the need for antimicrobial agents is more pressing

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6
Q

What is the rule for antimicrobial therapy in dentistry?

A
  1. No simple rule has been developed to determine whether antimicrobial therapy is needed in dentistry; many infections do not require it
  2. Most patients, without immune function deficiencies, in whom drainage can be obtained, do not need antibiotics to manage their dental infections
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7
Q

Define Antibacterial agents

A

Substances that destroy or suppress the growth or multiplication of bacteria

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8
Q

Define Antibiotic agents

A

Chemical substances produced by microorganisms that have the capacity, in dilute solutions, to destroy or suppress the growth or multiplication of organisms or prevent their action

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9
Q

Define Bactericidal

A
  1. Ability to kill bacteria
  2. Irreversible; if the bacteria are removed from the drug, they do not live
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10
Q

Define Bacteriostatic

A
  1. Ability to inhibit or retard the multiplication or growth of bacteria
  2. Reversible; if the bacteria are removed from the agent, they are able to grow and multiply
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11
Q

Define resistance

A

The natural or acquired ability of an organism to be immune to or resist the effects of an antiinfective agent

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12
Q

Define Superinfection/suprainfection

A

Infection caused by proliferation of microorganisms different from those causing the original infection

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13
Q

What are the indications for antibiotics in dentistry?

A
  1. Therapeutic (abscess)
  2. Pre-medication** – antibiotic prophylaxis (no current infection)
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14
Q

List the general considerations for antibiotics

A
  1. only consider AB if patient is immune compromised or lymphadenopathy is detected in a healthy client.
  2. course of Tx should be 1 week until finished
  3. Minimum 9 days between appt’s pre-meds are required
  4. Cross-allergenicity within each group
  5. Increase AB resistance if taken too often / not completed Tx course
  6. Cost !!
  7. Rx the narrowest spectrum as possible.
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15
Q

List the general adverse reactions to antibiotics

A
  1. Superinfection/suprainfection
  2. AB can decrease efficacy of oral contraceptives
  3. AB can increase warfarin efficacy = warfarin toxicity
  4. G.I distress - pseudomembranous colitis (c.diff), vomiting, upset GI, etc.
  5. During pregnancy, only penicillin + clindamycin are “safe”
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16
Q

List the 6 most common antibiotic groups

A
  1. Penicillin (penicillin & ampicillins/Amoxycillin)
  2. Macrolides (Erythromycin, azithromycin, & clarithromycin)
  3. Tetracycline (Tetracycline, Minocycline, & Doxycycline/Periostat)
  4. Clindamycin/Cleocin
  5. Cephalosporin
  6. Nitroimidazoles (metronidazole/Flagyl)
17
Q

Which antibiotics belong to the group B-lactams?

A
  1. Penicillin
  2. Cephalosporin
18
Q

What is the most commonly used AB in dentistry?

A

Penicillin

19
Q

What is the most commonly used AB in case of Penicillin allergy?

A

azithromycin and clarithromycin

20
Q

What are the 2 routes of administration for penicillin?

A
  1. Pen V - Oral
  2. Pen G - I.V.
21
Q

Describe the profile of Penicillins

A
  1. Affect aerobic bacteria (good for early stages of infection)
  2. Used for treatment of periapical abscess
  3. Bactericidal - Penicillin destroys cell wall integrity and lead to lysis
  4. Adverse reactions - allergy ** 5-10%
22
Q

Give an example of a prescription for prophylactic penicillin

A

Rx: Amox. 500mg tab
Disp: 4 tabs
(total 2g dose)
Sig: take all 4 tabs,1hr prior to apt

23
Q

Describe the profile of Macrolides

A
  1. Older drug - Erythromycin
  2. Newer meds - azithromycin and clarithromycin (have less adverse reactions)
  3. Narrow spectrum for Gram positive
  4. Bacteriostatic
  5. Adverse reactions - major GI problems; Increase warfarin toxicity
  6. For pre-meds, take 500mg 30mins-1hr before appt
24
Q

Describe the profile of Tetracycline

A
  1. Tetracycline (Tetracycline, Minocycline, & Doxycycline/Periostat)
  2. 20mg bid for >9mth for certain perio cases (not for adult perio cases
  3. Broad spectrum G+/G-
  4. Bacteriostatic
  5. Adverse reactions - stained teeth, Black bone staining with minocycline, exaggerated sunburn due to photosensitivity
  6. Strong affinity for calcium
    DO NOT TAKE WITH Ca/Al/Mg containing foods or drugs: dairy and antacids (avoid 2h before and after)
25
Q

Describe the profile of Cephalosporin

A
  1. First generation - cefalexin=Keflex
  2. Second generation - cefaclor (Ceclor)
  3. Third generation - cefixime (Suprax)
  4. Cross allergenicity with pencillins (it is the expensive cousin)
  5. Similar profile to pens in terns if narrow spectrum
26
Q

Describe the profile of Clindamycin

A
  1. AB group - Lincosamides
  2. Trade name - Cleocin
  3. Broad spectrum G+/G-
  4. Bacteriostatic
  5. Adverse reactions - pseudomembranous colitis (c.diff) :Characterized by severe, persistent diarrhea and the passage of blood and mucus
  6. Clindamycin is no longer recommended for antibiotic prophylaxis for dental/dental hygiene procedures. It may cause more frequent and severe reactions than other antibiotics used for antibiotic prophylaxis.
26
Q

Describe the profile of Nitroimidazoles

A
  1. metronidazole= Flagyl
  2. Works on anaerobic bacteria
  3. Used for TX of PERIO abscess - Aa bacteria - Gram negative IMPORTANT
  4. Broad spect G+/G-
  5. Bactericidal
  6. Adverse reactions - metallic taste, xerostomia, CNS effects in breast milk
  7. Drug interactions - Ԑt-OH (none while taking AB) similar to disulfiram (Antabuse) Symptoms include nausea, abdominal cramps, flushing, vomiting, and headache
27
Q

List the reasons an antibiotic may not be effective

A
  1. Patient compliance: they may not be taking the antibiotic
  2. Ineffective antibiotic: may not be effective against the organism producing the infection
  3. Poor debridement: dead tissue, purulent exudate, or foreign bodies were not removed from site of infection
  4. Resistant organism: the organism may be resistant to the antibiotic chosen
  5. Concentration did not reach the site of infection
  6. Host defenses are inadequate
28
Q

Which cardiac conditions require antibiotic prophylaxis?

A
  1. prosthetic valves
  2. previous bacterial endocarditis
  3. congenital heart disease - unrepaired cyanotic CHD, including palliative shunts and conduits; repaired CHD defects during the first 6 month after the procedure; repaired CHD with residual defects
  4. cardiac transplant that developed valve pathology
29
Q

Is antibiotic prophylaxis required for total joint replacement?

A

Not any longer!

Found to be more of a risk than a help for these patients

30
Q

What Non-cardiac Medical Conditions require antibiotic prophylaxis?

A

Patients with noncardiac medical conditions may also require prophylactic antibiotic coverage before dental procedures, “but lack of agreement among practitioners for these situations causes confusion”

31
Q

What dental procedures require antibiotic prophylaxis?

A
  1. Extractions
  2. Endodontic surgery or instrumentation beyond apex
  3. Periodontal surgery, scaling, root planing and probing
  4. Subgingival placement of antibiotic fibers and strips
  5. Initial placement of orthodontic bands, not for brackets
  6. Intraligamentary LA injection
  7. Prophylactic cleaning of teeth or implants with anticipated bleeding

Anything that might cause bleeding where the bacteria is (around the teeth)

32
Q

How soon should we schedule appointments if patient requires antibiotic prophylaxis?

A
  1. Need to wait to reduce chances of bacterial resistance
  2. Best waiting period is 9 days between (not including) appt days (aka on the 10th day after the appt)