Antibiotic Use In Dentistry

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Antibiotic Use In Dentistry

• Kevin Nakagaki, D.D.S.
• Director, Hospital Dental Clinic
• University of Minnesota

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Writing Prescriptions

• Rx Drug Name (can be generic) Unit Dose
• (ex Pen V-K 500 mg, Elixer, Soln)
• Disp of pills, milliliters (ml)
• Sig Directions for use. q24h (daily), q12h,
  q8h, q6h, q4h,
• prn pain, till gone
• Refills__ Signature
• DEA

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General Rules

• Write Legibly!!
• Remember your audience (Generally non-docs) this
  will improve compliance.
• Preferable to order specific hourly dosage time
  (q12h vs. bid, q8h vs. tid, etc.)
• Sig Specify of pills to take each dose
• Prescribe an endpoint. (prn pain, till gone)

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Antibiotic Strategies

• Cardinal Rules 1) Use the right drug. 2)
  Use the right dose. 3) Use the correct dosing
  schedule. 4) Correct duration.
• Hard and FastEspecially early. Why?
• Use a loading dose to rapidly achieve therapeutic
  blood levels.
• Avoid combinations of bacteriostatic and
  bacteriocidal drugs.

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Considerations

• Gram Positive?
• Gram Negative?
• Mixed Infection?
• Anaerobes?

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Discussion Antibiotic Choice

• Narrow Spectrum?
• Extended/Broad Spectrum?
• Designer Antibiotics?
• Anaerobes? Consider if the infection is present gt
  3days or if no improvement.

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Narrow Spectrum Antibiotics

• Specific for the pathogen.
• Fewer disturbances of non-pathogenic bacteria.
• Fewer side effects.
• Rapid response for sensitive organisms.
• Ex Pen VK, Pen G, Erythromycin

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Broad Spectrum Antibiotics

• Affects both Gram and Gram bacteria, better
  for mixed infections.
• May give up some effectiveness for Gram to gain
  effectiveness for Gram -.
• Examples Amoxicillin, Ampicillin

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Common Pathogens

• Necrotic pulp and apical abscesses
• Obligate anaerobic bacteria
• Gram negative rods
• Prevotella porphyomonas spp.
• Fusobacterium spp.
• Campylobacter rectus
• Gram positive rods
• Eubacterium spp.
• Actinomycetes spp.
• Gram positive cocci
• Peptostreptococcus spp.
• Facultative anaerobic bacteria
• Gram positive cocci
• Strep and Entercoccus spp.

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Common Pathogens

• Periodontal Diseases Gingivitis Fuso, strep,
  actinomycetesAdult peritonitis
• Bacteroides, porphyomonas, peptostreptococcus
  prevotellaAcute necrotizing ulcerative
  gingivitisSpirochetes, prevotella, fuso
• Localized juvenile periodontitisActinobacillus

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Common Pathogens

• Fungal Infections Candida spp. Mucorales spp.

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Lets Talk About Resistance

• Three main types
• Chromosome mediated
• Spontaneous mutations
• Non-major form of drug resistance
• Rarely lead to complete resistance
• Plasmid mediated (conjugation)
• VERY important from clinical standpoint
• Mostly gram negs
• Mediate resistance to multiple drugs
• High transfer rate from cell to cell
• Transposon (transduction and transformation)
• Phage mediated
• Clinically important for Gram

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Antibiotic Choices
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ß-Lactams

• Natural penicillins
• Pen VK and Pen G
• MOA Inhibit cell wall synthesis
• Dose 250-500 mg qid x 7-10 days
• Contraindications
• Allergies
• Poor renal fxn
• Adverse events GI upset
• Drug interactions oral contraceptives
• Pregnancy category B

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ß-Lactams

• Natural penicillins
• Pen VK and Pen G
• Bactericidal
• Allergic reaction rare (4 per 100,000)
• Spectrum
• Strep, staph, enterococcus, neiseria, treponema,
  listeria
• Resistance
• Mostly staph (gt80)

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ß-Lactams

• Amino-penicillins
• Amoxicillin, ampicillin
• MOA Inhibit cell wall synthesis
• Dose 250-500 mg q 8 h x 7-10 days
• Contraindications
• Allergies
• Poor renal fxn
• Adverse events GI upset
• Drug interactions oral contraceptives
• Amoxicillin and clavulanic acid (Augmentin)

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ß-Lactams

• Amino-penicillins
• Amoxicillin, ampicillin
• Bactericidal
• ampicillin rash (4-10)
• Spectrum
• Strep, staph, enterococcus, neiseria, treponema,
  listeria, E. coli, proteus, H. Flu, shigella,
  salmonella
• Resistance
• Entero, citro, serratia, proteus vulagris,
  provedincia, morganella, pseudomonas aeriginosa,
  acinetobacter

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Cephalosporins

• Cephalexin (Keflex)
• MOA Inhibit cell wall synthesis
• Dose 250-1000mg q 6 h x 7-10 days
• Contraindications
• Allergies
• Poor renal fxn
• Adverse events mild GI
• Drug interactions probenecid
• Pregnancy category B

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Cephalosporins

• Cephalexin (Keflex)
• Bactericidal
• Spectrum
• Gram
• Resistance
• Methicillin resistant gram
• Low cross sensitivity with PCN

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Lincosamides

• Clindamycin (Cleocin)
• MOA binds to the 50S ribosomal subunit and
  inhibits protein synthesis
• Dose 100-450mg q 6 h x 7-10 days
• Precautions
• Poor hepatic fxn
• Adverse events GI upset, pseudomembraneous
  colitis
• Drug interactions neuromuscular blocking agents
• Pregnancy category B

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Lincosamides

• Clindamycin
• Bactericidal or static depending on concentration
• Spectrum
• Gram , anaerobes, parasites
• Resistance
• Enteroccocus
• Clostridium diff. pseudomembranous colitis!!

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Macrolides

• Azithromycin (Zithromax), clarithromycin (Biaxin)
• MOA bind to the 23S rRNA in the 50S subunit
  ribosome
• Dose 250-500 mg/day x 5-10 days
• Precautions
• Poor hepatic fxn
• Adverse effects GI
• Drug interactions Cytochrome P-450 (Remember
  Seldane?)
• Pregnancy category B

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Macrolides

• Azithromycin, clarithromycin
• Bactericidal
• Spectrum
• Gram , gram -, anaerobes
• Resistance
• B. fragilis, and strep pneumo

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Tetracyclines

• Doxycycline (Vibramycin)
• MOA inhibit protein synthesis by preventing
  aminoacyl transfer RNA from entering the acceptor
  sites on the ribosome
• Dose 100mg qd-bid x 7-14 days
• Contraindications
• Food
• pregnancy
• Adverse events GI
• Drug interactions anti-epileptics
• Pregnancy category D

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Tetracyclines

• Doxycycline
• Bacteriostatic
• Spectrum
• Broad, Gram , -, anaerobes, aerobes, and
  spirochetes
• Resistance
• Widespread, cross resistance
• PHOTO SENSITIVITY!!!

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Nitroimidazoles

• Metronidazole (Flagyl)
• MOA reduced intermediate interacts and breaks
  the bacterial or parasitic DNA
• Dose 250-1000 mg q 6-8 h x 7-10 days
• Precautions poor hepatic fxn
• Adverse events HA, N/V/D
• Drug interactions EtOH, warfarin, Li
• Pregnancy category D

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Nitroimidazoles

• Metronidazole
• Bactericidal
• Spectrum
• Gram - anaerobes
• Resistance
• Rare, H. Pylori?
• Unpleasant metallic taste

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Fluoroquinolones

• Ciprofloxacin (Cipro)
• MOA Inhibition of DNA gyrase, and Topo II
• Dose 250-500 mg qd x 7-10 days
• Contraindications lt18 yrs old, pregnancy
• Adverse events spontaneous tendon rupture
• Drug interactions probenacid, warfarin
• Pregnancy category C

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Fluoroquinolones

• Ciprofloxacin
• Bactericidal
• Spectrum
• Very broad except B. frag
• Resistance
• MRSA, MRSE

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Antifungals

• Nystatin
• MOA inhibit cell wall synthesis
• Dose 5 ml swish and swallow q 4 h x 10-14 d
• GI upset
• Drug interactions minor
• Pregnancy category C

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Antifungals

• Clotrimazole (Mycelex), ketoconazole (Nizoral),
  fluconazole (Diflucan)
• MOA inhibit cell wall synthesis
• Dose 200-800 mg qd x up to 12 months
• GI upset
• Drug interactions major p-450 enzyme inhibitor,
  interactions with many drugs
• Pregnancy category C

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ADA/AAOS Advisory Statement

• July 1997

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AAOS Statement

• Antibiotic prophylaxis is NOT recommended for
  dental patients with plates, pins, or screws, nor
  is it routinely recommended for MOST dental
  patients with TOTAL JOINT REPLACEMENTS.

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AAOS recommendations

• Prophylaxis recommended
• Total joint replacement within the last two years
  AND
• Compromised immune system OR
• Type 1 DM OR
• Previous prosthetic joint infections OR
• Malnourishment OR
• Hemophilia

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AAOS recommendations

• Prophylaxis antibiotic recommendations
• Same as AHA OR
• No specific regimen recommended
• Keflex is often the first drug of choice

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Legal Considerations

• The dentist may not be aware of the patients
  medical condition.
• Physician may not be aware of the advisory
  statements or of the dental procedure to be
  performed.
• Vicarious Liability The devil made me do it
• I forgot to take my antibiotic.
• Documentation.

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Legal Considerations

• I forgot my antibiotics!
• Animal studies have shown antibiotics are
  effective up to 2 hours after the procedure.
• Differentiate between prophylaxis vs. treatment
  of an early infection.
• Take into consideration patients risk factors.
• Legal twists.

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In Summary.
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Principles of Antibiotic Therapy

• Therapeutic effectiveness
• Clinical indications
• Pharmcodynamics, pharmacokinetics
• Age and extent of infection

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Patient factors

• Age, allergies, compliance, pregnancy risk
• Patient function
• Renal, hepatic, immunosuppresion, route
  applicability
• Cost
• Brand name, length of course, alternatives?

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Cost
Drug Name Cost of Therapy (10 Days) Generic if Available
Pen VK 6.81
Amoxicillin 8.41
Ampicillin 12.45
Cephalexin 15.65
Clindamycin 38.45
Azithromycin 41.52
Clarithromycin 74.45
Augmentin 76.82
Doxycycline 5.15
Metronidazole 9.65
Ciprofloxacin 76.65
Nystatin 9.86
Clotrimazole 97.05
Ketoconazole 30.69
Fluconazole 116.25
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