Antibiotic Use In DentistryAntibiotic Use In Dentistry

Writing PrescriptionsWriting Prescriptions

Rx: Drug Name (can be generic) Unit DoseRx: Drug Name (can be generic) Unit Dose(ex: Pen V-K 500 mg, Elixer, Sol’n)(ex: Pen V-K 500 mg, Elixer, Sol’n)

Disp: # of pills, milliliters (ml)Disp: # of pills, milliliters (ml)

Sig: Directions for use. q24h (daily), q12h, q8h, q6h, q4h, Sig: Directions for use. q24h (daily), q12h, q8h, q6h, q4h, prn pain, till goneprn pain, till gone

Refills__Refills__ SignatureSignature DEA #DEA #

General RulesGeneral Rules

Write Legibly!!Write Legibly!! Remember your audience (Generally non-docs) Remember your audience (Generally non-docs)

this will improve compliance.this will improve compliance. Preferable to order specific hourly dosage time Preferable to order specific hourly dosage time

(q12h vs. bid, q8h vs. tid, etc.)(q12h vs. bid, q8h vs. tid, etc.) Sig: Specify # of pills to take each doseSig: Specify # of pills to take each dose Prescribe an endpoint. (prn pain, till gone)Prescribe an endpoint. (prn pain, till gone)

Barry Brainfart Dental Clinic 666 Bite Me LnCrossbyte Falls, MN Ph: 555-Y OU-HURTPt. Name: Address: DOB:

Rx: Date:

Disp:

Sig:

Refill____ Barry Brainfart, DDS

DEA:______________________

Antibiotic StrategiesAntibiotic Strategies

Cardinal Rules: 1) Use the right drug. Cardinal Rules: 1) Use the right drug. 2) Use the right dose. 3) Use the correct 2) Use the right dose. 3) Use the correct dosing schedule. 4) Correct duration.dosing schedule. 4) Correct duration.

Hard and Fast—Especially early. Why?Hard and Fast—Especially early. Why? Use a loading dose to rapidly achieve Use a loading dose to rapidly achieve

therapeutic blood levels.therapeutic blood levels. Avoid combinations of bacteriostatic and Avoid combinations of bacteriostatic and

bacteriocidal drugs.bacteriocidal drugs.

ConsiderationsConsiderations

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

Discussion: Antibiotic ChoiceDiscussion: Antibiotic Choice

Narrow Spectrum?Narrow Spectrum? Extended/Broad Spectrum?Extended/Broad Spectrum? Designer Antibiotics?Designer Antibiotics? Anaerobes? Consider if the infection is Anaerobes? Consider if the infection is

present > 3days or if no improvement.present > 3days or if no improvement.

Narrow Spectrum AntibioticsNarrow Spectrum Antibiotics

Specific for the pathogen.Specific for the pathogen. Fewer disturbances of non-pathogenic Fewer disturbances of non-pathogenic

bacteria.bacteria. Fewer side effects.Fewer side effects. Rapid response for sensitive organisms.Rapid response for sensitive organisms. Ex: Pen VK, Pen G, ErythromycinEx: Pen VK, Pen G, Erythromycin

Broad Spectrum AntibioticsBroad Spectrum Antibiotics

Affects both Gram + and Gram – bacteria, Affects both Gram + and Gram – bacteria, better for mixed infections.better for mixed infections.

May give up some effectiveness for Gram + May give up some effectiveness for Gram + to gain effectiveness for Gram -. to gain effectiveness for Gram -.

Examples: Amoxicillin, AmpicillinExamples: Amoxicillin, Ampicillin

Common PathogensNecrotic pulp and apical abscesses

Obligate anaerobic bacteriaGram negative rods

Prevotella & porphyomonas spp.Fusobacterium spp.Campylobacter rectus

Gram positive rodsEubacterium spp.Actinomycetes spp.

Gram positive cocciPeptostreptococcus spp.

Facultative anaerobic bacteriaGram positive cocci

Strep and Entercoccus spp.

Common PathogensCommon Pathogens

Periodontal Diseases Periodontal Diseases GingivitisGingivitis

Fuso, strep, & actinomycetesFuso, strep, & actinomycetesAdult peritonitisAdult peritonitis

Bacteroides, porphyomonas, Bacteroides, porphyomonas, peptostreptococcus & prevotellapeptostreptococcus & prevotellaAcute necrotizing ulcerative gingivitisAcute necrotizing ulcerative gingivitisSpirochetes, prevotella, fusoSpirochetes, prevotella, fuso

Localized juvenile periodontitisLocalized juvenile periodontitisActinobacillusActinobacillus

Common PathogensCommon Pathogens

Fungal InfectionsFungal InfectionsCandida spp.Candida spp.Mucorales spp.Mucorales spp.

Let’s 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 +

Antibiotic ChoicesAntibiotic Choices

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

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 (>80%)

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)

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

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

Cephalosporins

Cephalexin (Keflex)– Bactericidal– Spectrum:

Gram +

– Resistance: Methicillin resistant gram +

– Low cross sensitivity with PCN

LincosamidesLincosamides

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

Lincosamides

Clindamycin– Bactericidal or static depending on

concentration– Spectrum:

Gram +, anaerobes, parasites

– Resistance Enteroccocus

*Clostridium diff. pseudomembranous colitis!!*Clostridium diff. pseudomembranous colitis!!

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

Macrolides

Azithromycin, clarithromycin– Bactericidal– Spectrum:

Gram +, gram -, anaerobes

– Resistance: B. fragilis, and strep pneumo

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

Tetracyclines

Doxycycline– Bacteriostatic– Spectrum:

Broad, Gram +, -, anaerobes, aerobes, and spirochetes

– Resistance: Widespread, cross resistance

– PHOTO SENSITIVITY!!!

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

Nitroimidazoles

Metronidazole– Bactericidal– Spectrum:

Gram - anaerobes

– Resistance: Rare, H. Pylori?

– Unpleasant metallic taste

Fluoroquinolones

Ciprofloxacin (Cipro)– MOA: Inhibition of DNA gyrase, and Topo II– Dose: 250-500 mg qd x 7-10 days– Contraindications: <18 yrs old, pregnancy– Adverse events: spontaneous tendon rupture– Drug interactions: probenacid, warfarin– Pregnancy category C

Fluoroquinolones

Ciprofloxacin– Bactericidal– Spectrum:

Very broad except B. frag

– Resistance: MRSA, MRSE

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

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

ADA/AAOS Advisory ADA/AAOS Advisory StatementStatement

July 1997July 1997

AAOS StatementAAOS Statement

Antibiotic prophylaxis is Antibiotic prophylaxis is NOTNOT recommended for dental patients recommended for dental patients with with plates, pins, or screws,plates, pins, or screws, nor is nor is

it routinely recommended for it routinely recommended for MOSTMOST dental patients with dental patients with TOTAL TOTAL

JOINT REPLACEMENTS.JOINT REPLACEMENTS.

AAOS recommendationsAAOS 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

AAOS recommendations

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

Legal ConsiderationsLegal Considerations

The dentist may not be aware of the The dentist may not be aware of the patient’s medical condition.patient’s medical condition.

Physician may not be aware of the advisory Physician may not be aware of the advisory statements or of the dental procedure to be statements or of the dental procedure to be performed.performed.

Vicarious Liability: “The devil made me do it”Vicarious Liability: “The devil made me do it” ““I forgot to take my antibiotic.”I forgot to take my antibiotic.” Documentation.Documentation.

Legal ConsiderationsLegal Considerations

I forgot my antibiotics!I forgot my antibiotics! Animal studies have shown antibiotics are Animal studies have shown antibiotics are

effective up to 2 hours after the procedure.effective up to 2 hours after the procedure. Differentiate between prophylaxis vs. Differentiate between prophylaxis vs.

treatment of an early infection.treatment of an early infection. Take into consideration patient’s risk Take into consideration patient’s risk

factors.factors. Legal twists.Legal twists.

In Summary….In Summary….

Principles of Antibiotic Therapy

Therapeutic effectiveness– Clinical indications

Pharmcodynamics, pharmacokinetics

– Age and extent of infection

Patient factors

Age, allergies, compliance, pregnancy risk Patient function

– Renal, hepatic, immunosuppresion, route applicability

Cost– Brand name, length of course, alternatives?

Dental Infection

Acute—Rapid growth< 3 days

Chronic > 3 days

Pen VK 500mg q6h orAmox 500mg q8h or

Cephalosporin

Allergic to PCN

Clindamycin 300mg q8h orCephalosporin (check allergic Rxn) or

Azith or Clarithromycin

Think AnaerobesAdd Metronidazole 250-500mg

To PCN, Amox, or Ceph

Clindamycin 300mg q8h