Handout of Antibiotics in Dentistry

8/4/2019 Handout of Antibiotics in Dentistry

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Antibiotic Use In Dentistry

Kevin Nakagaki, D.D.S.

Director, Hospital Dental ClinicUniversity of Minnesota



Writing Prescriptions

Rx: Drug Name (can be generic) Unit Dose

(ex: Pen V-K 500 mg, Elixer, Sol’n)

Disp: # of pills, milliliters (ml)

Sig: Directions for use. q24h (daily), q12h, q8h, q6h, q4h,

prn pain, till gone

Refills__ Signature

DEA #



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)



Barry Brainfart Dental Clinic 666 Bite Me Ln

Crossbyte Falls, MN Ph: 555-YOU-HURT

Pt. Name: Address: DOB:

Rx: Date:

Disp:

Sig:

Refill____ Barry Brainfart, DDS

DEA:______________________



Antibiotic Strategies

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

Hard and Fast—Especially early. Why?

Use a loading dose to rapidly achieve

therapeutic blood levels. Avoid combinations of bacteriostatic and

bacteriocidal drugs.



Considerations

Gram Positive?

Gram Negative?

Mixed Infection? Anaerobes?



Discussion: Antibiotic Choice

Narrow Spectrum?

Extended/Broad Spectrum?

Designer Antibiotics?

Anaerobes? Consider if the infection ispresent > 3days or if no improvement.



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



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



Common Pathogens

Necrotic pulp and apical abscessesObligate anaerobic bacteria

Gram negative rodsPrevotella & 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 Pathogens

Periodontal DiseasesGingivitis

Fuso, strep, & actinomycetes

Adult peritonitisBacteroides, porphyomonas,peptostreptococcus & prevotellaAcute necrotizing ulcerative gingivitis

Spirochetes, prevotella, fusoLocalized juvenile periodontitis

Actinobacillus



Common Pathogens

Fungal InfectionsCandida 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 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



Lincosamides

Clindamycin (Cleocin)

– MOA: binds to the 50S ribosomal subunit and inhibitsprotein 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 onconcentration

– Spectrum:

Gram +, anaerobes, parasites

– Resistance

Enteroccocus

*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 theribosome

– 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, andspirochetes

– Resistance:

Widespread, cross resistance – PHOTO SENSITIVITY!!!



Nitroimidazoles

Metronidazole (Flagyl)

– MOA: reduced intermediate interacts andbreaks 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




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




ADA/AAOS Advisory

Statement

July 1997



AAOS Statement

Antibiotic prophylaxis is NOT

recommended for dental patientswith plates, pins, or screws, nor is

it routinely recommended forMOST dental patients with TOTAL

JOINT REPLACEMENTS.



AAOS recommendations

Prophylaxis recommended

– Total joint replacement within the last two yearsAND:

Compromised immune system OR

Type 1 DM OR

Previous prosthetic joint infections OR

MalnourishmentOR

Hemophilia



AAOS recommendations

Prophylaxis antibiotic recommendations – Same as AHA OR

– No specific regimen recommended

– Keflex is often the first drug of choice



Legal Considerations

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

Physician may not be aware of the advisorystatements or of the dental procedure to beperformed.

Vicarious Liability: ―The devil made me do it‖

―I forgot to take my antibiotic.‖

Documentation.



Legal Considerations

I forgot my antibiotics!

Animal studies have shown antibiotics areeffective up to 2 hours after the procedure.

Differentiate between prophylaxis vs.treatment of an early infection.

Take into consideration patient’s risk factors. Legal twists.



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, routeapplicability

Cost

– Brand name, length of course, alternatives?



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



Dental Infection

Acute — Rapid growth

< 3 daysChronic > 3 days

Pen VK 500mg q6h or

Amox 500mg q8h orCephalosporin

Allergic to PCN

Clindamycin 300mg q8h or

Cephalosporin (check allergic Rxn) or

Azith or Clarithromycin

Think Anaerobes

Add Metronidazole 250-500mgTo PCN, Amox, or Ceph

Clindamycin 300mg q8h

Documents

Handout of Antibiotics in Dentistry