1. Antibiotic Use In Dentistry
Dr. Soukaina Ryalat

2. 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 #

3. Most antibiotics have 2 names, the trade or brand name, created by the drug company that manufactures the drug, and a generic name, based on the antibiotic's chemical structure or chemical class. Trade names such as Keflex and Zithromax are capitalized. Generics such as cephalexin and azithromycin are not capitalized.

5. Antibiotics have 2 names :
Generic name ; based on chemical constituents of the drug & it is not capitalized .
Trade name ; created by the drug company & it is capitalized.
Examples :
generic name: cefalexin ( 1st generation cephalosporin)
Trade name: Sporidex produced by Ranbaxy company & Keflex by Lilly company.

6. Antibiotic Strategies
Cardinal Rules: 1) Use the right drug ) Use the right dose. 3) Use the correct dosing schedule. 4) Correct duration.
Use a loading dose to rapidly achieve therapeutic blood levels.
Avoid combinations of bacteriostatic and bacteriocidal drugs.

7. Most odontogenic infections are caused by mixed organisms .
Rules for prescribing antibiotics:
Use the write drug
Use the write dose
Use the correct dose schedule & correct duration.
Most odontogenic infections are caused by mixed organisms .
When we prescribe antibiotic we have to reach MIC ( Minimum Inhibitory Concentration: is the smallest concentration of an antimicrobial needed to stop bacterial growth ).
Most of the drugs take their action within 2-3 days but we give an extra 2 days to make sure that the patient has taken the drug the right way & the desired effect has been achieved ( patient compliance).

8. Considerations Gram Positive? Gram Negative? Mixed Infection?
Anaerobes?

9. Broad Spectrum Antibiotics
Affects both Gram + and Gram – bacteria, better for mixed infections.
Examples: Amoxicillin, Ampicillin

10. 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.

11. Facultative anaerobic bacteria
Gram positive cocci
Peptostreptococcus spp.
Facultative anaerobic bacteria
Strep and Entercoccus spp.

12. Common Pathogens
Periodontal Diseases Gingivitis Fuso, strep, & actinomycetes
Bacteroides, porphyomonas, peptostreptococcus & prevotella Acute necrotizing ulcerative gingivitis Spirochetes, prevotella, fuso
Localized juvenile periodontitis Actinobacillus

13. Antibiotic 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

14. Transposon (transduction and transformation)
Phage mediated
Clinically important for Gram +

15. Antibiotic Choices

16. ß-Lactams Natural penicillins Pen V and Pen G
MOA (mechanism of action): Inhibit cell wall synthesis
Dose: mg qid x 7-10 days
Contraindications:
Allergies
Poor renal fxn
Adverse events: GI upset
Drug interactions: oral contraceptives
Pregnancy category B

17. ß-Lactams Natural penicillins Pen V and Pen G Bactericidal
Allergic reaction: rare (4 per 100,000)
Spectrum:
Strep, staph, enterococcus, neiseria, treponema, listeria
Resistance:
Mostly staph (>80%)

18. ß-Lactams Amino-penicillins Amoxicillin, ampicillin
MOA: Inhibit cell wall synthesis
Dose: 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)

19. 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

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

21. Cephalosporins Cephalexin (Keflex) Bactericidal Spectrum: Resistance:
Gram +
Resistance:
Methicillin resistant gram +
Low cross sensitivity with PCN

22. Cephalosporins, 1st generation Cefadroxil DURICEF Cefazolin ANCEFKEFZOL Cephalexin KEFLEX Mainly skin and soft-tissue infections
Gastrointestinal upset and diarrhea NauseaAllergic reactions

23. Cephalosporins, 2nd generation CefaclorCefoxitin MEFOXIN Cefprozil CEFZIL Cefuroxime CEFTINZINACEF Loracarbef
Some respiratory infections and, for cefoxitin MEFOXIN , abdominal infectionss
Gastrointestinal upset and diarrheaNauseaAllergic reactions

24. Cephalosporins, 3rd generation Cefixime SUPRAX Cefdinir OMNICEF Cefditoren SPECTRACEF CefoperazoneCefotaxime CLAFORAN Cefpodoxime VANTIN

25. Ceftazidime FORTAZTAZICEF Ceftibuten CEDAX Ceftizoxime CEFIZOX Ceftriaxone ROCEPHIN

26. 3d generation
Given by mouth: Broad coverage of many bacteria for people with mild-to-moderate infections, including skin and soft-tissue infections.
Given by injection: Serious infections (such as meningitis or infections acquired in a hospital)

27. Cephalosporins, 4th generation Cefepime MAXIPIME Serious infections (including Pseudomonas infections), particularly in people with a weakened immune system and infections due to susceptible bacteria resistant to other antibiotics

28. Cephalosporins, 5th generation Ceftobiprole
Complicated skin infections, including foot infections in people with diabetes, due to susceptible bacteria, such as Escherichia coli, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA)

29. Lincosamides Clindamycin (Cleocin)
MOA: binds to the 50S ribosomal subunit and inhibits protein synthesis
Dose: mg 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

30. Lincosamides Clindamycin
Bactericidal or static depending on concentration
Spectrum:
Gram +, anaerobes, parasites
Resistance
Enteroccocus
*Clostridium diff. pseudomembranous colitis!!

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

32. Macrolides Azithromycin, clarithromycin Bactericidal Spectrum:
Gram +, gram -, anaerobes
Resistance:
B. fragilis, and strep pneumo

33. 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

34. Tetracyclines Doxycycline Bacteriostatic Spectrum: Resistance:
Broad, Gram +, -, anaerobes, aerobes, and spirochetes
Resistance:
Widespread, cross resistance
PHOTO SENSITIVITY!!!

35. Nitroimidazoles Metronidazole (Flagyl)
MOA: reduced intermediate interacts and breaks the bacterial or parasitic DNA
Dose: mg q 6-8 h x 7-10 days
Precautions : poor hepatic fxn
Adverse events: GI upset.
Drug interactions: warfarin, Li+
Pregnancy category D

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

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

38. Fluoroquinolones Ciprofloxacin Bactericidal Spectrum: Resistance:
Very broad except B. frag
Resistance:
MRSA, MRSE

39. Antifungals Nystatin MOA: inhibit cell wall synthesis
Dose: 5 ml swish and swallow q 4 h x d
GI upset
Drug interactions: minor
Pregnancy category C

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

41. ADA Regulations

42. 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.

43. 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

44. Prophylaxis antibiotic recommendations
No specific regimen recommended
Keflex is often the first drug of choice

45. Legal Considerations
The dentist may not be aware of the patient’s medical condition.
Physician may not be aware of the advisory statements or of the dental procedure to be performed.
Documentation.

46. Pharmaceutical pregnancy categories :
Category A :
Adequate & well controlled studies on both humans & animals have failed to demonstrate risk to the fetus.
Category B :
Animal reproduction studies have failed to demonstrate a risk to the fetus & there are no adequate & well controlled studies in pregnant women.
Category C :
Animal reproduction studies have shown an adverse effect on the fetus & there are no adequate & well controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risk.

47. In Summary….

48. Principles of Antibiotic Therapy
Therapeutic effectiveness
Clinical indications
Pharmcodynamics, pharmacokinetics
Age and extent of infection

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

50. Cost of Therapy $ (~10 Days) Generic if Available
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