Transcript
7
Antibacterial Agents
Educational Objectives
After reading this chapter, the reader should be able to:
1. List the classifications of the different antibiotics including penicillins, cephalosporins, tetracyclines, macrolides, fluoroquinolones, and nitroimidazoles.
2. Understand the concept of bactericidal versus bacteriostatic antibiotics.
3. Describe the adverse effects of the various antibiotics.
4. Explain the use of antibiotics in periodontics, implants, oral surgery, and endodontics.
5. Discuss the rationale for use of topical agents used in dentistry.
6. Discuss the characteristics of the bacterium that causes tuberculosis.
7. List the various antimycobacterial drugs.
8. Discuss the dental adverse effects of antimycobacterial drugs.
9. Explain the role of interferons and herbal supplements in the treatment of hepatitis C.
Lecture Outline
I. Antimicrobial Activity
A. Louis Pasteur.
B. Natural antibiotics.
C. Synthetic antibiotics.
II. Actions of Antibacterial Drugs
A. Bactericidal.
B. Bacteriostatic.
III. Spectrum of Activity
A. Narrow.
B. Broad.
C. Extended.
IV. Adverse Effects
A. Bacterial resistance to the antibiotic.
B. Superinfections.
C. Gastrointestinal (nausea, vomiting, diarrhea).
D. Allergic reactions.
E. Photosensitivity.
F. Drug interactions.
V. Selection of the Appropriate Antibiotic
A. Treatment of acute odontogenic/orofacial infections.
B. Prophylaxis against infective endocardititis.
C. Prophylaxis for patients at risk for infection because of compromised host defense mechanisms resulting from disease; microbial tests.
1. Culture and sensitivity.
2. DNA probe.
VI. Systemic Antibiotics in Dentistry
A. Periodontal therapy.
1. Not for chronic periodontitis or plaque-induced gingivitis.
2. Aggressive periodontitis.
3. Necrotizing ulcerative gingivitis/peridontitis (NUG/NUP).
4. Periodontal surgery.
B. Endodontics.
C. Oral surgery.
D. Implants.
VII. Bactericidal Antibiotics
A. Penicillin.
1. First synthetic antibiotic.
2. Uses.
3. Actions.
a. Binding protein in bacterial cell wall.
b. Beta-lactamase.
4. Chemical modifications.
a. Penicillinase-resistant penicillins.
b. Broad-spectrum penicillins.
c. Extended spectrum penicillins.
5. Adverse effects/drug interactions.
B. Cephalosporins.
1. Action.
2. Four generations available.
3. Limited dental therapeutic usefulness.
4. Indications.
5. Side effects.
C. Metronidazole.
1. Action.
2. Dental indications.
3. Adverse effects (e.g., alcohol).
D. Fluoroquinolones.
1. Action.
2. Dental indications.
3. Adverse effects.
VIII. Bacteriostatic Antibiotics
A. Macrolides.
1. Erythromycin
a. Actions, bacteriostatic/bactericidal.
b. Limited dental indications.
2. Azalides (second generation)
a. Azithromycin, clarithromycin.
b. More dental indications.
c. Concentrates in PMNs (neutrophils, white blood cells).
d. Adverse effects.
e. Drug interactions.
B. Lincomycins.
1. Clindamycin.
2. Action.
3. Indications for periodontal therapy.
4. Adverse side effects.
5. Drugdisease interaction.
C. Tetracyclines.
1. Actions.
2. Indications in periodontal therapy; concentrates in gingival crevicular fluid (GCF).
3. Synthetic analogues.
4. Adverse effects.
5. Drug interactions.
6. Anticollagenase properties.
D. Miscellaneous antibacterials.
1. Sulfonamides.
a. Action.
b. Uses.
c. Decline in use.
d. Adverse effects.
2. Vancomycin
a. Action.
b. Uses.
c. Adverse effects.
IX. Prevention of Infective Endocardititis
A. Etiology; bacteremia.
B. Drug regimen (2007).
X. Topical Antibacterial Agents
A. Mouthrinse.
B. Irrigation.
C. First-generation agents; substantivity.
D. Second-generation agents.
XI. Controlled (Sustained)-Release Agents.
A. Subgingival.
B. Products.
1. Arestin.
2. Atridox.
3. PerioChip.
IX. Tuberculosis
A. Introduction.
1. Worldwide emergency (World Health Organization).
2. Bacterial infection caused by Mycobacterium tuberculosis.
3. Exposed (latent) versus active (highly contagious).
B. Testing for TB.
1. Screening.
a. Tuberculin skin test: skin reaction of PPD.
b. Newer blood test: Quanti-FERON-TB.
2. Infection.
a. Presence of organisms.
b. Normal chest X-ray.
c. No symptoms.
3. Disease.
C. Pharmacotherapy of TB
1. Goals: to cure the disease without relapse, prevent death, stop the spread of the disease, and prevent the emergence of drug-resistant TB.
2. Multidrug regimen (two or more drugs).
3. Long-term therapy.
4. First-line drugs.
a. Isoniazid (INH).
b. Rifampin.
c. Rifapentine.
d. Pyrazinamide.
e. Ethambutol.
5. Second-line drugs.
a. Cycloserine.
b. Ethionamide.
c. P-Aminosalicylic acid.
d. Streptomycin.
e. Capreomycin.
f. Ciprofloxacin.
D. Latent TB.
1. Prophylaxis recommended in people with + PPD.
2. Isoniazid (INH) 9 months—first-line therapy.
3. If resistance, use two drugs.
E. Active TB.
1. Postpone dental treatment.
2. Multidrug (four-drug) therapy.
3. Two phases of treatment.
a. Initial bactericidal phase.
b. Continuation phase.
F. Special situations.
1. TB + HIV.
a. Same as in patients without HIV except a higher dose of INH and rifampin in the continuation phase.
b. Higher risk for resistant TB.
2. Children: Start treatment immediately.
G. Many dental drug interactions (see Table 20–4).
XI. Hepatitis C
A. Pathogenesis.
1. Infection of the liver, can require liver transplant.
2. RNA virus.
3. Blood.
B. Treatment.
1. Interferons.
2. Herbal supplements (e.g., milk thistle).
XII. Hepatitis A and B
A. Hepatitis A.
1. Infectious hepatitis.
2. Oralfecal route.
3. HAV vaccine.
B. Hepatitis B.
1. Serum hepatitis.
2. Blood and body fluids.
3. Hepatitis B vaccine.
Teaching Tips
1. Impress upon the students the indiscriminate and overuse of antibiotics in dentistry and the development of bacterial resistance.
2. Explain the importance of learning which antibiotic will be effective in a given clinical situation.
3. Inform the students that antibiotics are not innocuous and there are many adverse effects including drugdrug, drugfood, and drugdisease interactions that clinicians should be cognizant about.
4. Impress upon the students indications when antibiotics should be used in dental cases.
5. Inform the students about tetracycline’s antibacterial and nonantibacterial properties.
6. Review current topics on antiretroviral agents (HAART). Have the class report on its findings.
7. Create a Jeopardy board for students to learn the various drugs used in the treatment of HIV infection.
8. Impress upon students the importance of knowing how to provide oral care to a patient with HIV/AIDS.
9. Impress upon the students how many immunocompromised patients develop oral conditions/lesions that are treated in the dental office.
10. Create flash cards for students to learn the adverse oral effects of antiretroviral agents.
Factoids
1. During World War II, research and production of penicillin moved from England to the United States to protect it from bombs .
2. The discoverer of penicillin was a poor farmer in Scotland. One day he rescued a boy from the bog. The father of the boy was deeply grateful for saving his son and provided the farmer’s boy with an education. The boy graduated from medical school in London and eventually went on to become known throughout the world as Sir Alexander Fleming, the discover of penicillin. Years later, the boy who was saved from the bog by Fleming’s father developed pneumonia. What saved his life this time? Penicillin. The name of the father? Lord Randolph Churchill. His son’s name: Sir Winston Churchill, a Prime Minister of Great Britain.
3. When the first potato came to Europe, people thought that it would cure TB and impotence in men.
4. In 1882, Robert Koch showed that tuberculosis was caused by a bacterium and that it was contagious.
Questions
1. Review the various antibiotics that are used in periodontics, endodontics, oral surgery, and implant dentistry.
2. Discuss the use of prophylactic antibiotics for a patient having periodontal surgery.
3. Discuss alternative antibiotics if the patient is allergic to penicillin and has an endodontic abscess.
4. Discuss the various adverse effects of common antibiotics used in dentistry.
5. Explain the differences between systemic antibiotics and controlled-release antimicrobial agents.
Classroom Activities
1. Assign each student or pair of students a broad-spectrum antibiotic to research on the Internet. Include classification, indications, contraindications, side effects, precautions, and drug interactions. Write on flash cards.
2. Give case studies (with clinical slides) involving odontogenic and soft tissue infections. Have students discuss what antibiotic may be appropriate. Discuss the dosage, instructions to the patient on how to take the antibiotic, and any adverse side effects and drug interactions.
3. Divide the students into groups. Have them use cards to write instructions on how dental patients should take antibiotics (patient drug education). For example, Should the antibiotics be taken on an empty stomach or without regard to meals? Can the patient take yogurt to prevent fungal infections? Can the patient take dairy products or antacids with the antibiotic? Allow time to discuss with the rest of the class.
4. Have students bring in examples of oral rinses and discuss the differences between them.
5. Bring in samples of controlled (sustained)-release devices such as Arestin and Atridox. Apply to typodonts. Discuss indications and adverse effects.
Multimedia Found in the PowerPoint Lecture Outline
Animations
1. Penicillin mechanism of action.
2. Ciprofloxacin mechanism of action.
3. Zidovidine mechanism of action.
4. Interferon mechanism of action.
5. Saquinavir mechanism of action.
Videos
1. Tuberculosis.
© 2013 by Education, Inc.
Weinberg, Instructor’s Resource Manual for Oral Pharmacology for the Dental Hygienist, 2nd Edition
