Antimicrobial Drugs for Oral Conditions

Viral Infections of the Oral Mucosa

  • Human Herpes Virus (HHV) infections:
    • Rx: Nucleoside analogue drugs (DNA polymerase inhibitors).
    • HHV 1 & 2: Herpes simplex virus.
    • HHV 3: Varicella/Zoster.
    • HHV4: Epstein Bar virus - Oral hairy leukoplakia.
    • HHV5: Cytomegalovirus.
    • HHV8: Kaposi sarcoma.
  • Other viral infections:
    • Human papilloma virus infections.
    • Mumps – Paramyxovirus (Rubulavirus).
    • Rubella (German measles) – Togavirus (Rubivirus).
    • Rubeola (Measles) – Paramyxovirus (Morbillivirus).

Herpes Simplex Virus 1 and 2

  • Primary infection: Primary herpetic gingivostomatitis.
    • Self-limiting.
    • Acyclovir suspension within 72 hours (Zovirax): 15mg/kg 5 times/day, 7 days (200mg).
    • Reduces duration of ulcers and viral shedding.
    • Support feeding, hydration, and pain relief.
    • Adults: Valacyclovir tablets, 1g twice daily, 7 days.
  • Secondary infection:
    • Topical treatment: Reduces pain and time to healing.
    • Herpes labialis: May spread across labial surface.
    • Topical antivirals:
      • 5% acyclovir cream (Acitop): Low bioavailability (apply 4 hourly).
      • Penciclovir: Fenivir (every 2 hours).
    • Sun protection.
    • Systemic treatment (prevention of lesions):
      • Acyclovir (200-400mg 5 times a day, 5 days), valacyclovir (500mg 12hourly), famcyclovir.
      • For >6 recurrences/year, severe pain, disfigurement, protracted disease.

Varicella/Zoster Virus

  • Primary: Varicella (Chickenpox)
    • Children: Acyclovir 80mg/kg/day divided in four doses for 5 days.
    • Adults: Acyclovir 4g/day divided into 5 doses.
    • Administer within 24 hours of rash onset to reduce lesion duration.
  • Secondary: Zoster (Shingles)
    • Administer antivirals within 72hrs of rash in elderly, immune deficient patients and those with facial shingles.
    • Acyclovir: 800mg, 5 times/day, 7days.
    • Valacyclovir: 1000mg, 3 times/day, 7days.
    • Famcyclovir: 250mg, 3 times/day, 7 days.
    • Zostavax vaccine for patients older than 60 years.

Herpangina and Hand-Foot-Mouth Disease

  • Coxsackievirus, echovirus, and other enteroviruses.
  • Treatment:
    • Symptomatic: Analgesics and antipyretics.
    • Anti-inflammatory (benzydamine).
    • Antimicrobial (CHX).

Human Papilloma Virus Infections

  • Multifocal epithelial hyperplasia, squamous papilloma, verruca vulgaris, condyloma acuminatum.
  • Rx: Primarily through surgery (scalpel, laser, electrosurgery).
  • Alternatives (off-label):
    • Podophylin resin.
    • Imiquimod.
    • Cidofovir.
    • Imiquimod: Topical immune modulator – causes release of cytokines.
    • Podophyllin: Mixture of resins, strong irritant, antimitotic.

Fungal Infections

  • Types: Candida, Aspergillosis, Mucormycosis, Histoplasmosis, Blastomycosis.

Candida Infection

  • Types: White (pseudomembranous, hyperplastic), Red (antibiotic sore mouth, associated with median rhomboid glossitis, denture-associated stomatitis, angular cheilitis).
  • Topical treatment:
    • Polyene: Nystatin (Canstat suspension or pessary).
    • Azoles:
      • Clotrimazole (Canesten cream or troche).
      • Miconazole (Daktarin oral gel).
  • Systemic treatment:
    • Triazoles: Fluconazole (Diflucan), Itraconazole (Sporanox), Posaconazole.
    • Imidazole: Ketoconazole.
  • Systemic Antifungal Agents:
    • Polyene: Amphotericin B (liposomal IV) for disseminated Candidiasis (S/E: nephrotoxic).
    • Triazole: Fluconazole (1st choice oropharyngeal Candida, 50-200mg/day 7-14 days), Itraconazole (200mg/day in solution when Fluconazole fails), Voriconazole (C krusei and C glabrata), Posaconazole.

Adjusting Treatment to Clinical Features (Candida)

  • Pseudomembranous Candida: Wipe away pseudomembranes, use topical antifungal.
  • Angular Cheilitis: Miconazole oral gel, Clotrimazole.
  • Hyperplastic Candida: Fluconazole for extended periods.
  • Denture-Associated Stomatitis: Miconazole/Clotrimazole oral gel applied to fitting surface of denture.

Histoplasmosis

  • Rx:
    • IV Amphotericin B.
    • Itraconazole (extended treatment: 200mg 2X/day for 5 months).

Mucormycosis

  • Zygomycetes (Absidia, Mucor, rhizopus).
  • Rx:
    • Control underlying disease.
    • Radical surgical debridement.
    • IV Amphotericin B.
    • Itraconazole, voriconazole, caspofungin.

Aspergillosis

*A. Flavus and A. fumigatus.

  • Itraconazole.

Bacterial Infections of the Oral Mucosa

  • Tuberculosis: rifampicin, isoniazid, pyrazinamide, ethambutol.
  • Syphilis: Benzathine penicillin 2.4M units IM.
  • Gonorrhoea: 250mg of intramuscular ceftriaxone AND 1g of oral azithromycin.
  • Actinomycosis: penicillin G IV, or ceftriaxone (3rd generation cephalosporin).

Necrotizing Periodontal Diseases

  • Necrotizing gingivitis (NG): Limited to gingiva, no loss of periodontal attachment.
  • Necrotizing periodontitis (NP): Loss of periodontal attachment.
  • Necrotizing mucositis (NM): Lesion extends beyond mucogingival junction.
  • NOMA/cancrum oris: Most severe, rapidly destructive.
  • Pathogens: Treponema spp, Selenomonas spp, Fusobacterium spp, Bacteroides melaninogenicus (Prevotella intermedia). Spirochetes and fusobacteria are most prevalent.
  • Treatment:
    • Scaling (as much as patient allows).
    • Chemical plaque control: Hydrogen peroxide 3% rinse, Chlorhexidine rinse 0.2% (twice daily, 30 seconds).
    • Systemic antibiotics (for systemic signs):
      • 1st choice: Metronidazole 200mg 3 times a day for 7 days.
      • 2nd choice: Amoxicillin 250mg 3 times a day for 7 days.

Periodontitis Treatment

  • Adjunct to cause-related therapy.
  • Intrasulcular: Tetracycline (doxy/minocycline) for anti-MMP effect.
  • Systemic: Amoxicillin, Metronidazole, Azithromycin, Clindamycin.

Bacterial Infections of the Tooth

  • Acute apical abscess or alveolar osteitis.
  • Pathogens: Staph and Strep.
  • Indications for antibiotics: Spreading of infection, systemic involvement.
  • Antibiotics: Amoxicillin (Clavulanic acid), Metronidazole, Clindamycin.

Chlorhexidine

  • Effective against G+/- bacteria and fungi.
  • Disrupts cell membrane, causing leakage of cytoplasm.
  • Bacteriostatic and bactericidal.
  • Substantivity (12 hours).
  • Significant post-antifungal effect.
  • Acts best on disrupted biofilm.
  • Maximum intra-oral concentration: 0.2%.
  • Combined with Benzydamine.