Actinomycosis Medication

Updated: Jul 24, 2018
  • Author: Jason F Okulicz, MD, FACP, FIDSA; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication

Medication Summary

High-dose penicillin administered over a prolonged period (6 months to 1 year) is the cornerstone of therapy for actinomycosis. These recommendations were developed at a time when patients with actinomycosis typically presented late in the course of illness with large lesions, often receiving intermittent antibiotic therapy. In addition, modern imaging modalities were not available to monitor therapy. Success with shorter courses of therapy (< 6 mo) has been reported, especially in cervicofacial actinomycosis. [8] Ultimately, the treatment duration should be tailored to the individual patient based on clinical and radiographic response. Patients should be monitored more closely if shorter treatment durations are considered.

The risk of actinomycetes developing penicillin resistance appears to be minimal. Lack of a clinical response to penicillin usually indicates the presence of resistant companion bacteria, which may require modification of the antibiotic regimen (ie, addition of an agent that is active against these copathogens).

Antibiotics that possess no activity against Actinomyces species include metronidazole, aminoglycosides, aztreonam, co-trimoxazole (TMP-SMX), penicillinase-resistant penicillins (eg, methicillin, nafcillin, oxacillin, cloxacillin), and cephalexin. The data concerning the fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) are limited; however, treatment success has been cited in case reports. [9, 10]

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Antibiotics

Class Summary

Therapy must cover all likely pathogens in the context of this clinical setting.

Penicillin G (Pfizerpen, Bicillin)

DOC for treatment of actinomycosis. Interferes with synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.

Penicillin VK (Pen-Vee K, V-Cillin-K)

DOC for treatment of actinomycosis. Interferes with synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.

Doxycycline (Bio-Tab, Doryx, Vibramycin)

For nonpregnant patients with penicillin allergy. Inhibits protein synthesis and, thus, bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria.

Clindamycin (Cleocin)

Alternative in patients allergic to penicillin. Lincosamide agent that inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Drawback is lack of coverage against some companion bacteria.

Amoxicillin/clavulanic acid (Augmentin)

Drug combination that can be used alone in mild to moderately severe cases of actinomycosis; covers both pathogenic actinomycetes and companion bacteria, which frequently are resistant to penicillin.

Ceftriaxone (Rocephin)

Covers both pathogenic actinomycetes and companion bacteria, which frequently are resistant to penicillin. Useful in moderately severe to severe forms of cervicofacial and thoracic actinomycosis. Third-generation cephalosporin with broad-spectrum, gram-negative activity; lower efficacy against gram-positive organisms. Arrests bacterial growth by binding to penicillin-binding proteins.

Imipenem/cilastatin (Primaxin)

Covers both pathogenic actinomycetes and companion bacteria, which frequently are resistant to penicillin. Useful in moderately severe to severe forms of abdominal and pelvic actinomycosis.

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