Medication Summary
The goals of pharmacotherapy are to eradicate the infection, to reduce morbidity, and to prevent complications.
Antibiotics
Class Summary
Treponemes are highly sensitive to azithromycin and penicillin, which remain the drugs of choice. Yaws, pinta, and endemic syphilis are treated with azithromycin or penicillin G benzathine. Alternatives are appropriate only if penicillin cannot be used. Tetracyclines or chloramphenicol have been used. Treatment failures with penicillin have been reported, but reinfection could not be ruled out.
Azithromycin (Zithromax, Zmax)
Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and blocks dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Nucleic acid synthesis is not affected.
Azithromycin concentrates in phagocytes and fibroblasts as demonstrated by in vitro incubation techniques. In vivo studies suggest that concentration in phagocytes may contribute to drug distribution to inflamed tissues. This drug is used to treat mild-to-moderate microbial infections.
Penicillin G benzathine (Bicillin-LA)
Interferes with synthesis of cell wall mucopeptides during active multiplication, which results in bactericidal activity. Combination of 1 M penicillin and 2 M ammonium base. Repository form providing tissue depot from which the drug is absorbed over days. Must be administered IM and provides detectable serum levels for 15-30 d.
Tetracycline
Treats gram-positive and gram-negative organisms as well as mycoplasmal, chlamydial, and rickettsial infections. Inhibits bacterial protein synthesis by binding with 30S and possibly 50S ribosomal subunit(s).
Doxycycline (Acticiate, Adoxa, Doryx, Monodox, Vibramycin)
Inhibits protein synthesis and thus bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria.
Chloramphenicol
Binds to 50S bacterial-ribosomal subunits and inhibits bacterial growth by inhibiting protein synthesis. Effective against gram-negative and gram-positive bacteria. Well-absorbed from GI tract and metabolized in the liver, where it is inactivated by conjugation with glucuronic acid and then excreted by the kidneys.
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Nigerian boy with ulcerative skin lesions characteristic of yaws. Courtesy of the CDC/Dr. Lyle Conrad.
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Photomicrograph (540X) of Treponema carateum obtained from an early pinta lesion. Courtesy of the CDC.
