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The spiramycin paradox

C R Smith1

  • 1Department of Epidemiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

The Journal of Antimicrobial Chemotherapy
|July 1, 1988
PubMed

Insights

Spiramycin demonstrates significant efficacy in infections, outperforming expectations based on its in-vitro activity. This enhanced effectiveness is attributed to superior tissue penetration and sustained concentrations, leading to improved patient outcomes.

Area of Science:

  • Pharmacology
  • Microbiology
  • Infectious Diseases

Background:

  • Spiramycin exhibits modest in-vitro antimicrobial activity.
  • Clinical and experimental data suggest spiramycin is effective in various infections.

Purpose of the Study:

  • To investigate the reasons behind spiramycin's in-vivo efficacy despite its in-vitro limitations.
  • To compare spiramycin's effectiveness with erythromycin in animal infection models.

Main Methods:

  • Analysis of spiramycin's pharmacokinetic profile, focusing on tissue and intracellular concentrations.
  • Evaluation of post-antibiotic effect (PAE) and subinhibitory effects.

Main Results:

  • Spiramycin achieves intracellular and tissue concentrations 10-fold higher than serum levels.
  • Lower clearance rates from tissues result in sustained drug concentrations.
  • Spiramycin exhibits a significant post-antibiotic effect, potentially enhancing in-vivo activity.

Conclusions:

  • Spiramycin's in-vivo effectiveness is significantly influenced by its pharmacokinetic properties, including high tissue penetration and sustained release.
  • These factors, along with post-antibiotic effects, explain its therapeutic success beyond in-vitro susceptibility data.

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