Determination of the Postexposure Prophylactic Benefit of Oral Azithromycin and Clarithromycin Against Inhalation Anthrax in Cynomolgus Macaques
Abstract
BACKGROUND: Sufficient and diverse medical countermeasures against severe pathogenic infections, such as inhalation anthrax, are a critical need. Azithromycin and clarithromycin are antimicrobials commonly used for both upper and lower respiratory infections. They inhibit protein synthesis by blocking the formation of the 50S ribosomal subunit. To expand the armamentarium, these 2 antibiotics were evaluated in a postexposure prophylactic model of inhalation anthrax in cynomolgus macaques.
METHODS: This prophylaxis study had 4 test arms: azithromycin, clarithromycin, a levofloxacin control, and a placebo. Beginning 24 hours after exposure to a target challenge dose of 200 lethal dose 50 (LD50) of Bacillus anthracis Ames spores, animals were treated orally until 30 days postchallenge and then observed until 75 days postchallenge.
RESULTS: The test group that received clarithromycin had a survival rate of 67%. The test group that received azithromycin had a survival rate of 50%, but the peak azithromycin plasma levels achieved were <30 ng/mL-much lower than the expected 410 ng/mL. The levofloxacin positive control had a survival rate of 50%; all of the negative controls succumbed to infection.
CONCLUSIONS: The efficacy of clarithromycin prophylaxis was statistically significant compared with placebo, while azithromycin prophylaxis was indistinguishable from placebo. Given the low plasma concentrations of azithromycin achieved in the study, it is not surprising that half the…
Read the paper
Related studies
- Ferulic acid regulates the AKT/GSK-3β/CRMP-2 signaling pathway in a middle cerebral artery occlusion animal model
- Novel Pharmacokinetic/Pharmacodynamic Parameters Quantify the Exposure–Effect Relationship of Levofloxacin against Fluoroquinolone-Resistant Escherichia coli
- Photochemical behavior of levofloxacin
- Correlation Between Dissolution Profiles of Salt-Form Drugs in Biorelevant Bicarbonate Buffer and Oral Drug Absorption: Importance of Dose/ Fluid Volume Ratio
- Evaluation of the synergistic potential and mechanisms of action for de novo designed cationic antimicrobial peptides
- Synthesis of [11C]levofloxacin
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.