| Indication |
For the treatment of the following mild-to-moderate infections caused by susceptible strains of microorganisms: acute bacterial exacerbations of chronic bronchitis, secondary bacterial infection of acute bronchitis, community-acquired pneumonia, pharyngitis/tonsilitis, and uncomplicated skin and skin structure infections. |
| Mechanism of action |
Dirithromycin prevents bacteria from growing, by interfering with their protein synthesis. Dirithromycin binds to the 50S subunit of the 70S bacterial ribosome, and thus inhibits the translocation of peptides. Dirithromycin has over 10 times higher affinity to the subunit 50S than erythromycin. In addition, dirithromycin binds simultaneously in to two domains of 23S RNA of the ribosomal subunit 50S, where older macrolides bind only in one. Dirithromycin can also inhibit the formation of ribosomal subunits 50S and 30S. |
| Absorption |
Oral dirithromycin is rapidly absorbed, with an absolute bioavailability of approximately 10%. Dietary fat has little or no effect on the bioavailability of dirithromycin. |
| Protein binding |
15 to 30% for erythromycylamine, the active compound. |
| Biotransformation |
Dirithromycin is converted by nonenzymatic hydrolysis during absorption to the active compound, erythromycylamine. Sixty to 90% of a dose is hydrolyzed to erythromycylamine within 35 minutes after dosing, and conversion is nearly complete after 1.5 hours. Erythromycylamine undergoes little or no hepatic biotransformation. No other metabolites of dirithromycin have been detected in the serum. |
| Route of elimination |
Not Available |
| Toxicity |
The toxic symptoms following an overdose of a macrolide antibiotic may include nausea, vomiting, epigastric distress, and diarrhea. |
| Affected organisms |
- Enteric bacteria and other eubacteria
|