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Clinical data
Trade names Dynabac
AHFS/Drugs.com Micromedex Detailed Consumer Information
MedlinePlus a604026
License data
  • B
Routes of
ATC code J01FA13 (WHO)
Pharmacokinetic data
Bioavailability 10%
Protein binding 15 to 30%
Metabolism Hyrolized to erythromycyclamine in 1.5 hours
CAS Number 62013-04-1 YesY
PubChem (CID) 6917067
DrugBank DB00954 YesY
ChemSpider 5292341 YesY
UNII 1801D76STL YesY
KEGG D03865 YesY
ChEBI CHEBI:474014 N
ECHA InfoCard 100.152.704
Chemical and physical data
Formula C42H78N2O14
Molar mass 835.074 g/mol
3D model (Jmol) Interactive image
 NYesY (what is this?)  (verify)

Dirithromycin is a macrolide glycopeptide antibiotic.

Dirithromycin (Dynabac) is a more lipid-soluble prodrug derivative of 9S-erythromycyclamine prepared by condensation of the latter with 2-(2-methoxyethoxy)acetaldehyde. The 9N, 11O-oxazine ring thus formed is a hemi-aminal that is unstable under both acidic and alkaline aqueous conditions and undergoes spontaneous hydrolysis to form erythromycyclamine. Erythromycyclamine is a semisynthetic derivative of erythromycin in which the 9-ketogroup of the erythronolide ring has been converted to an amino group. Erythromycyclamine retains the antibacterial properties of erythromycin oral administration. The prodrug, dirithromycin, is provided as enteric coated tablets to protect it from acid catalyzed hydrolysis in the stomach. Orally administered dirithromycin is absorbed rapidly into the plasma, largely from the small intestine. Spontaneous hydrolysis to erythromycyclamine occurs in the plasma. Oral bioavailability is estimated to be about 10%, but food does not affect absorption of the prodrug.


Dirithromycin is no longer available in the United States.[1] Since the production of dirithromycin is discontinued in the U.S, National Institutes of Health recommend that people taking dirithromycin should consult their physicians to discuss switching to another treatment.[2] However, dirithromycin is still available in many European countries.


  1. ^ "Dynabac Drug Details". U.S. Food and Drug Administration. Retrieved 2007-05-25. 
  2. ^ "Dirithromycin". MedlinePlus. U.S. National Library of Medicine. January 1, 2006. Archived from the original on 2007-03-29. Retrieved 2007-05-25.