Macrolide antibiotics, drug interactions and microsomal enzymes: implications for veterinary medicine.

The macrolide group of antibiotics includes natural members, pro-drugs and semi-synthetic derivatives, thus named because they are composed of a large aglycone ring (from 14 to 16 carbon atoms), to which are attached several sugars. Some of them are amino-sugars, containing a diethylamino, tertiary amine function. A number of antibiotics, including erythromycin, oleandomycin, triacetyl-oleandomycin (troleandomycin), carbomycin, spiramycin, tylosin, rosamicin, azithromycin, clarithromycin, dirithromycin and others, are members of this group. On a comparative basis, erythromycin and oleandomycin are similar, with the same basic 14-carbon lactone ring and side chain sugars. The remaining compounds contain a basic 15- or 16-carbon lactone ring and one or two side-chain sugars. Most of the macrolides are produced by Streptomyces spp bacteria. An exception is rosamicin, which is produced by Micromonospora. Clarithromycin and azithromycin are new semi-synthetic derivatives of erythromycin. Copyright 1999 W.B. Saunders Company Ltd.