The erythromycins (macrolide chemical structure) were significant in their development since they provided an extended spectrum of activity against not only gram positive organisms but gram negative as well. The macrolide antibiotics exert their antimicrobial action by binding to the bacterial 50S ribosomal subunit thereby inhibiting protein synthesis. Numerous erythromycin preparations exist today, including ethyl succinate, estolate and sterate preparations.
Until recent years, the erythromycins were relegated in use to relatively limited roles in the treatment of pediatric infections. The erythromycins were important in treating impetigo, bronchitis, and certain pneumonias (atypical and "walking"). However, their limited gram negative spectrum kept them from becoming legitimate choices for the treatment of acute otitis media. By combining sulfisoxazole with erythromycin, a combination was produced which offered an extended spectrum of activity for treatment of beta lactamase resistant infections, especially with otitis media and/or sinusitis.
Two new macrolides exist for the treatment of pediatric otitis media, sinusitis, and pharyngitis. Azithromycin and clarithromycin have an extended spectrum of coverage which includes the common pediatric respiratory pathogens along with chlamydia and mycoplasma. Both antibiotics are considered beta-lactamase resistant. As a group, these newer antibiotics may have similar drug interactions as erythromycin and are contraindicated in patients with a history of macrolide (erythromycin) sensitivity. Click here for more information on Azithromycin and Clarithromycin.