Erythromycin is produced by a strain of Saccharopolyspora erythraea (formerly Streptomyces erythraeus ) and belongs to the macrolide group of antibiotics. It is basic and readily forms salts with acids. The base, the stearate salt, and the esters are poorly soluble in water. Erythromycin ethylsuccinate is an ester of erythromycin suitable for oral administration.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of E.E.S. and other antibacterial drugs, E.E.S. should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
E.E.S. is indicated in the treatment of infections caused by susceptible strains of the designated organisms in the diseases listed below
Upper respiratory tract infections of mild to moderate degree caused by Streptococcus pyogenes, Streptococcus pneumoniae, or Haemophilus influenzae (when used concomitantly with adequate doses of sulfonamides, since many strains of H. influenzae are not susceptible to the erythromycin concentrations ordinarily achieved). (See appropriate sulfonamide labeling for prescribing information.)
Lower-respiratory tract infections of mild to moderate severity caused by Streptococcus pneumoniae or Streptococcus pyogenes.
Listeriosis caused by Listeria monocytogenes.
Pertussis (whooping cough) caused by Bordetella pertussis. Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals rendering them noninfectious. Some clinical studies suggest that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals.
Respiratory tract infections due to Mycoplasma pneumoniae.
Skin and skin structure infections of mild to moderate severity caused by Streptococcus pyogenes or Staphylococcus aureus (resistant staphylococci may emerge during treatment).
Diphtheria: Infections due to Corynebacterium diphtheriae, as an adjunct to antitoxin, to prevent establishment of carriers and to eradicate the organism in carriers.
Erythrasma: In the treatment of infections due to Corynebacterium minutissimum.
Intestinal amebiasis caused by Entamoeba histolytica (oral erythromycins only). Extraenteric amebiasis requires treatment with other agents.
Acute pelvic inflammatory disease caused by Neisseria gonorrhoeae: As an alternative drug in treatment of acute pelvic inflammatory disease caused by N. gonorrhoeae in female patients with a history of sensitivity to penicillin. Patients should have a serologic test for syphilis before receiving erythromycin as treatment of gonorrhea and a follow-up serologic test for syphilis after 3 months.
Syphilis caused by Treponema pallidum: Erythromycin is an alternate choice of treatment for primary syphilis in patients allergic to the penicillins. In treatment of primary syphilis, spinal fluid examinations should be done before treatment and as part of follow-up after therapy.
Erythromycins are indicated for the treatment of the following infections caused by Chlamydia trachomatis: conjunctivitis of the newborn, pneumonia of infancy, and urogenital infections during pregnancy. When tetracyclines are contraindicated or not tolerated, erythromycin is indicated for the treatment of uncomplicated urethral, endocervical, or rectal infections in adults due to Chlamydia trachomatis.
When tetracyclines are contraindicated or not tolerated, erythromycin is indicated for the treatment of nongonococcal urethritis caused by Ureaplasma urealyticum.
Legionnaires' Disease caused by Legionella pneumophila. Although no controlled clinical efficacy studies have been conducted, in vitro and limited preliminary clinical data suggest that erythromycin may be effective in treating Legionnaires' Disease.
Prevention of Initial Attacks of Rheumatic Fever
Penicillin is considered by the American Heart Association to be the drug of choice in the prevention of initial attacks of rheumatic fever (treatment of Streptococcus pyogenes infections of the upper respiratory tract, e.g., tonsillitis or pharyngitis). Erythromycin is indicated for the treatment of penicillin-allergic patients.3 The therapeutic dose should be administered for 10 days.
Prevention of Recurrent Attacks of Rheumatic Fever
Penicillin or sulfonamides are considered by the American Heart Association to be the drugs of choice in the prevention of recurrent attacks of rheumatic fever. In patients who are allergic to penicillin and sulfonamides, oral erythromycin is recommended by the American Heart Association in the long-term prophylaxis of streptococcal pharyngitis (for the prevention of recurrent attacks of rheumatic fever).3