ERYTHROMYCIN (Erythrocin): What is used for?

What is Erythromycin?

Erythromycin (Eritromicina) is a drug used for the treatment of certain infections. The product ingredients are: Erythromycin estolate, Erythromycin ethylsuccinate, Erythromycin gluceptate, Erythromycin lactobionate, Erythromycin phosphate, Erythromycin stearate, Sulfate and Thiocyanate.

The brand names of Erythromycin in the United States are: Erythrocin, EryPed, Ery-Tab, E-Mycin.

Erythromycin Mechanism of Action (MOA)

Interferes with bacterial protein synthesis at ribosomal 50S subunit level.

Therapeutic Indications, uses and benefits of Erythromycin

  • S. pyogenes infection: respiratory, skin and soft tissue, alternative in strep throat.
  • S. alphahemolytic infection, viridans: prophylaxis of bacterial endocarditis before dental intervention, upper airway surgery, in patients with acquired valvular disease or congenital heart disease.
  • Staphylococcus aureus infection: acute, mild or moderate skin and soft tissue.
  • S. pneumoniae: otitis media, pharyngitis, pneumonia, mild-moderate.
  • By M. pneumoniae: respiratory.
  • By U. urealyticum: urethritis in male ads.
  • For C. jejuni: enterocolitis, severe or prolonged diarrhoea.
  • By H. influenzae: upper respiratory, with sulfonamide.
  • By C. trachomatis: conjunctivitis of the newborn, pneumonia in infancy, urogenital infection in pregnancy, urethral, endocervical and rectal when tetracyclines are contraindicated.
  • T. pallidum: syphilis 1 aria in people allergic to penicillin.
  • By C. diphtheriae: antitoxin adjuvant, to prevent carriers.
  • By E. histolytica: intestinal amebiasis.
  • L. monocytogenes.
  • By N. gonorrhoeae: women with a history of sensitivity to penicillin, alternative to penicillin in PID.
  • By B. pertussis: elimination of nasopharynx, prophylaxis in exposed.
  • May be effective in legionnaire’s disease.

Dosage of Erythromycin

Oral, IV:

Adults: 1 or 2 g/day in 3-4 doses, can be increased up to 4 g/day.
Prevention of hemolytic alpha streptococcal endocarditis, viridans: 1 g before surgery and 500 mg/6 h, in 8 doses.
Primary syphilis: 30-40 g fractionated for 10-15 days.
Amoebic dysentery: 250 mg/6 h, 10-14 days. Legionnaire’s disease: 1-4 g/day, fractionated, 14-21 days.

Children: 30-50 mg/kg/day in 3-4 doses. Amoebic dysentery: 30-50 mg/kg/day fractionated, 14-21 days.
Streptococcal infection with a history of rheumatic heart disease: min. 10 days.


Hypersensitivity to macrolides, history of jaundice.

Warnings and precautions with Erythromycin

Monitor liver function for risk of dysfunction; pregnancy and lactation.

Liver failure

Caution. Monitor liver function.

Interactions with Erythromycin

  • Plasma concentration increased by: terfenadine.
  • Avoid associating with: ergot alkaloids.
  • Increased effect of: triazolam.
  • Monitor with: lovastatin.
  • Increases level of: theophylline and derivatives, bromocriptine.
  • Antagonism with: lincomycin, clindamycin.
  • Caution with: cyclosporine, digoxin, carbamazepine, hexobarbital, phenytoin, antacids, penicillins.
  • Prothrombin time extension with: warfarin and oral anticoagulants.


Crosses the placental barrier, although there is no evidence of action in the fetus, consider possible risks.


This active ingredient passes into breast milk. Although there is no conclusive evidence of an action on the infant, consider the possible risks of its administration.

Adverse reactions and side effects of Erythromycin

Abdominal pain, nausea, vomiting, diarrhoea, anorexia, overgrowth of non-susceptible microorganisms, hives, skin rash, anaphylactic phenomena, reversible hearing loss.


Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).

In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.


UNII: 63937KV33D
PubChem CID: 12560
NCI Thesaurus: C476

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