Erythromycin
Erythromycin is a macrolide antibiotic which has an antimicrobial spectrum similar or slightly wider to that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea.Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea, formerly known as Streptomyces erythraeus.
 Erythromycin A | |
| (3R*, 4S*, 5S*, 6R*, 7R*, 9R*, 11R*, 12R*, 13S*, 14R*)-4-((2,6-Dideoxy-3-C-methyl-3-O-methyl-a-L- ribo- hexopyranosyl) -oxy) -14- ethyl-7,12,13- trihydroxy - 3,5,7,9,11,13-hexa methyl-6- ((3,4,6-trideoxy-3-(dimethylamino)-b-D-xylo- hexopyranosyl)oxy)oxacyclotetradecane-2,10-dione | |
| Molecular Weight | 733.93 |
| Empiric Formula | C37H67NO13 |
| ATC code | J01FA01 |
| Metabolism | Liver |
| Pregnancy category | B (USA) A (Aus) |
| Table of contents |
|
2 Available forms 3 Mechanism of action 4 Pharmacokinetics 5 Metabolism 6 Side effects |
History
Abelardo Aguilar, a Filipino scientist sent some soil samples his employer Eli Lilly in 1949. Eli Lilly’s research team, led by J. M. McGuire, managed to isolate erythromycin, and it was subsequently launched in 1952 under the brand name Ilosone (after the Philippine region of Iloilo where it was originally collected from). Erythromycin was formerly also called ilotycin.
Available forms
Erythromycin is available in enteric-coated tablets, oral suspensions, ointments, gels and injections.
Mechanism of action
Erythromycin prevents bacteria from growing, by interfering with their protein synthesis. Erythromycin binds to the subunit 50S of the bacterial ribosome, and thus inhibits the translocation of peptides.
Pharmacokinetics
Erythromycin is easily inactivated by gastric acids, therefore all orally administered formulations are given as either enteric coated or as more stable salts or esters. Erythromycin is very rapidly absorbed, and diffused into most tissues and phagocytes. Due to the high concentration in phagocytes, erythromycin is actively transported to the site of infection, where during active phagocytosis, large concentrations of erythromycin are released.
Metabolism
Most of erythromycin is metabolised by demethylation in the liver. Its main route elimination route is in the bile, and a small portion in the urine. Erythromycin's half-life is 1.5 hours.
Side effects
Gastrointestinal intestinal disturbances such as diarrhoea, nausea, abdominal pain and vomiting are fairly common so it tends not to be prescribed as a first-line drug. More serious side-effects, such as reversible deafness are rare.