Erythromycin History Available Forms Mechanism Of Action

Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea , formerly known as Streptomyces erythraeus.

1 History

2 Available forms

Erythromycin is available in enteric-coated tablets, oral suspensions, ointments, gels and injections.

3 Mechanism of action

Erythromycin prevents bacteria from growing, by interfering with their protein synthesis. Erythromycin binds to the subunit 50S of the bacterial ribosomeA ribosome is an organelle composed of rRNA (synthesized in the nucleolus) and ribosomal proteins. It translates mRNA into a polypeptide chain (e. a protein). It can be thought of as a factory that builds a protein from a set of genetic instructions., and thus inhibits the translocation of peptidePeptides are the family of molecules formed from the linking, in a defined order, of various amino acids. The link between one amino acid residue and the next is an amide bond, and is sometimes referred to as a peptide bond. An amide bond is somewhat shors.

4 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.

5 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.

6 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. Earlier case reports on sudden death prompted a study on a large cohort that confirmed a link between erythromycin, ventricular tachycardia and sudden cardiac death in patients also taking drugs that prolong the metabolism of erythromycin (like verapamil or diltiazem) by interfering with CYP3A4 (Ray et al 2004).

7 References

Ray WA, Murray KT, Meredith S, Narasimhulu SS, Hall K, Stein CM. Oral Erythromycin and the Risk of Sudden Death from Cardiac Causes. N Engl J Med 2004;351:1089-96.

Macrolide antibiotics

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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)

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