Retorin Suspension Mechanism of Action

Pharmacotherapeutic group: Macrolides, Lincosamides and Streptogramins, Macrolides.
Pharmacology: Pharmacodynamics: Mechanism of Action: Erythromycin exerts its antimicrobial action by binding to the 50S ribosomal sub-unit of susceptible microorganisms and suppresses protein synthesis.
Erythromycin is usually active against most strains of the following organisms both in vitro and in clinical infections.
Gram positive bacteria - Listeria monocytogenes, Corynebacterium diphtheriae (as an adjunct to antitoxin), Staphylococci spp, Streptococci spp (including Enterococci).
Gram negative bacteria - Haemophilus influenzae, Neisseria meningitidis, Neisseria gonorrhoeae, Legionella pneumophila, Moraxella (Branhamella) catarrhalis, Bordetella pertussis, Campylobacter spp.
Mycoplasma - Mycoplasma pneumoniae, Ureaplasma urealyticum.
Other organisms - Treponema pallidum, Chlamydia spp, Clostridia spp, L-forms, the agents causing trachoma and lymphogranuloma venereum.
Note: The majority of strains of Haemophilus influenzae are susceptible to the concentrations reached after ordinary doses.
Pharmacokinetics: Absorption is facilitated if the stomach is empty.
Peak blood levels normally occur within 1 hour of dosing of erythromycin ethyl succinate granules. The elimination half-life is approximately 2 hours. Doses may be administered 2, 3 or 4 times a day.
Erythromycin ethyl succinate is less susceptible than erythromycin to the adverse effect of gastric acid. It is absorbed from the small intestine. It is widely distributed throughout body tissues. Little metabolism occurs and only about 5% is excreted in the urine. It is excreted principally by the liver.
The drug is not removed by either peritoneal dialysis or haemodialysis. It diffuses readily into intracellular fluids and antibacterial activity can be achieved at essentially all sites.
There is some retention in liver and spleen. Only low concentrations are achieved in cerebrospinal fluid, unless the meninges are inflamed. Diffusion into the aqueous humour, but not the vitreous humour of the eye is good. A significant proportion is bound to serum proteins.