Which medications in the drug class Macrolides are used in the treatment of Bacterial Pneumonia?

Updated: Sep 30, 2020
  • Author: Justina Gamache, MD; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Answer

Macrolides

Azithromycin (Zithromax)

In otherwise uncomplicated pneumonia, azithromycin is the initial drug of choice, as it covers most of the potential etiologic agents, including Mycoplasma species. Compared with other drugs, this agent also causes less GI upset, and it has the potential for good compliance because of its reduced dosing frequency. Azithromycin has better action against H influenzae compared with erythromycin, but its main disadvantage is cost.

Azithromycin is a macrolide that acts by binding to 50S ribosomal subunit of susceptible microorganisms and blocks dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Nucleic acid synthesis is not affected. This agent concentrates in phagocytes and fibroblasts as demonstrated by in vitro incubation techniques. In vivo studies suggest that the concentration in phagocytes may contribute to drug distribution to inflamed tissues.

Clarithromycin (Biaxin)

Clarithromycin is another initial drug of choice that is used in otherwise uncomplicated pneumonia. It is used to treat CAP caused by H influenzae, M pneumoniae, S pneumoniae, M catarrhalis, H parainfluenzae, or C pneumoniae (TWAR strain). Clarithromycin appears to cause more GI symptoms (eg, gastric upset, metallic taste) than azithromycin.

This agent is a semisynthetic macrolide antibiotic that reversibly binds to the P site of the 50S ribosomal subunit of susceptible organisms and may inhibit RNA-dependent protein synthesis by stimulating dissociation of peptidyl t-RNA from ribosomes, causing bacterial growth inhibition.

Erythromycin (E.E.S., E-Mycin, Eryc, Ery-Tab, Erythrocin)

Erythromycin covers most potential etiologic agents, including Mycoplasma species. The oral regimen may be insufficient to adequately treat Legionella species, and this agent is less active against H influenzae. Although the standard course of treatment is 10 days, treatment until the patient has been afebrile for 3-5 days seems a more rational approach. Erythromycin therapy may result in GI upset, causing some clinicians to prescribe an alternative macrolide or change to a tid dosing.

Erythromycin is a macrolide that inhibits bacterial growth possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest.


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