Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1.   Pharmacodynamic properties
Pharmacotherapeutic group: Antibacterials for systemic use, ATC code: J01FA01

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.


Susceptibility testing breakpoints:
EUCAST clinical MIC breakpoints for erythromycin (Version 14.0, valid from 2024-01-01):
Pathogen                      Susceptible (mg/L)              Resistant (mg/L) Staphylococcus spp.                                   ≤1                              >1 Streptococcus groups A,B,C,G                        ≤ 0.25                          > 0.25 Streptococcus pneumoniae                            ≤ 0.25                          > 0.25 Viridans group streptococci                           IE*                            IE* Haemophilus influenzae                               Note1)                         Note1) Moraxella catarrhalis                               ≤ 0.25                          > 0.25 Listeria monocytogenes                                ≤1                              >1 Campylobacter jejuni                                  ≤4                             >4 Campylobacter coli                                    ≤8                             >8 Corynebacterium diphtheriae and
≤ 0.06                          >0.06
C. ulcerans
Kingella kingae                                      ≤ 0.5                           >0.5 Bacillus spp.
≤ 0.5                           >0.5 except B. anthracis


1) Clinical evidence for the efficacy of macrolides in H. influenza respiratory infections is conflicting due to high spontaneous cure rates. Should there be a need to test any macrolide against this species, the epidemiological cut-offs (ECOFFS) should be used to detect strains with acquired resistance. The ECOFF for erythromycin is 16 mg/l.
*"IE" indicates that there is insufficient evidence that the species in question is a good target for therapy with the drug. A MIC with a comment but without an accompanying S, I or R categorisation may be reported.
The prevalence of acquired resistance may vary geographically and with time for selected species and local information on resistance is desirable, particularly when treating severe infections. As necessary, expert advice should be sought when the local prevalence of resistance is known and the utility of the agent in at least some types of infections is questionable.

Pharmacokinetic Properties

5.2.   Pharmacokinetic properties

Following intravenous infusion, erythromycin is widely distributed throughout body tissues, including lung tissues.