Erythromycin and macrolides


Erythromycin belongs to the macrolide group of antibiotics. There are four commonly administered drugs in this group of substances. Erythromycin is also known under the trade names ErythrocinR and PaediatrocinR. It is an older standard antibiotic that has acid stability and can therefore be administered as a tablet. Depending on the diet, it is sometimes absorbed more quickly, sometimes more slowly. The drug has a very short half-life (2 hours), i.e. after 2 hours, half of the substance is no longer detectable.


Erythromycin acts by inhibiting the protein synthesis of the bacteria and thus kills the germs. The drug penetrates the tissue well and can take effect in the cells relatively quickly. In contrast, it is not cerebral water (liquor channel). This means that against bacterial diseases that affect the brain or the appendages of the brain (e.g. a Meningitis) Erythromycin is unlikely to be effective and should not be used. Unfortunately, erythromycin can be rapid Development of resistance bring about. This means that after treatment, some germs no longer react to the administration of erythromycin. In this case, the drug must be changed.

Areas of application

In the gram-negative range, erythromycin is effective against Neisseria, Bordetella pertussis, Legionella and Haemophilus influenzae. In the gram-positive range against Streptococcus pyogenes, Streptococcus pneumoniae and Streptococcus faecalis, Listeria, Actinomycetes and Clostridia. Furthermore, erythromycin works against mycoplasma, chlamydia and ureaplasma.

It is often used with an existing penicillin allergy in the patient, with acute respiratory infections that have arisen in the non-inpatient area (acquired on an outpatient basis), with ENT and lung infections, tonsillitis (tonsilitis), inflammation of the paranasal sinus (sinusitis), otitis media and Whooping cough used.

In the case of atypical pneumonia caused by the germs mycoplasma, chlamydia and legionella, it is also gladly given. Erythromycin is even the first drug of choice for Legionella infections of the lungs. The drug is also used for skin infections and diseases of the urinary system. Macrolides are used in pediatrics and in the treatment of pregnant patients and are one of the few antibiotics that these groups of patients like to use.

For external use, erythromycin is mainly found in eye ointments to relieve inflammation.

Learn more at: Eye ointment for a stye

Side effects

Erythromycin is well tolerated, but side effects can occur in some cases. The following should be mentioned here: complaints of the gastrointestinal tract, liver damage with an increase in the Liver values in the blood count, possibly a resulting one Jaundice (Yellowing of the skin and the eyes), Hearing impairments which, however, disappear again after stopping the drug. When administered via the venous blood system by infusion, care should be taken to ensure that erythromycin in liquid form results in venous irritation Phlebitis cause (phlebitis).

Please also read our article on this Antibiotic side effects


Macrolides block an enzyme in the liver that affects the breakdown of other drugs. This means that if drugs are administered in parallel, they are broken down more poorly and their concentration in the body increases. The prerequisite is that these drugs are broken down by the enzyme cytochrome P 450. The following drugs should be mentioned here: terfenadine, pentamidine, quinidine, lovastatin, simvastatin, atovarstatin, ciclospoprin A, tacrolism, digoxin, theophilline, triazolam, midazolam, dihydroergotamine, clozapine.

All drugs that treat cardiac arrhythmias (antiarrhythmics), neuroleptics (for seizures), drugs that cause increased potassium accumulation (loop diuretics, thiazides, laxatives) as well as combined antibiotics such as clindamycin and lincomycin, oral contraceptives (pill) and blood thinners should be used be given together with erythromycin only after careful consideration.


Erythromycin should not be given in patients with a history of liver disease or allergy.