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Macrolide Antibiotics – Effect, Application & Risks

Macrolide antibiotics

The macrolide antibiotics are antibiotics that are bacteriostatic and have a macrolide. They inhibit the protein biosynthesis of the bacteria . The first and best-known macrolide antibiotic is erythromycin . Macrolide antibiotics are commonly used in children.

What are macrolide antibiotics?

Macrolide antibiotics (abbreviated: macrolides ) are bacteriostatic antibiotics . They represent their own “classification” within the various antibiotics. The common abbreviation macrolides is in the narrower sense the designation for a ring-shaped molecule occurring in all macrolide antibiotics, the macrolide. Macrolide antibiotics have a favorable spectrum of activity with few side effects and are therefore also well suited for use in children.

However, resistance to macrolide antibiotics is increasing. Many bacteria are already resistant to macrolide antibiotics, which is due to the fact that a modification of the ribosomal enzymes is sufficient for the acquisition of resistance. The acquisition of resistance is therefore relatively easy. Furthermore, there is a so-called cross-resistance between the various macrolide antibiotics. This means that as soon as a bacterium is resistant to one macrolide antibiotic, it is resistant to all macrolide antibiotics.

The “prototype” of macrolide antibiotics is erythromycin, which is derived from a species of fungus. In addition, there are the antibiotics josamycin and spiramycin , which are also obtained from fungal species . In an attempt to improve the spectrum of action and pharmacokinetic properties, the semi-synthetic derivatives roxithromycin , azithromycin and clarithromycin were developed.

Pharmacological action

Macrolide antibiotics are bacteriostatic. They inhibit the protein biosynthesis of the bacteria. It does this by attaching to the 50S subunit of the ribosome. In doing so, they block the enzyme translocase, which prevents further migration and growth of the polypeptide chain. This results in the bacteriostatic effect of macrolide antibiotics. They are particularly effective against metabolically active bacteria.

The macrolide antibiotics are generally lipophilic and are therefore well distributed in the tissues after absorption in the gastrointestinal tract . The excretion is predominantly biliary (via the bile ). The macrolides are broken down in the liver . They are metabolized by the CYP3A4 enzyme system during biotransformation.

Interference can therefore occur during the breakdown of drugs taken or applied at the same time. The breakdown of one of the drugs is delayed.

Medical Application & Use

Macrolide antibiotics are effective against gram-positive cocci and rods and gram-negative cocci. They are also effective against Legionella pneumophila, Bordetella pertussis , mycoplasma , spirochetes , chlamydia and Haemophilus influenzae .

The indications can be derived from the spectrum of activity of the macrolide antibiotics. However, it should be noted that the semi-synthetic macrolide antibiotics roxithromycin, clarithromycin and azithromycin have a broader spectrum of activity against gram-negative bacteria than erythromycin, josamycin and spiramycin.

Systemically, erythromycin is indicated for bronchitis , pneumonia , pertussis (whooping cough), otitis media (middle ear infection), sinusitis (inflammation of the paranasal sinuses), acne vulgaris, conjunctivitis (conjunctivitis) caused by chlamydia, diphtheria and urethritis caused by Chlamydia trachomatis or Ureaplasma urealyticum .

As an alternative to penicillins e.g. B. in penicillin allergy, erythromycin is also used to treat pharyngitis (pharyngitis), tonsillitis (tonsillitis), scarlet fever , erysipelas (erysipelas) and syphilis .

Azithromycin, a semi-synthetic derivative of the macrolide antibiotic group, can be used to treat infections of the upper respiratory tract , including inflammation of the sinuses (sinusitis), inflammation of the throat (pharyngitis), and inflammation of the tonsils (tonsilitis). Lower respiratory tract infections, including bronchitis and pneumonia, acute otitis media, skin and soft tissue infections, and uncomplicated genital infections caused by Chlamydia trachomatis or Neisseria gonorrhoeae (non-multiresistant strains) can also be treated with azithromycin.

A slightly expanded spectrum of activity of azithromycin compared to erythromycin can therefore be seen. Furthermore, azithromycin has a significantly longer half-life. For this reason, it can be used as a “three-day antibiotic”: only three tablets are administered 24 hours apart, but the effect lasts for 10 days due to the long half-life.

Risks & side effects

The potential side effects of macrolide antibiotics are harmless. For this reason and because of the broad spectrum of action, macrolide antibiotics are often used in children. The most frequently occurring side effects include complaints of the gastrointestinal tract, such as diarrhea , nausea and vomiting . Furthermore, hypersensitivity reactions are possible in the case of existing hypersensitivity ( allergy ) to macrolide antibiotics. Liver damage is one of the rare side effects.

However, it should be pointed out that the individual antibiotics from the group of macrolides can also have side effects that go beyond this. These can be found on the package insert and can be obtained from the doctor and pharmacist.

Furthermore, interactions (interactions) with other drugs are possible. There are also contraindications. However, these cannot be generalized for the group of macrolide antibiotics, since they are different for each of the macrolide antibiotics.

What all of these antibiotics have in common is that they must not be used in the case of hypersensitivity to a macrolide antibiotic.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.