Carbapenems

At Carbapenems are antibiotics that belong to the group of beta-lactams. Carbapenems were originally called thienamycins. Due to their wide range of antimicrobial effects, they are used as medicinal substances. Some representatives are for example Ertapenem, Imipenem, Doripenem, Meropenem and Tebipenem. Carbapenems have the status of reserve antibiotics. Resistance to carbapenems is increasing within Europe.

What are carbapenems?

Basically, carbapenems are relatively well-tolerated antibiotics. Due to their spectrum of activity, they are divided into two groups. This is because they have a relatively large spectrum of activity in both the gram-negative and the gram-positive area. In addition, the beta-lactamase contained is characterized by high stability.

The first group of carbapenems includes, for example, imipenem or cilastatin, meropenem and doripenem. It should be noted that cilastatin alone has no antimicrobial effect. Ertapenem belongs to the second group. It differs from the other carbapenems in that it is only slightly effective against Acinetobacter and Pseudomonas. None of the carbapenems show any effect against methicillin-resistant staphylococci.

In principle, all carbapenems have a bactericidal effect. Since carbapenems are beta-lactam antibiotics, they are primarily used to treat certain bacterial infectious diseases that are based on sensitive pathogens. Their bactericidal effect extends to aerobic and anaerobic as well as gram-negative and gram-positive pathogens. In the majority of cases, the corresponding drugs are administered intravenously as an infusion.

Pharmacological effect

The effect of the carbapenems is due on the one hand to the special type of binding to penicillin-binding proteins. On the other hand, the active ingredient inhibits the cell wall synthesis of the bacteria.

The carbapenems are excreted via the kidneys. The carbapenem imipenem is, however, a substance that is highly damaging to the kidneys or nephrotoxic. To extend the half-life, the antibiotic is usually combined with cilastatin, which inhibits dehydropeptidase. This delays the hydrolytic breakdown of the drug in the kidneys. At the same time, nephrotoxicity is reduced.

Such a combination is not necessary for the other carbapenems. All carbapenems are partly metabolized and then eliminated renally. The half-life in people with healthy kidneys is around one hour.

Due to their relatively broad spectrum, carbapenems have an enormous effect on the intestinal flora. In addition, bacteria that are resistant to carbapenems can multiply rapidly during treatment and subsequently cause secondary infections.

In terms of their chemical structure, carbapenems differ from other beta-lactams. The characteristic five-membered ring of the respective beta-lactam has a carbon atom instead of a sulfur atom. First, the lead substance of the carbapenems was obtained from a type of fungus called Streptomyces cattleya. However, this lead substance, thienamycin, is not stable in the body. For this reason, carbapenems are now manufactured synthetically.

Medical application & use

In principle, all carbapenems are so-called reserve antibiotics. This means that they are only used in special and difficult to control infection conditions.Because if used uncritically, the formation of resistance is supported and side effects are increased.

Carbapenems are also used, for example, if there is already resistance to other beta-lactams. They are also used in the case of serious nosocomial infections as a result of unknown germs, especially if the originally planned therapy is not effective. In addition, carbapenems are also used for severe mixed infections, for example for peritonitis (inflammation of the peritoneum) with anaerobes and pus pathogens.

The spectrum of activity of the carbapenems includes almost all pathological gram-negative and gram-positive bacteria with the exception of mycoplasma and chlamydia. Carbapenems are also effective against Pseudomonas aeruginosa.

Carbapenems are only available through the parenteral route. The use of meropenem and imipenem or cilastatin is particularly helpful in the case of serious or even life-threatening infections of the kidneys, the urinary tract and the abdominal cavity. Serious infections of the joints and genital organs, soft tissue and skin also justify the use of the medication. In addition, serious infections of the respiratory tract as well as meningitis and sepsis are treated with the active ingredients.

The carbapenem ertapenem is mainly used for skin infections and pneumonia. Inflammation of the inner lining of the heart (endocarditis) can also be treated with carbapenems. The dosage of the active ingredients is based on the specialist information. In most cases, they are given intravenously, sometimes by injection.

Risks & side effects

Various side effects can occur when using carbapenems. The most common side effects include nausea, diarrhea and vomiting, rashes and other abnormalities at the infusion site. Headaches and inflammation of the vein also occur in some cases. Hypersensitivity reactions have been reported occasionally.

Carbapenems should not be used if hypersensitivity is already known. Treatment with carbapenems is contraindicated even if the patient is sensitive to other beta-lactam antibiotics. In addition, interactions can occur when carbapenems are taken at the same time as some other active substances.