Imipenem

At Imipenem it is an antibiotic. The active ingredient belongs to the group of carbapenems.

What is imipenem?

Imipenem is an antibiotic drug that belongs to the subclass of carbapenems. Carbapenems are considered broad spectrum antibiotics because they are effective against many different types of bacteria. They are part of beta-lactams and usually serve as reserve antibiotics. These remedies are usually only used when the usual antibiotic preparations fail. They are also used more and more frequently to combat severe hospital infections.

Imipenem is produced semi-synthetically from thienamycin. This natural substance is produced by the bacterium Streptomyces cattleya. Imipenem has been approved in Europe since the mid-1980s. The drug is always administered together with cilastatin.

Pharmacological effect

Imipenem is able to kill bacteria. The antibiotic develops this effect by inhibiting the build-up of bacterial cell walls. Imipenem can bind to proteins in both gram-negative and gram-positive bacteria, which are responsible for docking with penicillin. Penicillin is similar in chemical structure to imipenem.

A distinctive feature of Imipenem is that it is combined with cilastatin. Cilastatin is an enzyme inhibitor. Inside the kidneys, it blocks the enzyme dehydropeptidase-I (DHP-I). This participates in the breakdown of imipenem from the body. This will increase the duration of the antibiotic's action.

However, some types of bacteria are insensitive to imipenem. Possible causes for this are the weakened attachment of the antibiotic to penicillin proteins, a weak permeability of the outer membrane of gram-negative bacterial species, an active removal of imipenem from the cells of the bacteria and the presence of rare enzymes that make up the structure of the antibiotic is under attack.

If the bacteria are resistant to other carbapenems such as doripenem, ertapenem and meropenem, there is usually also a resistance to imipenem.

The excretion of imipenem from the body takes place for the most part via the kidneys. Around 70 percent of the material is released unchanged. The liver metabolizes the remaining 30 percent. Around one percent of the antibiotic is also excreted in the stool.

Medical application & use

The combination of imipenem and cilastatin is given to children and adults against complicated urinary tract infections, severe pneumonia, which can also be acquired in hospital, complicated infections in the abdomen or peritoneum, and severe infections of the tendons, muscles and skin to treat.

Imipenem is also suitable for treating infections that occur during or after birth. A drug against blood poisoning (sepsis) can also be useful. In contrast, the use of carbapenem in case of meningitis (meningitis) is not considered effective.

Imipenem's range of uses covers gram-negative, gram-positive and aerobic bacteria. In contrast, there are gaps in effectiveness with mycoplasma, Legionella, MRSA, Enterococcus faecium, Clostridium difficile and Stenotrophomonas maltophilia. Imipenem has only a moderate effect against Pseudomonas.

Neither imipenem nor cilastatin can be absorbed through the digestive tract. For this reason, it is always administered as an intravenous infusion, which is prepared by healthcare professionals. The usual dose for adults and adolescents is 500 milligrams of imipenem and cilastatin every six to eight hours. If the patient has kidney disease, the dose can be reduced.

Risks & side effects

Various side effects are conceivable through the use of imipenem and cilastatin. These primarily include nausea, vomiting, diarrhea, elevated liver values, blockage or inflammation of the blood vessels and an excess of immature blood cells.

Occasionally, low blood pressure, deficiency of white blood cells, deficiency of all blood cells, muscle spasms, seizures, drowsiness, fever and an increase in blood counts may also occur. Even mental disorders such as confusion or delusions are possible. Penetrating the infusion may cause redness and pain at the injection site.

There are also some known contraindications to taking Imipenem. This includes hypersensitivity to imipenem, cilastatin, or other carbapenems. Careful consideration by the doctor of imipenem administration is required if the patient is suffering from brain injuries or epileptic seizures. These promote seizures or confusion. The same applies to liver disease, as it could get worse.

A study in pregnant patients taking imipenem has not been conducted. However, animal experiments showed damage to the offspring. Therefore, imipenem is only used during pregnancy if the benefit to the mother is greater than the risk to her child. Imipenem is not considered suitable for children under one year of age.

Interactions between imipenem and other drugs can also occur. For example, patients who took the antiviral drug ganciclovir at the same time suffered some brain cramps. In epileptics there is a risk that taking it together with valproic acid can lead to epileptic fits. For this reason, doctors are always looking for an alternative to the antibiotic.