Chloramphenicol is a potent antibiotic that has seen its use fall in recent years due to its ability to cause severe toxicity in humans and because of the development of resistance by some strains of bacteria. Nevertheless, it can be used to treat severe infections that do not respond well to other medications.
Uses
Chloramphenicol is a potent antibiotic that is effective against a wide array of bacteria, the Merck Manual explains. It is equally effective against gram-negative and gram- positive bacteria and also has activity against anaerobic bacteria, which are bacteria that do not need oxygen to live. Chloramphenicol, however, can cause some serious side effects and is generally only used for severe infections that have proven resistant to other antibiotics. Because some bacteria are resistant to chloramphenicol, the bacteria may need to be cultured and their susceptibility to the drug tested before chloramphenicol is used.
Mechanism
Chloramphenicol is a bacteriostatic drug, RsList explains. Bacteriostatic antibiotics work by slowing or preventing the growth of bacteria, which allows the immune system to fight the infection. Chloramphenicol targets bacterial ribosomes, which are structures in the bacteria necessary for the manufacture of new proteins. The ribosomes are the site where amino acids, which are the subunits of proteins, are assembled to form proteins. By preventing the amino acids from interacting with the ribosome, chloramphenicol halts protein synthesis.
Pharmacology
Chloramphenicol can be taken orally or injected into the body, RxMed notes. Oral chloramphenicol is taken in the form of chloramphenicol palmitate; in the gastrointestinal tract this compound is broken down and the free chloramphenicol is absorbed by the gastrointestinal tract. When chloramphenicol is injected, it is given in the form of chloramphenicol succinate, which is then broken down to yield chloramphenicol in the blood. Chloramphenicol is processed by the liver to form inactive breakdown products and is excreted via the urine.
In Neonates
Chloramphenicol must be given with care to newborns because it can cause a condition known as gray baby syndrome. Gray baby syndrome develops if unusually high levels of the drug build up in the blood, which can occur if the babyt's liver is unable to metabolize the drug properly. Gray baby syndome results in low body temperature, problems with breathing, and cyanosis, which is caused by low oxygen levels in the blood and turns the skin gray. Gray baby syndrome frequently leads to complete collapse of the circulatory system and is often fatal.
Side Effects
The most severe side effect of chloramphenicol, the Merck Manual explains, is suppression of the bone marrow. Because the bone marrow produces red and white blood cells as well as platelets, patients can develop anemia, clotting disorders and a weakened immune system. Most often this bone marrow suppression is temporary and will go away once therapy is stopped. However, in approximately one out of every 125,000 cases, irreversible idiosyncratic aplastic anemia will develop, which will result in permanent bone marrow depression. This condition can develop even after the initial course of therapy has been stopped.
