LEVOMYCETINUM (Laevomycetinum; synonym: chloramphenicol, Chloromycetinum) — antibiotic , for the first time received at biosynthesis by a producer — Streptomyces venezuelae. Industrial production is carried out by chemical synthesis. Total formula: With 11 H 12 Cl 2 N 2 O 5 . D-(—)трео-1-n-Нитрофенил-2-дихлорацетиламинопропандиол-1,3.
Crystal powder of bitter taste, low solubility in water, it is good — in alcohol and other organic solvents. Drug shall contain not less than 98,5% of the active beginning.
L. possesses a wide range of antimicrobic action, it is active concerning many gram-positive and gram-negative bacteria (tab.), rickettsiae, treponemas, the causative agent of trachoma, a psittacosis, inguinal lymphogranulomatosis. The mycobacterium does not affect acid resisting bacteria, in particular; clostridiums, pseudo-monads, pathogenic fungi are insensitive to it.
On the mechanism of action treats inhibitors of proteinaceous synthesis at a stage of transfer of amino acids on ribosomes; bakteriostatik, gets into cells. Resistance to L. develops slowly, stupeneobrazno.
At intake of L. quickly and fully it is soaked up, found in blood in 30 min. after introduction, the maximum of concentration is reached in 2 — 3 hours. In the greatest numbers of L. it is found in a liver, kidneys, gets through a blood-brain barrier; concentration in cerebrospinal liquid makes 30 — 50% of level in blood serum, at multi-day therapy remains 24 hours later after the termination of introduction. L. well gets into pleural, belly and synovial cavities where collects at the level of 30 — 50% of quantity of an antibiotic in blood serum. L. gets through a placenta, it is found in a vitreous, an iris. It is well soaked up at rectal use. To 90% of an antibiotic 10% — in not changed look are allocated with urine, from them, 3% are removed with bile, with a stake — 1 — 3%. Colibacilli hydrolyze L. in an organism, turning it into inactive decomposition products.
Use of levomycetinum in clinic
Levomycetinum is one of antibiotics of a broad spectrum of activity. It is applied to treatment inf. diseases of various etiology. In view of the high frequency of detection of resistant forms of activators to L., the expressed by-effects and implementation in medical practice of more effective and less toxic antibiotics of the indication to use of L. were sharply limited and its consumption decreases. The most serious side effect of L. its action on system of a hemopoiesis is (aplastic anemia with the progressing irreversible current, etc.). Rare, but heavy complication at use of L. — the cardiovascular collapse of newborns (heat - a syndrome) leading, as a rule, to deaths. Weight of the gematotoksichesky phenomena at reception of L. it can be not connected with a dose of drug. Nephrotoxic by-effects are observed seldom and are connected using high doses of L. Vozmozhna irritant action on went. - kish. path and anorectal syndrome.
Synthomycin — racemic substance of H.p. its dextrorotatory (D) isomer (dekstromitsetiny) which does not have antimicrobic activity is characterized by bigger toxicity and applied only locally in the form of linimentums.
L. appoint according to strict indications in the absence of effect of other antibiotics (e.g., at the typhoid, salmonellosises, meningitis and pneumonia caused by Haemophylus influenzae steady against ampicillin, etc.). It is not recommended to apply JT. at acute respiratory diseases, quinsy and others «small infections», in out-patient practice, and also with the preventive purpose. L. appoint inside in tablets and capsules in 30 min. prior to food in an average single dose for adult 0,5 g; the maximum daily dose — 3 g, the maximum course dose of 25 g. To children of L. appoint in the following doses: up to 3 years — on 10 — 15 mg on 1 kg of weight 3 — 4 times a day, from 3 to 8 years — 0,15 — 0,2 g on reception, are more senior than 8 years — 0,2 — 0,4 g on reception. In candles of L. release in a dose 0,1; 0,25 and 0,5 g; for topical administration in the form of 1% of ointment. Children can appoint stearate L. (eulevomitsetin), deprived of bitter taste. Sodium succinate L. — soluble drug for parenteral administration (intravenously, intramusculary), is produced in bottles on 0,5 and 1 g
the Table. Antibacterial range of levomycetinum
Bibliography: Navashin S. M. and Fomin I. P. Reference book on antibiotics, M., 1974.
S. M. Navashin.