cloranfenicol (or " cloramfenicol") is Antibiotic was obtained for the first time from a bacterium of the ground of the family of actinomicetales, Streptomyces venezuelae, later would be elaborated from other species of Streptomyces and at present it takes place by synthesis.

Antecedents

Cloranfenicol effective Drug against an ample phantom of microorganisms, especially Estafilococos, but due to its serious indirect effect (damage to the bony marrow, including aplásica anemia) in humans, its use is limited very serious infections, like typhoid Fever . In spite of its indirect effect, the WHO pleads for its use in many countries of the Third World in the absence of cheaper treatments. In Mexico was used in the decades of ochentas and noventas to deal with diarrheas unwarranted way, without control and irresponsibly.

Description

Cloranfenicol is a white and crystalline, neutral substance with a very bitter flavor. In order to eliminate the flavor characteristic I am created a palmitic technique of esterificación with acid to produce palmitato of cloranfenicol that is a substance without flavor without losing the therapeutic effectiveness. Cloranfenicol is stable in neutral and acid solutions, but when arriving at 10 PHS the drug is inactivated. He is moderately soluble in water, more soluble in Alcohol and ether . The 37 solutions to °C are deteriorated gradually with an average life of 6 months. A version of the antibiotic exists that instead of being palmitato is succinato sodium of cloranfenicol. He is resistant to temperatures of sterilization which is very common in microbiological laboratories.

Pharmacology

As much the palmitato as the succinato of cloranfenicol must be hidrolizados to cloranfenicol in the organism before it can exert its anti-bacterial action. The antibiotic inhibits the protein synthesis blocking the activity of peptidil Enzyme transferasa when being united to the subunit 50S of Ribosoma avoiding the formation of the peptide connection.

Pharmacokinetics

Absorption

After the oral administration, cloranfenicol in the form of palmitato or sodium succinato, is absorbed well from the gastrointestinal tract. The salts of palmitato and sodium succinato are hidrolizan quickly to cloranfenicol frees and the serum concentrations rise approximately to their maximum point in 3 hours.

Distribution

Cloranfenicol most of distributes in weaves and liquids of the body, including Liquid cefalorraquídeo, Liver and kidneys . Near 60% of the drug one to plasmatic proteins.

Metabolism

The metaboliza compound of origin mainly by the hepatic glucuronil trasferasa in inactive Metabolites .

Excretion

Near the 10 - 12% of the dose are excreted by the kidneys like drug without change. The rest is eliminated in the form of metabolites without pharmacological activity.

Precautions and warnings

Cloranfenicol must be avoided by people with smaller infections or Hypersensitivity to the drug. It does not have to be used in patients with renal or hepatic insufficiency. As special cases tell to the people with acute Porfiria and with deficiency of Glucose-6-phosphate deshidrogenasa (DG6F). The drug can be excreted active through maternal milk.

Medicinal interactions

Cloranfenicol inhibits the metabolism of Fenitoína, Dicumarol, Ciclofosfamida and Fenobarbital what produces that these drugs prolong their average life and its potential toxicity is increased.

Adverse reactions

The depression of bony Marrow is the more serious and dangerous adverse effect of cloranfenicol. Two types of depression of the bony marrow exist: one that does not depend on the administered dose nor on the time of use. can lead to aplásica Anemia and is irreversible. The other type of medullary depression if it depends on the dose and relates to plasmatic concentrations of the 25 drug that exceed mg/mL. The difference with the type of mentioned depression previously is that this one can spontaneously revert when suspending the medication.
  • Haematic: aplásica Anemia, hypoplastic anemia, Granulocytopenia and Trombocitopenia .

  • Central Nervous system: Migraine, Depression weighs, confusion, delirium, peripheral Neuropathy .
  • Gastrointestinal: Nauseas, vomits, diarrhea, estomatitis.
  • Skin: Comezón, angioneurótico Edema

Resistance

The resistance to cloranfenicol must Gene cat . This gene codifies a called enzyme " cloranfenicol acetiltransferasa" that it deactivates cloranfenicol connecting one or two groups Acetyl derived from the acetil-S-coenzyme To, to the groups hidroxilo of cloranfenicol. This acetylation prevents the union of cloranfenicol to ribosoma bacterial.

Pharmaceutical presentations

  • Capsules of 250 mgs and 500 mgs

  • Suspension : Containing 150 mgs by each 5 ml
  • Solution (pharmaceutical) : that it contains cloranfenicol to the 0,5%
  • ophthalmic Ointment : with cloranfenicol in concentrations of 1%.
  • Solution ótica: Presentation for instilación in the ear with 0,5% of drug.
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