| Item |
Information |
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Drug Groups
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approved |
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Description
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An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106) |
| Indication |
Used in treatment of cholera, as it destroys the vibrios and decreases the diarrhea. It is effective against tetracycline-resistant vibrios. It is also used in eye drops or ointment to treat bacterial conjunctivitis. |
| Pharmacology |
Chloramphenicol is a broad-spectrum antibiotic that was derived from the bacterium Streptomyces venezuelae and is now produced synthetically. Chloramphenicol is effective against a wide variety of microorganisms, but due to serious side-effects (e.g., damage to the bone marrow, including aplastic anemia) in humans, it is usually reserved for the treatment of serious and life-threatening infections (e.g., typhoid fever). Chloramphenicol is bacteriostatic but may be bactericidal in high concentrations or when used against highly susceptible organisms. Chloramphenicol stops bacterial growth by binding to the bacterial ribosome (blocking peptidyl transferase) and inhibiting protein synthesis. |
| Toxicity |
Oral, mouse: LD50 = 1500 mg/kg; Oral, rat: LD50 = 2500 mg/kg. Toxic reactions including fatalities have occurred in the premature and newborn; the signs and symptoms associated with these reactions have been referred to as the gray syndrome. Symptoms include (in order of appearance) abdominal distension with or without emesis, progressive pallid cyanosis, vasomotor collapse frequently accompanied by irregular respiration, and death within a few hours of onset of these symptoms. |
| Affected Organisms |
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Enteric bacteria and other eubacteria |
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| Biotransformation |
Hepatic, with 90% conjugated to inactive glucuronide. |
| Absorption |
Rapidly and completely absorbed from gastrointestinal tract following oral administration (bioavailability 80%). Well absorbed following intramuscular administration (bioavailability 70%). Intraocular and some systemic absorption also occurs after topical application to the eye. |
| Half Life |
Half-life in adults with normal hepatic and renal function is 1.5 - 3.5 hours. In patients with impaired renal function half-life is 3 - 4 hours. In patients with severely impaired hepatic function half-life is 4.6 - 11.6 hours. Half-life in children 1 month to 16 years old is 3 - 6.5 hours, while half-life in infants 1 to 2 days old is 24 hours or longer and is highly variable, especially in low birth-weight infants. |
| Protein Binding |
Plasma protein binding is 50-60% in adults and 32% is premature neonates. |
| References |
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Bhutta ZA, Niazi SK, Suria A: Chloramphenicol clearance in typhoid fever: implications for therapy. Indian J Pediatr. 1992 Mar-Apr;59(2):213-9.
[Pubmed]
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Wali SS, Macfarlane JT, Weir WR, Cleland PG, Ball PA, Hassan-King M, Whittle HC, Greenwood BM: Single injection treatment of meningococcal meningitis. 2. Long-acting chloramphenicol. Trans R Soc Trop Med Hyg. 1979;73(6):698-702.
[Pubmed]
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Puddicombe JB, Wali SS, Greenwood BM: A field trial of a single intramuscular injection of long-acting chloramphenicol in the treatment of meningococcal meningitis. Trans R Soc Trop Med Hyg. 1984;78(3):399-403.
[Pubmed]
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Pecoul B, Varaine F, Keita M, Soga G, Djibo A, Soula G, Abdou A, Etienne J, Rey M: Long-acting chloramphenicol versus intravenous ampicillin for treatment of bacterial meningitis. Lancet. 1991 Oct 5;338(8771):862-6.
[Pubmed]
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Nathan N, Borel T, Djibo A, Evans D, Djibo S, Corty JF, Guillerm M, Alberti KP, Pinoges L, Guerin PJ, Legros D: Ceftriaxone as effective as long-acting chloramphenicol in short-course treatment of meningococcal meningitis during epidemics: a randomised non-inferiority study. Lancet. 2005 Jul 23-29;366(9482):308-13.
[Pubmed]
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