Chloramphenicol hypersensitivity reactions

Serious and sometimes fatal blood dyscrasias (patiiologic condition of blood disorder of cellular elements of blood) are die chief adverse reaction seen witii the adiniiiistration of chloramphenicol, hi addition to blood dyscrasias superinfection, hypersensitivity reactions, nausea, vomiting, and headache may be seen. It is recommended that patients receiving oral chloramphenicol be hospitalized so that patient observation and frequent blood studies can be performed during treatment witii this drug. 

Because of potential toxicity, bacterial resistance, and the availability of many other effective alternatives, chloramphenicol is rarely used. It may be considered for treatment of serious rickettsial infections such as typhus and Rocky Mountain spotted fever. It is an alternative to a B-lactam antibiotic for treatment of meningococcal meningitis occurring in patients who have major hypersensitivity reactions to penicillin or bacterial meningitis caused by penicillin-resistant strains of pneumococci. The dosage is 50-100 mg/kg/d in four divided doses. 

In a number of drug reactions, several of these hypersensitivity reactions may present simultaneously. Some adverse reactions to drugs may be mistakenly classified as allergic or immune when they are actually genetic deficiency states or are idiosyncratic and not mediated by immune mechanisms (eg, hemolysis due to primaquine in glucose-6-phosphate dehydrogenase deficiency, or aplastic anemia due to chloramphenicol). 

Hypersensitivity Reactions Rashes may result from chloramphenicol hypersensitivity. Fever may appear simultaneously or be the sole manifestation. Angioedema is a rare complication. Jaiisch-Herxheimer reactions may occur after institution of chloramphenicol therapy for syphUis, brucellosis, and typhoid fever. 

Certain antibiotics notably Penicillin, Streptomycin, Chloramphenicol and Novobiocin are strongly allergenic in sensitized individuals. The majority of the hypersensitivity reactions have occurred with Penicillin most probably because of its widespread usage. Sensitization occurs most often during therapeutic treatment. Once an individual is sensitized to Penicillin, for example, as little as 40 lU (0.024 mg) administered orally may elicit allergic reactions. While the only food-related epi-... 

Cahill KM (1962) Chloramphenicol hypersensitivity. A severe haemorrhagic reaction. Lancet 2 277-278... 

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