Chloramphenicol, adverse drug reaction

Holt D., D. Harvey, and R. Hurley (1993). Chloramphenicol toxicity. Adverse Drug Reactions and Toxicological Reviews 12 83-95. 

In some drug reactions, several of these hypersensitivity responses 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 caused by chloramphenicol). 

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. 

Educating the Patient and Family Anytime a drug is prescribed for a patient, the nurse is responsible to ensure that the patient has a thorough understanding of the drug, the treatment regimen, and the potential adverse reactions. Not all of the miscellaneous anti-infectives are prescribed for use within the clinical setting. Chloramphenicol, metronidazole, and... 

Blood dyscrasias, mostly dose independent, are among the most important allergic-type adverse reactions to drugs. Aplastic anemia is a serious but rare (presumably) idiosyncratic reaction. It has been reported in association with chloramphenicol, quinacrine, phenylbutazone, mephenytoin, gold compounds, and potassium chlorate. Hemolytic anemia, thrombocytopenia, and agranulocytosis may result from an unusual, acquired sensitivity to a variety of widely used drugs including aminopyrine, phenylbutazone, phenothiazines, propylthiouracil, diphenylhydantoin, penicillins, chloramphenicol, sulfisoxazole, and tolbutamide. 

The severity of an adverse reaction is usually much more important than its frequency. For an effective anti-infective drug (e.g. an aminopenicillin preparation), high frequency of an exanthema (in 5%-10% of patients or 5-10,000 of 100,000 treatments) is acceptable however, for a life-threatening reaction such as pancytopenia (in the case of chloramphenicol) observed in only about 2 of 100,000 patients treated (very low frequency), other drugs are preferred except in rare and selected indications. 

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