PRECAUTIONS: General Repeated courses of chloramphenicol treatment should be avoided if at all possible. Treatment should not be continued longer than required to produce a cure with little or no risk or relapse of the disease. Excessive blood levels may result from administration of the recommended dose to patients with impaired liver or kidney function. The dosage should be adjusted accordingly, or preferably, the blood concentration should be determined at appropriate intervals. The use of this antibiotic, as with other antibiotics, may result in an overgrowth of nonsusceptible organisms, including fungi. If infections caused by nonsusceptible organisms appear during therapy, appropriate measures should be taken. Laboratory Tests Baseline blood studies should be followed by periodic blood studies approximately every two days during therapy. The drug should be discontinued upon appearance of reticulocytopenia, leukopenia, thrombocytopenia, anemia or any other blood study findings attributable to chloramphenicol. However, it should be noted that such studies do not exclude the possible later appearance of the irreversible type of bone marrow depression. Drug Interactions Concurrent therapy with other drugs that may cause bone marrow depression should be avoided. Carcinogenesis, Mutagenesis, Impairment of Fertility No studies have been conducted in animals or humans to evaluate the possibility of these effects with chloramphenicol. Pregnancy Pregnancy Category C – Animal reproduction studies have not been conducted with chloramphenicol. There are no adequate and well-controlled studies to establish safety of this drug in pregnancy. It is not known whether chloramphenicol can cause fetal harm when administered to a pregnant woman. Orally administered chloramphenicol has been shown to cross the placental barrier. Because of potential toxic effects on the fetus (see ADVERSE REACTIONS, “Gray Syndrome” ), chloramphenicol should be given to a pregnant woman only if the potential benefit justifies the potential risk to the fetus. Nursing Mothers Chloramphenicol is excreted in human milk following oral administration of the drug. Because of the potential for serious adverse reactions in nursing infants from chloramphenicol, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother (see ADVERSE REACTIONS, “Gray Syndrome” ). Pediatric Use Precaution should be used in therapy of premature and full-term neonates and infants to avoid “gray syndrome” toxicity. Due to immature metabolic processes in the neonate and infant, excessive blood levels may result from administration of the recommended dose. The dosage should be adjusted accordingly or, preferable, the blood concentration should be determined at appropriate intervals (see ADVERSE REACTIONS , "Gray Syndrome" ). See DOSAGE AND ADMINISTRATION for dosing information in the pediatric population. Geriatric Use Clinical studies of chloramphenicol sodium succinate did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. Each gram (10 mL of a 10% solution) of chloramphenicol sodium succinate contains approximately 52 mg (2.25 mEq) of sodium.