Drug therapy chloramphenicol

Tetracyclines usually are the preferred agents for the treatment of rickettsial diseases. In patients allergic to these drugs, in those with reduced renal function, in pregnant women, and in children <8 years of age who require prolonged or repeated courses of therapy, chloramphenicol may be the drug of choice. Rickettsial diseases, such as Rocky Mountain spotted fever, respond well to chloramphenicol. For adults, a dose of 50 mg/kg/day is recommended for all the rickettsial diseases. The daily dose of chloramphenicol for children with these diseases is 75 mg/kg, divided into equal portions and given every 6-8 hours. Therapy should be continued until the patient has improved and is afebrile for 24—48 hours. 

If presumptive therapy is initiated, perform in vitro sensitivity tests concurrently, so that the drug may be discontinued if less potentially dangerous agents are indicated. Acute infections In acute infections caused by Salmonella typhi, chloramphenicol is a drug of choice. 

Monitoring Monitoring serum levels is important because of the variability of chloramphenicol s pharmacokinetics. Monitor serum concentrations weekly monitor more often in patients with hepatic dysfunction, in therapy more than 2 weeks, or with potentially interacting drugs. 

Many antimicrobial agents have similar pharmacokinetic properties when given orally or parenterally (ie, tetracyclines, trimethoprim-sulfamethoxazole, quinolones, chloramphenicol, metronidazole, clindamycin, rifampin, linezolid and fluconazole). In most cases, oral therapy with these drugs is equally effective, is less costly, and results in fewer complications than parenteral therapy. 

As for the treatment of plague, streptomycin and gentamicin are the drugs of choice. Doxycycline and chloramphenicol have also been used, but more treatment failures have been reported with these regimens. Ciprofloxacin is another alternative therapy. For the first-line regimens as well as ciprofloxacin, a 10-day course of intravenous antibiotics is recommended. For second-line therapies, 14 days are recommended. 

Visual impairment associated with chloramphenicol therapy usually recovers after the drug is discontinued, but pretreatment visual acuity is often not regained and visual field defects may persist. Some patients may tolerate further prolonged treatment with chloramphenicol without recurrent optic neuritis, and, occasionally, patients can demonstrate improvement of visual function despite continued therapy. 

Although bone marrow aplasia has not been related with certainty to either the daily or the total dose of chloramphenicol or to the sex or age of the patients, it has occurred almost exclusively in individuals who were taking prolonged therapy, particularly if they were exposed to the drug on more than one occasion (24). The condition is rare, occurring about once in every 18 000-50 000 subjects in various countries. These variations may in part depend on ethnic factors (25,26). For example, there have been very few cases reported in blacks (27). Bone marrow aplasia due to chloramphenicol has usually resulted in aplastic anemia with pancytopenia other forms, such as red cell hypoplasia, selective leukopenia, or thrombocytopenia, are less common. 

Concomitant use with anticoagulants may increase plasma levels of both drugs and, after continued therapy, may reduce the plasma levels of anticoagulant effects. Use with chloramphenicol, guanethidine, insulin, monoamine oxidase inhibitors, probenecid, salicylates, or sulfonamides may enhance the hypoglycemic effect by displacing tolazamide from its protein-binding sites. 

---