Chloramphenicol interaction with other drugs

So far only four cases of an interaction between rifampicin and chloramphenicol appear to have been reported. However, the evidence is of good quality and in line with the way rifampicin interacts with other drugs, so this interaction should be taken seriously. There is a risk that serum chloramphenicol levels will become subtherapeutic. The authors of the second report point out that raising the chloramphenicol dosage may possibly expose the patient to a greater risk of bone marrow aplasia. They suggest delaying rifampicin prophylaxis in patients with invasive Haemophilus influenzae infections until the end of chloramphenicol treatment. 

Chloramphenicol can interfere with the ehmination of drugs that are inactivated by hepatic metabolism, probably through a mechanism involving inhibition of microsomal enzymes. The mechanism has been claimed to be inactivation of microsomal enzymes via an intermediate reactive metabolite that binds covalently to the protein moiety of cjdochrome P450 (71). Assuming such a mechanism, chloramphenicol would be expected to interact with the metabolism of other drugs dealt with by cytochrome P450. 

Another point that has defied explanation is this SM is bacteriocidal only during periods of high rates of protein synthesis. Thus other protein inhibitors such as tetracyclines or chloramphenicol should interfere with its action, yet this theoretical drug interaction is not necessarily clinically contraindicated. In fact, a combination of streptomycin and tetracycline is the treatment of choice for glanders and brucellosis. 

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