Drug Interaction Report

MONITOR: Chloramphenicol may inhibit the bactericidal effect of penicillins. Chloramphenicol acts by inhibiting cellular protein synthesis and can change actively growing bacteria into static ones. Since penicillins work by inhibiting cell wall synthesis, their effectiveness may be reduced. In addition, neurologic toxicity may be enhanced. Data have been conflicting, and no antagonism or synergistic effects have been reported.

MANAGEMENT: Until more information is available, this combination should probably be reserved for conditions where it has been found to be efficacious and avoided in situations where bactericidal activity is necessary, such as in bacterial meningitis or staphylococcal endocarditis. If the combination is necessary, some experts recommend administering the penicillin several hours before the chloramphenicol. Patients should be closely monitored for altered antimicrobial efficacy.