Interaction Of Rifampicin Research Articles

Interaction aspects of antimycobacterial drugs in the chemotherapy of tuberculosis. II. The role of rifampicin and other drugs in the dependent or independent action of drug associations in vitro.

The concentration related interaction of rifampicin, in associations with isoniazid, ethambutol, streptomycin and <i>p</i>-aminosalicylic acid on <i>M. tuberculosis</i> (H₃₇Rv) <i>in vitro</i> has been statistically evaluated. The independency or dependency of drugs has been assessed either on the basis of their concentrations or their proportions in associations studied. The effect of drug-resistant mutants has been excluded. The data indicate that rifampicin and ethambutol act dependently in a wide range of concentrations and proportions, both drugs participate equally on the increased effectivity of a given association. In associations of rifampicin with other drugs the dependent (increased) interaction is limited to some concentrations, particularly of rifampicin.

Replication of bacteriophage M 13: inhibition of single-strand DNA synthesis by rifampicin.

Synthesis of single-stranded DNA of bacteriophage M 13 is blocked by rifampicin. This inhibition is not observed in an Escherichia coli mutant possessing an RNA polymerase resistant to rifampicin. Since rifampicin stops single-strand synthesis faster than chloramphenicol, inhibition by rifampicin does not seem to result from a transcriptional block of protein synthesis, particularly in view of the long half-life of the messenger RNA for M 13. It is, therefore, concluded that the interaction of rifampicin with RNA polymerase directly affects single-strand DNA synthesis. Possible mechanisms are discussed.