Interventions for Tuberculosis Control and Elimination 2002

Rifampicin may rarely cause pseudomembranous colitis 224,225 and
eosinophilc colitis. 226
Rifampicin has also been reported to induce lupus erythematosus. 227
Rifampicin has also been reported to cause myopathy. 228
With intermittent therapy, when higher doses than the now-recommended
daily dose equivalent have been used, a “flu” syndrome has frequently
been reported. 194,229 Also shortness of breath, hemolytic anemia,
and renal failure usually occur only if rifampicin is given intermittently. 194
Although not an adverse drug event, it should be noted that rifampicin
leads to orange discoloration of urine and tears, 230 and may permanently
damage soft contact lenses. 231 Intoxication leads to the “red man syndrome”.
232-234
Interactions. Rifampicin is an inducer of several enzymes in the
cytochrome P-450 system, 235 leading to numerous interactions with multiple
drugs. This action leads most frequently to faster elimination and lower
concentrations of the companion drug, an effect opposite to that seen with
the most common isoniazid interactions.
No important interactions between rifampicin and other anti-tuberculosis
drugs have been found, with the exception of para-aminosalicylic acid
preparations 139 containing a bentonite excipient. 175 Rifampicin reduces the
incidence of pyrazinamide-associated arthralgia, not by increasing pyrazinamide
elimination, but presumably through increased excretion of uric
acid. 236 Numerous interactions with other medications have been
described, 140,237-240 as detailed below.
Effect of rifampicin potentiated: Cotrimoxazole. 241 A pharmacokinetic study
reported an inhibitory effect of the anti-retroviral indinavir on the metabolism
of rifampicin. 242
Effect of rifampicin opposed: No drug has been identified yet that opposes
the action of rifampicin.
Effect of drug potentiated by rifampicin: Acetominophen hepatic failure and
encephalopathy as a result of suspected potentiation by rifampicin has been
reported. 105
Effect of drug opposed by rifampicin:
• anti-arrhythmics such as quinidine, 243, 244 phenytoin, 148 and lorcainide; 245
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