Drug Interaction Report

CONTRAINDICATED: Antituberculosis drugs may interfere with the anti-tumor activity of intravesical BCG, which contains a live, attenuated strain of Mycobacterium bovis. Available data suggest that intravesical BCG may be sensitive to most antibiotics, particularly those that are routinely used in the treatment of tuberculosis such as streptomycin, para-aminosalicylic acid (PAS), isoniazid (INH), rifampin, and ethambutol. It is reportedly not sensitive to pyrazinamide or cycloserine. Regardless of clinical susceptibility data, however, most antibacterials may still interfere with BCG in the bladder due to their high urinary recovery.

MANAGEMENT: Concomitant use of antituberculosis drugs is considered contraindicated during intravesical BCG therapy. Moreover, intravesical BCG should not be used in patients with active tuberculosis. If persistent fever develops or an acute febrile illness consistent with BCG infection occurs during intravesical BCG therapy, the medication should be permanently discontinued and the patient immediately evaluated and treated for BCG infection. An infectious disease consultation should be sought in determining the appropriate treatment. There are no data to suggest that the acute, local urinary tract toxicity common with intravesical administration of BCG is due to mycobacterial infection, thus antituberculosis drugs should not be used to prevent or treat the local, irritative toxicities of intravesical BCG.