SII-ONCO-BCG is sensitive to most antibiotics specially to anti-tubercular drugs like Streptomycin, Isoniazid, Ethambutol, Rifampicin and PAS (Para-amino Salicylic Acid). It is not known whether interactions occur during intravesical instillation of SII-ONCOBCG or whether the interactions result in clinically relevant reduction of multiplication activity of SII-ONCO-BCG. Hence, it is not clear whether activity of SII-ONCO-BCG is influenced by concomitant therapy with antibiotics. If a patient is receiving antibiotics treatment then intravesical instillation should be postponed till completion of antibiotics treatment (also see the "Contraindications"). Studies on interaction with other drugs are not performed.