Hastened activation to AIC w/ barbiturates, rifampicin, phenytoin. Potentiated activity of mercaptopurine, azathioprine, allopurinol. Altered incidence or severity of side effects w/ other antineoplastic agents. Increased leucopenic &/or thrombocytopenic effects w/ other medications causing these effects. Additive bone marrow depression w/ other bone marrow depressants or radiation therapy. Acute lung toxicity w/ fotemustine. Potentiated live virus vaccine replication, increased adverse effects of vaccine, decreased Ab response to vaccine.