Decreased hepatic drug demethylation in patients receiving chemo-immunotherapy.

The effect of immunotherapy and chemotherapy on hepatic N-demethylation of aminopyrine was studied by means of the aminopyrine breath test (ABT) in 32 patients with cancer. The aminopyrine breath test (ABT) was decreased in 3 of 11 patients (27.3%) receiving intradermal BCG (+/- DTIC) at a dose of 3 X 10(7) viable organisms. One of 4 (25%) patients receiving intradermal BCG (+/- DTIC) at 3 X 10(8) viable organisms per dose developed an altered ABT. Changes were not seen in patients receiving aerosol BCG (2 patients), and intravenous C. parvum (2 patients), subcutaneous C. parvum (3 patients), and intravenous Cyclophosphamide (2 patients). Six of 7 patients (85.7%) receiving both intravenous C. parvum and Cyclophosphamide had a decreased ABT. These data indicate that chemo-immunotherapy depressed hepatic aminopyrine N-demethylation and suggests that patients treated with chemoimmunotherapy should be carefully observed for possible alterations of hepatic drug metabolism.