Reduced absorption of oral ciprofloxacin after chemotherapy for haematological malignancy.

Six patients with newly diagnosed haematological malignancy were treated with ciprofloxacin 500 mg orally, as chemoprophylaxis during neutropenia. The mean serum ciprofloxacin concentrations, measured 1, 2, 3 and 4 h after dosage were reduced for up to ten days after the start of chemotherapy. The mean maximum serum concentration and AUC 0-4 h were reduced from 3.7 (95% confidence limits, 2.3-5.1) mg/l and 10.7 (6.2-15.2) mg/l.h pre-chemotherapy to 2.0 (1.4-2.6) mg/l and 5.7 (4.4-7.0) mg/l.h, 13 days after chemotherapy. Absorption of ciprofloxacin is reduced after cytotoxic chemotherapy, and this may have implications for the use of oral ciprofloxacin in this group of patients.