Patients with hepatic or renal dysfunction are often treated with 5-fluorouracil (5-FU), but there are few data to confirm the safety of this practice.

Patients with solid tumors were eligible if they were able to fit into one of three organ dysfunction cohorts: I, creatinine >1.5 but < or =3.0 mg/dl and normal bilirubin; II, bilirubin >1.5 but <5.0 mg/dl with normal creatinine; or III, bilirubin > or =5.0 mg/dl with normal creatinine. 5-FU doses were escalated separately within each of the three cohorts. Leucovorin (LV) dosage was fixed at 500 mg/m(2). 5-FU was given as a 24-h infusion at 1000, 1800 or 2600 mg/m(2), and plasma concentrations were measured every 3 h during the first two infusions for each patient.

Sixty-four patients were treated. Toxicities did not appear to be related to organ dysfunction cohort. A weekly dose of of 5-FU 2600 mg/m(2) produced dose-limiting toxicity (DLT) in six of 20 evaluable patients. These DLTs included grade 3 fatigue (n = 3), grade 2 neutropenia precluding weekly dosing (n = 1), grade 3 thrombocytopenia (n = 1) and grade 3 mental status changes (n = 1). There was no relationship between serum bilirubin or serum creatinine and 5-FU clearance.

Patients with elevated bilirubin may be safely started on a weekly regimen of 5-FU 2600 mg/m(2) with leucovorin 500 mg/m(2) as a 24-h continuous infusion.