BACKGROUND The pharmacokinetics of melphalan were studied in 20 patients with multiple myeloma, primary amyloidosis or lymphoma after IV dose of 140 mg/m2 infused over 30 minutes (two patients were treated with a higher dose). METHODS Six patients received melphalan alone, 8 received melphalan combined with total body irradiation, 2 received busulphan plus melphalan and 4 received the BEAM association (BCNU + etoposide + high dose aracytine + high dose melphalan). Creatinine clearance was measured immediately before the infusion of melphalan, and 9 blood samples were taken to monitor elimination kinetics. RESULTS Pharmacokinetic parameters (CIT, Vdss, t1/2) and areas under the curve (AUC) were comparable to those obtained by Ardiet et al after rapid IV injection. For all patients, AUC, CIT, Vdss, t1/2 beta and MRT were significantly correlated with creatinine clearance; the different pharmacokinetic parameters calculated showed great interindividual variations. CONCLUSIONS Renal insufficiency did not lead to a large decrease in melphalan clearance compared to interindividual variations in systemic clearance.