A simple formula for individualising ceftazidime dosage administered by continuous infusion in patients with haematological malignancies.

A formula is proposed for individualising ceftazidime dosage administered by continuous infusion in patients with haematological malignancies. Sixty patients were retrospectively randomised into Group A (n=30) to establish the formula and Group B (n=30) to evaluate this formula. Individual ceftazidime clearances were estimated from the ratio between the rate of infusion and plasma concentration at steady state. In Group A, ceftazidime clearance was significantly correlated with creatinine clearance. From this result, a formula (rate of infusion (g/day)=0.00133x[creatinine clearance (mL/min)]x[target concentration at steady state (mg/L)]) is proposed. This formula provided consistent estimations of ceftazidime plasma concentrations in Group B and should help clinicians to define the optimum ceftazidime dosage, particularly in patients with disturbed renal function.