Cisplatin administered as a continuous 5-day infusion: plasma platinum levels and urine platinum excretion.

Total and filterable platinum in plasma were monitored for seven courses (five patients, 25 mg/m2/day) using continuous 5-day infusions and one 30-minute infusion at a similar dose level (120 mg/m2). Maximum filterable (non-protein-bound) platinum levels (0.1-0.3 mg/L) for the extended infusions were ten to 40 times lower than that for the short-term infusion (4.0 mg/L). Filterable drug exposure as measured by the area under the [Pt]filterable-time curve is greater for the extended infusions (9.6 mg X hr/L) than that for the short-term infusion (4.8 mg X hr/L). Renal excretion of cisplatin (% of dose excreted/24-hour period after the beginning of the infusion) was measured for four courses of continuous 5-day infusions and for the 30-minute infusion. Urine excretion rates were lower for the continuous infusion (5%-8% of dose/24-hour period during the infusion) compared to the short-term infusion (33% of dose/24-hour period after the beginning of the 30-minute infusion).