The pharmacokinetic properties of meropenem were investigated in nine critically ill patients treated by continuous venovenous hemofiltration (CVVH). All patients received one dose of 1 g of meropenem intravenously. High-flux polysulfone membranes were used as dialyzers. Meropenem levels were measured in plasma and ultrafiltrate by high-performance liquid chromatography. The total body clearance and elimination half-life were 143.7 +/- 18.6 ml/min and 2.46 +/- 0.41 h, respectively. The post- to prehemofiltration ratio of meropenem was 0.24 +/- 0.06. Peak plasma drug concentrations measured 60 min postinfusion were 28.1 +/- 2.7 microgram/ml, and trough levels after 6 h of CVVH were 6.6 +/- 1.5 microgram/ml. The calculated total daily meropenem requirement in these patients with acute renal failure and undergoing CVVH was 2,482 +/- 321 mg. Based on these data, we conclude that patients with severe infections who are undergoing CVVH can be treated effectively with 1 g of meropenem every 8 h.