Average plasma concentrations of ertapenem following a single 30 minute intravenous infusion of a 20 mg/ kg (up to a maximum dose of 1 g) dose in patients 13 to 17 years of age were 170.4 micrograms/ ml (Cmax) at 0.5 hour postdose (end of infusion), 7.0 micrograms/ ml at 12 hour postdose, and 1.1 microgram/ ml at 24 hour postdose.