COMPARISON OF THE PHARMACOKINETICS OF NAPROXEN TABLETS AND SUSPENSIONIN CHILDREN

Twenty-three children, aged 8 to 14 years, with postoperative pain, we re randomly assigned to receive a fixed 250-mg dose (4.66-7.58 mg/kg) of naproxen as either a liquid suspension or tablet. After an overnigh t fast, the serum concentrations were measured before and at 0.5, 1, 2 , 3, 4, 8, 12, 18, and 24 hours after administration of naproxen. The concentration versus lime data were best fit to a one-compartment open model. The area under the concentration versus time curve, apparent v olume of distribution (VDss/F), and elimination parameters (CL/F, Ke, elimination half-life) were similar in children who received suspensio n or tablets. Although the apparent maximum peak plasma concentration (Cmax) was greater in children who received tablets compared with thos e who received the suspension, Cmax/area under the curve (AUC), appare nt time to maximum peak concentration (tmax), Ka, and estimated time t o 10%, 50%, and 90% absorption (T10, T50, T90) were not different. The dose range was relatively narrow; hence, direct relationships between dose and elimination parameters, VDss/F, apparent tmax, Ka, T10, T50 or T90 were not observed. Neither VDss/F or CL/F were age related over the relatively narrow range of ages that were studied. Elimination of naproxen naproxen in our patients was more rapid than has previously been reported in children or adults, however. From a practical standpo int, naproxen tablets and suspension seem to be bioequivalent in fasti ng children ages 8 to 14 pears.