A pharmacokinetic study of piroxicam in children.

Feldene Melt (piroxicam) is commonly used for analgesia following day case surgery. The manufacturer's recommended paediatric dose is 0.4 mg.kg(-1) once daily. In children, plasma piroxicam levels of 3-5 microg.ml(-1) are associated with effective analgesia. However, in adults a single dose of 20 mg piroxicam (0.4 mg.kg(-1) for a 50-kg adult) produces plasma levels of only 1.5-2.2 microg.ml(-1). We therefore studied plasma levels achieved by 0.4 mg.kg(-1) or 1.0 mg.kg(-1) piroxicam in 22 children aged between 3 and 16 years, undergoing elective orthopaedic surgery, in order to investigate the adequacy of single dosing. The first 12 patients received 0.4 mg.kg(-1) Feldene Melt pre-operatively. Following assay of plasma piroxicam levels, a further 10 patients received 1.0 mg.kg(-1) Feldene Melt. In both groups, five blood samples were taken at 2-hourly intervals. The mean (95% CI) piroxicam level following 0.4 mg.kg(-1) was 2.90 (2.33-3.54) microg.ml(-1), compared to 5.87 (4.58-7.16) microg.ml(-1) following 1.0 mg.kg(-1) (p = 0.0003).