The present study was undertaken to examine whether the pharmacokinetic profiles of pranoprofen, a non-steroidal anti-inflammatory drug, are altered in the elderly. Pranoprofen (75 mg) was given orally to six young and seven elderly subjects, and blood sample was obtained 0.5, 1, 2, 3, 5, 8 and 10 h after administration of the drug. The elimination half-life of pranoprofen was significantly longer and its plasma clearance was significantly lower in the elderly than those levels in the young subjects. The area under the plasma concentration-time curve in the elderly group was significantly greater than that in the younger group. No significant difference was observed in the maximum plasma concentration or the time to maximum plasma concentration between the two groups. These data indicate that the pharmacokinetic profiles of pranoprofen are altered in the elderly.