title: The pharmacokinetics of piroxicam in elderly persons with and without renal impairment.
abstract: 1. Piroxicam pharmacokinetics were assessed in three groups of subjects: (1) young healthy volunteers, (2) healthy elderly subjects (mean +/- s.d. creatinine clearance 88 +/- 13 ml min-1), and (3) elderly patients with renal insufficiency (creatinine clearance 60 +/- 10 ml min-1) following the administration of piroxicam 20 mg as a single dose and after chronic dosing of 20 mg once daily for 4 weeks. 2. Piroxicam and 5'-hydroxypiroxicam concentrations were measured by h.p.l.c. in serum and urine samples collected for 96 h after the single dose and for 144 h after chronic dosing. Unbound concentrations of piroxicam were determined by ultrafiltration. 3. Elimination half-lives, steady state concentrations of piroxicam and 5'-hydroxypiroxicam, clearances of total and unbound piroxicam, volumes of distribution normalized for body weight, and urinary recovery of 5'-hydroxypiroxicam were not influenced by age or renal function. Volumes of distribution after the single dose were significantly lower in women compared with men (mean +/- s.d. 10.0 +/- 2.9 l vs 12.9 +/- 5.0 l; 95% confidence interval of the difference 0.1 to 5.6). 4. Percent unbound piroxicam values were 1.46 +/- 0.3% after the single dose and 1.45 +/- 0.2% at steady state. There were significant reductions in clearance and clearance of unbound piroxicam between single and chronic doses. The half-lives of 5'-hydroxypiroxicam (80.9 +/- 44 h) were significantly longer than those of piroxicam (54.9 +/- 26 h) after chronic dosing.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Wishard Memorial Hospital, Indianapolis 46202.
authors.forename: A C
authors.initials: AC
authors.lastname: Rudy
authors.forename: N L
authors.initials: NL
authors.lastname: Figueroa
authors.forename: S D
authors.initials: SD
authors.lastname: Hall
authors.forename: D C
authors.initials: DC
authors.lastname: Brater
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003404:Creatinine / Q000652:urine; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D010894:Piroxicam / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D011485:Protein Binding; D051437:Renal Insufficiency / Q000097:blood / Q000378:metabolism*
chemical_list: D010894:Piroxicam; C051024:5'-hydroxypiroxicam; D003404:Creatinine