title: Risperidone and 9-hydroxyrisperidone concentrations are not dependent on age or creatinine clearance among elderly subjects.
abstract: Risperidone is extensively metabolized to an active metabolite, 9-hydroxyrisperidone (9-OH), which is dependent on renal clearance. Risperidone and 9-OH clearances are reduced in the elderly when compared to young subjects. The objective of this study was to determine whether among elderly subjects, risperidone and 9-OH clearance would further decline with increasing age and decreasing creatinine clearance (CrCl). Twenty geriatric inpatients were evaluated in a naturalistic setting with regard to total daily risperidone dose and dosing interval. Creatinine clearance was determined using an 8-hour urine collection. Risperidone and 9-OH concentrations were determined by radioimmunoassay. Spearman's correlation coefficients were used to examine the impact of age and CrCl on concentrations of risperidone, 9-OH, their sum, and the quotient of 9-OH/risperidone. Mean age was 76.4 +/- 9 years (range 56-91). Mean CrCl was 55.4 +/- 32.8 mL/min/1.73 m2 (range 17-142 mL/min/1.73 m2). Mean risperidone daily dose was 1.3 +/- 0.7 mg. Steady-state risperidone and 9-OH concentrations were 4.1 +/- 5.3 ng/mL and 9.1 +/- 6.2 ng/mL, respectively. Mean 9-OH/risperidone was 6.2 +/- 6.1. Concentrations of risperidone, 9-OH, their sum, and 9-OH/risperidone were not significantly correlated with age or CrCl. These results were unchanged when concentrations were corrected for total daily risperidone dose. Among elderly subjects, risperidone and 9-OH clearance do not decline with increasing age or declining CrCl.
authors.affiliation: Pharmacy Department, Western Psychiatric Institute and Clinic, VA Pittsburgh Health System, Pennsylvania, USA.
authors.forename: Rae Ann
authors.initials: RA
authors.lastname: Maxwell
authors.forename: Robert A
authors.initials: RA
authors.lastname: Sweet
authors.forename: Benoit H
authors.initials: BH
authors.lastname: Mulsant
authors.forename: Jules
authors.initials: J
authors.lastname: Rosen
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Kirshner
authors.forename: Kari B
authors.initials: KB
authors.lastname: Kastango
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Pollock
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000652:urine*; D014150:Antipsychotic Agents / Q000652:urine*; D003404:Creatinine / Q000652:urine*; D005260:Female; D006801:Humans; D007555:Isoxazoles / Q000652:urine*; D008297:Male; D008875:Middle Aged; D000068882:Paliperidone Palmitate; D011743:Pyrimidines / Q000652:urine*; D011863:Radioimmunoassay; D018967:Risperidone / Q000652:urine*
chemical_list: D014150:Antipsychotic Agents; D007555:Isoxazoles; D011743:Pyrimidines; D003404:Creatinine; D018967:Risperidone; D000068882:Paliperidone Palmitate