ABSTRACT
Tiaprofenic acid is a non-steroidal anti-inflammatory drug which is highly protein bound and excreted mainly by the kidneys. Previous pharmacokinetic studies with tiaprofenic acid in conventional formulations in elderly arthritic patients have shown no evidence of accumulation of this drug over periods of up to 12 weeks. A sustained release formulation of the drug was given to 14 elderly arthritic patients over 4 weeks and plasma profiles obtained at the beginning and end of treatment over a 24 h period. Area under the curve (AUC), maximum plasma concentration (Cmax) and plasma concentration at 24 h (C24) were calculated and elimination half life (t1/2) was estimated. AUCs to infinity at week 0 were compared with AUCs to infinity at week 4 as a measure of drug accumulation. No significant differences were found for any of these parameters between the beginning and end of treatment. The mean t1/2 for both weeks was approximately 4.4 h. There was no evidence of any accumulation.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/metabolism , Arthritis/metabolism , Propionates/metabolism , Aged , Aged, 80 and over , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Arthritis/drug therapy , Delayed-Action Preparations , Female , Half-Life , Humans , Kinetics , Male , Propionates/administration & dosage , Propionates/therapeutic useABSTRACT
We have studied the single dose and steady-state pharmacokinetic of tiaprofenic acid in ten elderly arthritic patients living in the community (5 men and 5 women) taking 200 mg tid for 8 days. The mean area under the plasma concentration-time curves to 8 h (AUC (0-8)) did not alter significantly from day 1 to day 8 (77.25 to 79.61 micrograms X ml-1 X h). The mean terminal phase half-life (t1/2) was 2.05 h and 2.25 h on Days 1 and 8 respectively in patients in whom the calculations were possible (7 patients on Day 1 and 6 patients on Day 8). The median observed time of maximum concentration (tmax) and the mean observed maximum plasma concentration (Cmax) of 100 min and 21.3 micrograms X ml-1 respectively on Day 1 were not significantly different from the values obtained on Day 8 (tmax 120 min; Cmax 20.7 micrograms X ml-1). The kinetic data suggest that there should be no significant accumulation of tiaprofenic acid in elderly ambulant people suffering from arthritis.
