A kinetic study of sulindac in the elderly.

To study the disposition of the anti-inflammatory drug sulindac, its active sulphide metabolite, and the inactive sulphone metabolite, sulindac (200 mg twice daily) was given to eight elderly subjects for at least 14 consecutive days. The drug was then ceased for 72 hours, and suitable samples were collected to study its elimination. The mean steady-state concentration for sulindac was 5.0 micrograms/ml, for sulindac sulphide was 6.5 micrograms/ml, and for sulindac sulphone was 13.2 micrograms/ml. These are approximately twice the reported steady-state levels for the respective redox forms in healthy young adults. The mean half-lives of sulindac, sulindac sulphide, and sulindac sulphone were 18.3 hours, 22.3 hours, and 54.6 hours, respectively. One patient who had mildly abnormal liver function tests developed more severe abnormalities whilst receiving sulindac. These returned towards normal after cessation of treatment. This patient had the highest steady-state plasma concentration of sulindac sulphone. It is concluded that care should be taken with the use of sulindac in the elderly, and control of patients' symptoms should be attempted with lower doses of the drug before the standard dose of 200 mg twice daily is administered.