Pharmacokinetic study of fentiazac and its main metabolite hydroxyfentiazac in the elderly

The pharmacokinetics of fentiazac (F, CAS 18046-21-4) and hydroxyfentiazac (OH-F) were estimated in 12 elderly (> 76 years). After an oral single dose of 200 mg F, the plasma and urine profiles were determined using high-performance liquid chromatography with a fluorescence detection. When compared to results obtained in young adults, the maximum plasma concentrations (5.4 +/- 1.9 mg/l) and-the time to reach them were identical. The terminal half-life (7.0 +/- 9.1 h) was longer, due to a slight increase of the apparent volume of distribution and a decrease of the elimination clearance. The findings suggest that the dosage regimen of this drug should be decreased in the elderly. Moreover, the variability of the pharmacokinetics being larger, individual adaptation of the daily dose should be performed.