SINGLE AND MULTIPLE-DOSE PHARMACOKINETICS OF LANSOPRAZOLE IN ELDERLY SUBJECTS

Plasma concentrations of lansoprazole and of its sulphone, sulphide a- nd 5-hydroxylated metabolites were determined after oral administratio n of a single 30 mg dose and after 7 days of treatment with a daily 30 mg dose in 12 elderly subjects (mean age 83 years). Results after a s ingle dose were compared with those from a historical control group of 18 young subjects (mean age 23 years). Mean values of AUC after singl e dose were 2668 ng ml-1 h in the young subjects and 5216 ng ml-1 h in the elderly (P < 0.05). Mean t1/2z values in young and elderly subjec ts were 1.4 h and 2.9 h, respectively (P < 0.001). Plasma concentratio ns of the metabolites were similar in both groups. However, the hydrox ylated metabolite of the sulphone was detected only in elderly subject s. Steady state plasma concentrations of lansoprazole were reached aft er 3 days of dosing with lansoprazole. The accumulation ratio was 1.31 in the elderly subjects.