Serum sodium concentrations over the course
of the trial are shown in Figure 3. Within 8 hours
after the first administration of tolvaptan, the
serum sodium concentrations were significantly
higher in the tolvaptan group than in the placebo
group for both the total patient population and
the subgroups stratified according to the degree
of hyponatremia at baseline. This statistical superiority
was maintained at all subsequent visits
during the study period within all stratification
subgroups. The serum sodium concentration approached
the normal range more rapidly in the
tolvaptan group than in the placebo group. During
the follow-up week after discontinuation of
the study drug, there was no statistical difference
in the decline in serum sodium concentrations
between the two groups.