Fig. 4. Plasma concentrations of levosimendan and its metabolites, OR-1855 and OR-1896, during and after a 24-h infusion of levosimendan in patients with chronic heart failure. Concentrations of levosimendan decline quickly after discontinuation of the infusion, whereas both metabolites reach maximum plasma concentrations approximately 2 days after withdrawal of levosimendan.  Error bars indicate SEMs. Reprinted with permission from Dustri-Verlag, Inc., from Kivikko  et al. 48