(A) Radioactive phosphate and (B) radioactive mannitol absorption in vivo in rats after treatment with vehicle (acidified water, 0.01% Tween 80) or different doses of tenapanor. dpm, disintegrations per minute; AUC, area under the curve. (C) Small intestinal glucose content after initiation of a standardized meal in rats pretreated with vehicle or tenapanor (0.15 mg/kg) or vehicle (acidified water, 0.01% Tween 80) (n = 4 to 7 per group). (D) Stool and (E) urinary phosphorus, (F) urinary sodium, and (G) urinary potassium excretion at baseline (day −1) and after 4 days of tenapanor treatment [15 mg twice daily (b.i.d.)] in healthy volunteers. Means ± SEM (A to C), means ± SD (D to G). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; two-way ANOVA, with post hoc testing at time point with Bonferroni’s correction (A to C); pairwise comparisons by Student’s t test (D to G).