In the randomized phase , serum potassium was significantly lower during days 8-29 with all 3 zirconium cyclosilicate doses vs placebo ( 4.8 mEq/L [ 95 % CI , 4.6-4 .9 ] , 4.5 mEq/L [ 95 % CI , 4.4-4 .6 ] , and 4.4 mEq/L [ 95 % CI , 4.3-4 .5 ] for 5 g , 10 g , and 15 g ; 5.1 mEq/L [ 95 % CI , 5.0-5 .2 ] for placebo ; P < .001 for all comparisons ) .