Conditions: Hyperkalemia
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 32
Healthy volunteers: no

Brief summary:
It is hypothesized that SPS is more effective than placebo control (alternative hypothesis) in lowering i-STAT potassium levels in subjects with i-STAT potassium levels between 5.0 - 6.5 mmol/l versus no difference between SPS and placebo control (null hypothesis).

Detailed description:
Subjects with mild to moderate hyperkalemia (i-STAT potassium levels between 5.0-6.5 mmol/l, inclusive) will be randomized 1:1 in a double-blind fashion to receive placebo or SPS (15g), administered tid with meals for 48 hours. Subjects will come back to the clinic on Study Day 9 for an End of Study (EOS) visit. Adverse experiences will be recorded.

Blood potassium levels will be evaluated by both i-STAT and the Local Laboratory prior to the first dose on Study Days 1 and 2, 1, 2, and 4 hours after the first dose on Study Day 1, 1 and 4 hours after the first dose on Study Day 2 and prior to breakfast on Study Day 3, after 48 hours of treatment.

Subjects who have i-STAT potassium levels \> 6.5 mmol/l on Study Day 1 at the 4 hour post Dose 1 time point will be withdrawn from the study and will receive standard of care. If the i-STAT potassium value is between 6.1 and 6.5 mmol/l at the 4-hour post Dose 1 draw, subjects will be kept in the clinic for another 90 minutes post Dose 2 and another blood draw will be taken and an ECG will be performed. If the i-STAT potassium level is ≥ 6.2 mmol/l at this time point, the subject will be discontinued from the study and standard of care will be instituted. If the i-STAT potassium level is \< 6.2 mmol/l, and the ECG does not show any of the ECG withdrawal criteria (see below), the subject will continue in the study.

Arms:
arm 1: Oral suspension in water of 15g sodium polystyrene sulfonate administered three times (tid) daily for 48 hours without co-administration of Sorbitol. arm 2: Oral suspension of placebo blended with pigment to have the same appearance, taste, odor and mode of administration as SPS.

Interventions: intervention 1: Sodium polystyrene sulfonate intervention 2: Silicified microcrystalline cellulose
Intervention descriptions: intervention 1: Oral suspension in water of 15g sodium polystyrene sulfonate administered three times (tid) daily for 48 hours without co-administration of Sorbitol. intervention 2: Oral suspension in water of placebo administered three times (tid) daily for 48 hours.

Protocol document: