PATIROMER: A NEW POTASSIUM BINDING RESIN. IS IT SAFE AND EFFICACIOUS? Gulshan Dangol, MD; David J Gemmel, PhD; Shreeyukta Bhattarai, MD; Sajana Maharjan, MBBS; Erdal Sarac, MD, FACP Departments of Internal Medicine and Research St. Elizabeth Youngstown Hospital Northeastern Ohio Medical University Rootstown, Ohio Introduction Persistent hyperkalemia is an electrolyte abnormality which is commonly seen in patients with chronic kidney disease (CKD). Persistently elevated potassium (K) has multiple complications, potential for cardiac arrhythmias being one of the most dreaded ones. Thus, keeping the K level within the normal range is essential. Various agents have been approved to decrease the potassium levels. One such agent is patiromer, a new Food and Drug Administration (FDA) approved nonabsorbable potassium-binding polymer, which exchanges Calcium (Ca) for K in the gastrointestinal tract, especially the colon. In this study, we seek to determine the long term safety and efficacy of patiromer in patients with stage III, IV and V CKD. Methods Single center, retrospective cohort study of patients with CKD stage III, IV and V, including those patients on dialysis, who were prescribed patiromer on a daily basis from May 2016 to January 2017. Statistical analysis was done using the paired student’s t test. Results A total of 22 patients, 13 male and 9 female (mean age 69±10 years), were evaluated. Ten patients (45.5%) had CKD III, 8 (36.4%) had CKD IV, and 4 (18.2%) had CKD V and were on dialysis. In addition to kidney failure, use of angiotension converting enzyme inhibitors (ACEi) in patients with diabetes mellitus (n=13, 59.1%), hypertension (n=19, 86.3%) and congestive heart failure (n=2, 9.1%) were additional factors for hyperkalemia in our study. Seven patients (31.8%) were on ACEi. Presence of T cell leukemia (n=3, 13.6%) was another factor that played a role in the development of hyperkalemia in the series. Six patients in the series had concomitant furosemide use, five had concomitant bicarbonate use and three had prior kayexalate use. The baseline K of the patients were 5.7±0.4 mmol/L, Ca was 9.7±0.4 mg/dl, phosphorus (P) was 4.1±0.9mg/dl and magnesium was (Mg) 2.0±0.5 mg/dl. After the administration of patiromer, the lab results were followed. The follow up K was found to be 4.9±0.5 mmol/L (t = 5.4, p <0.001), Ca was 9.3±0.4 mg/dl (t = 2.5, p = 0.025), P was 3.8±0.9 (t = 2.8, p = 0.032) and Mg was 1.9±0.3 (t = 1.3, p = 0.228). Hypercalcemia (Ca 11.6mg/dl) was seen in 1 patient which resolved (Ca 8.4mg/dl) with discontinuation of the drug. Other side effects reported included diarrhea (n=1, 4.5%) and constipation (n=5, 22.7%). Conclusion Patiromer is an efficacious drug with relatively less serious side effects. It can be used with other K lower agents without the potential to cause severe hypokalemia. GI side effects are common. Hypercalcemia, even though a theoretical possibility, occurred in only one patient making it a less probable side effect. However, further investigation with longer duration of follow up is required to adequately determine the safety of the drug. References Weir MR, Bakris GL, Bushinsky DA, Mayo MR, Garza D, Stasiv Y, Wittes J, ChristSchmidt H, Berman L, Pitt B; OPAL-HK Investigators: Patiromer in patients with kidney disease and hyperkalemia receiving RAAS inhibitors. N Engl J Med 2015; 372: 211–221. Bakris GL, Pitt B, Weir MR, Freeman MW, Mayo MR, Garza D, Stasiv Y, Zawadzki R, Berman L, Bushinsky DA; AMETHYST-DN Investigators: Effect of patiromer on serum potassium level in patients with hyperkalemia and diabetic kidney disease: the AMETHYSTDN randomized clinical trial. JAMA 2015; Pitt B, Bakris GL, Bushinsky DA, Garza D, Mayo MR, Stasiv Y, Christ-Schmidt H, Berman L, Weir MR: Effect of patiromer on reducing serum potassium and preventing recurrent hyperkalaemia in patients with heart failure and chronic kidney disease on RAAS inhibitors. Eur J Heart Fail 2015; 17: 1057– 1065. Li L, Harrison SD, Cope MJ, Park C, Lee L, Salaymeh F, Madsen D, Benton WW, Berman L, Buysse J: Mechanism of action and pharmacology of patiromer, a nonabsorbed crosslinked polymer that lowers serum potassium concentration in patients with hyperkalemia. J Cardiovasc Pharmacol Ther 2016; 21: 456– 465. Veltassa (Patiromer) for Oral Suspension (Package Insert). Relypsa, Redwood City, 2015.