*Purpose: Hyperkalemia, a potentially life‐threatening electrolyte abnormality, is commonly seen SOT. The predisposing factors are renal-dysfunction, and medications (CNI, TMP-SMX, ACEI, and ARBs). Patiromer, a potassium-calcium cation exchanger, has been widely used for hyperkalemia in the general population, but studies are meager in SOT. Our retrospective study is the first to assess the efficacy, safety, and drug-interaction of patiromer in SOT.

*Methods: We conducted a retrospective, single-center study in 37 adult SOT who received patiromer for at least one month from 1/2015 to 8/2019. The primary endpoints were change in potassium (K) levels from baseline to 4, and 12 weeks, and difference of tacrolimus levels at baseline, 4, and 12 weeks. We assessed gastrointestinal (GI) side effects, electrolyte abnormalities, and insurance coverage of patiromer as secondary outcomes.

*Results: Most recipients were kidney (73%), followed by liver (21%), kidney-pancreas (3%), and lung (3%) transplants. The median time for patiromer initiation was 165 days post-transplant but was started as early as 10-days. There was a statistically significant improvement in K levels at both four weeks (5.44 to 4.99, p-value 0.0004) and 12 weeks (5.44 to 5, p-value 0.014). At the end of 4 weeks, 60% were able to achieve goal K of <5.2mmol/L and 44% at 12 weeks. Most recipients were able to reach the goal K within a median of 9 days (min 0 and max 208). One patient required a patiromer dose increase to 25.2 gm, while 97% of recipients remained on the same dose of 8.4 gm throughout the treatment. We noted a statistically significant increase in Tacrolimus levels at four weeks post-patiromer initiation (increased to 9.22 from baseline of 7.19, p-value 0.02) and 32% patients required dose adjustment for that. The majority of patients had no reported GI side-effects, and constipation was seen inconsistently (8%) seen. Hypomagnesemia was the most frequent side-effect affecting 65%, whereas hypercalcemia occurred in 8%. The incidence of hypomagnesemia was higher compared to the general population (5-9%) likely due to the concomitant use of CNIs (renal wasting). Unlike SPS, there were no reported incidences of bowel-necrosis and thus may be safe in new transplants. 46% of patients discontinued patiromer at the end of the study. The resolution of hyperkalemia was the commonest reason (21%), followed by the insurance non-coverage, side-effects, and cost. Insurance coverage was obtained for 81% of recipients, whereas the others required the use of patient-assistance programs.

*Conclusions: Our study demonstrates that patiromer is an effective, rapid, and safe way of treating hyperkalemia in different organ-transplants. The transplant providers should be aware of the possible increase of tacrolimus levels and hypomagnesemia, both of which were easily manageable.

« Back to 2020 American Transplant Congress