Background Hyperkalaemia is a common, potentially life threatening, disorder. Potassium binders (eg, sodium polystyrene sulfonate (Kayexalate)) are the mainstay of hyperkalaemia treatment regimens. However, there is no protocol for the use and monitoring of these drugs in our institution, nor did we find any published guidelines.

Purpose To evaluate the safety of non-protocol based treatment of hyperkalaemia using Kayexalate in internal medicine wards. Our hypothesis was that repeat administration of the drug is associated with higher toxicity than single administration and monitoring.

Material and methods This was a retrospective observational study. The study included all patients treated with Kayexalate during 2013 in internal medicine wards. Patients receiving chronic Kayexalate treatment, and patients treated during anuric shock who died during treatment, were excluded. Patients were divided according to initial computerised treatment order: ‘once’ order (repeated according to laboratory results) or ‘constant’ order (x1/day, or x2/day, etc). Data collected included: pretreatment potassium level, number of doses given until normokalaemia, mean total doses given, hypokalaemia events (potassium levels <3.5 mEq/L), and time to first post-treatment laboratory results. Hypokalaemia was considered treatment related if it occurred during 48 hours post-treatment.

Results A total of 696 treatment events met the inclusion and exclusion criteria of the study. We found significant inter- and intra-ward differences in preference of treatment regimens. Regimen choice of constant orders was associated with higher pretreatment potassium levels (p<0.0001). A total of 91 hypokalaemia events were documented. Hypokalaemia events were significantly more common in the constant versus the once treatment regimens (23.85% vs 6% respectively, p<0.0001). Mean time to first post-treatment laboratory assessment was 14.4 hours. Mean number of doses given until normokalaemia was 1.2 doses, while mean total number of doses was 3.9 doses.

Conclusion Lack of treatment protocol was associated with significant inter- and intra-ward differences in treatment and monitoring regimens. Treatment using constant regimens was significantly associated with superfluous doses and higher treatment related hypokalaemia. In light of these findings, we have developed and implemented an institutional treatment protocol. The post-intervention data are being processed—final results are pending. So far the results show a significant decrease in the number of treatment related hypokalaemia events.

No conflict of interest