Hyperkalemia: Navigating Inpatient Care and Preventing Recurrence

Hyperkalemia management was a topic of interest at the 54th ASHP (American Society of Health-System Pharmacists) Midyear Clinical Meeting. Todd Brothers, PharmD, BCCCP, BCPS, and Jaclyn Harth, PharmD, presented a comprehensive overview of the treatment of acute and chronic hyperkalemia, which included a clinical case scenario. The presentation highlighted the opportunities for healthsystem pharmacists to intervene and enhance both inpatient and transitional care.

Hyperkalemia can be caused or precipitated by several factors. Occasionally, it is iatrogenic, but sometimes it is attributed to altered potassium transfer, potassium release from the intracellular space, or increased potassium intake. Dr. Brothers stressed that high-risk patients include those who take reninangiotensin-aldosterone system (RAAS) inhibitors, patients with CKD, heart failure, and diabetes or prediabetes. These patients require careful monitoring for hyperkalemia. It is more likely to occur in older adults and is associated with a dozen or so medications, therefore, its treatment has serious repercussions for the Medicare budget and requires careful drug regimen review and monitoring. Dr. Brothers discussed the goal of acute hyperkalemia management, which is to prevent life-threatening sequelae, and highlighted steps involved in treatment. Pharmacists are key to providing drug information and facilitating prompt preparation and proper administration of pharmacologic agents used in clinical practice.

The lecture then shifted gears to chronic hyperkalemia when Dr. Harth took the podium, emphasizing that chronic hyperkalemia follows impaired renal potassium excretion and administration of RAAS inhibitors. Here, the approach is three. It includes adjusting or discontinuing medications that can cause hyperkalemia, adding medications to reduce potassium plasma concentrations, and reducing intake of foods high in potassium. Practitioners need to carefully balance the benefits of utilizing certain agents used in management of heart failure and diabetes with their propensity for causing hyperkalemia.

Clinicians have used sodium polystyrene sulfonate for years, but it has several limitations, including its delayed onset of action, risks when administered with sorbitol, and lack of clinical efficacy data. Two potassium-binding agents that were introduced in the past several years are patiromer and sodium zirconium cyclosilicate (SZC). Patiromer binds potassium in the gastrointestinal (GI) tract to reduce free potassium in the GI lumen. It is an oral powder for suspension that is reconstituted and taken at least 3 hours before or after other oral medications. Notable adverse effects include worsening GI motility and hypomagnesemia. Dr. Harth reviewed the findings of the OPAL-HK study in patients with CKD on RAAS inhibitors with a serum K+ of 5.1-6.5 mmol/L, which showed that RAAS inhibitors were discontinued in 56% of patients in the placebo group and 6% in the patiromer group.

SZC selectively captures potassium in exchange for hydrogen and sodium and increases fecal potassium excretion. It is available as an oral powder for suspension and administered 2 hours before or after other oral medications. SZC may decrease serum concentration of clopidogrel and dabigatran and increase the serum concentration of warfarin. It, too, can slow GI motility, so it should be avoided in patients with constipation, obstruction, or impaction. It contains 400 mg of sodium per 5-gram dose, which can cause edema. Dr. Harth reviewed the findings of the HARMONIZE study in outpatients with a serum K+ of greater than or equal to 5.1 mmol/L, which showed a median time to normalization of 2.2 hours and achievement of normokalemia in 84% of patients at 24 hours and 98% of patients at 48 hours.

Dr. Harth presented clinical pearls and emphasized that patients need to be counseled appropriately and thoroughly to optimize transitions of care. Pharmacists should cover preparation, administration, and storage of potassium binders. They should also be warned about drug—drug and food–drug interactions and dietary considerations. In addition to patient counseling and monitoring, pharmacists have a role in working with their institution to develop appropriate protocols and conduct medication use evaluations to assess and improve current strategies for management of hyperkalemia.