4CPS-160 Lokelma in heart failure patients: safety profile and tolerability –a real-world retrospective cohort study

<h3>Background and Importance</h3> Managing hyperkalaemia in heart failure (HF) patients remains a clinical challenge, often limiting the use of renin-angiotensin-aldosterone system inhibitors (RAASi), essential for optimising HF therapy. Hospital pharmacists play a crucial role in clinical outcomes and drug monitoring. Lokelma (sodium zirconium cyclosilicate) has shown efficacy in controlled clinical trials; yet real-world evidence on safety and short-term outcomes is limited. <h3>Aim and Objectives</h3> Assess the real-world effectiveness of Lokelma in normalising serum potassium in HF patients, monitor its effects on renal function and magnesium levels, and describe its tolerability profile. <h3>Material and Methods</h3> A retrospective, single-centre cohort including 46 adult HF patients started Lokelma therapy between January 2023 and September 2025. Demographic, laboratory, and dosing data were obtained from electronic medical records. The primary endpoint was the proportion of patients achieving serum potassium &lt;5.0 mmol/L at 30 days. Secondary endpoints were changes in eGFR and serum magnesium. Pre- and post-treatment values were compared with paired t-tests; 95% confidence intervals (CI) were calculated, and adverse events were identified through active pharmacovigilance during clinical record monitoring. <h3>Results</h3> Mean age was 74.2 years, 56.5% male. At 30 days, 43.5% achieved target potassium &lt;5.0 mmol/L. Mean potassium decreased from 5.58 to 5.07 mmol/L (mean Δ = -0.51 mmol/L; 95% CI: -0.73 to -0.28; p &lt; 0.001). No significant change in renal function (mean eGFR: 39.5 vs 41.1 mL/min at baseline and 30 days; Δ = +1.55 mL/min; 95% CI: -1.84 to 4.93; p = 0.36) or serum magnesium (2.17 to 2.12 mg/dL; Δ = -0.04 mg/dL; 95% CI: -0.12 to 0.04; p = 0.29) was observed. Hypomagnesaemia (&lt;1.7 mg/dL) occurred in 11.6% of patients (two cases required supplementation). The safety profile was favourable: three patients (6.5%) had adverse events (two with mild gastrointestinal symptoms and one discontinuation due to intolerance, reported to the national system). No serious or fatal events occurred. <h3>Conclusion and Relevance</h3> Lokelma was safe and effective for hyperkalaemia management in HF patients, with no renal toxicity or significant impact on magnesium homeostasis. Its low adverse event rate supports tolerability. Long-term data will clarify the clinical impact of RAASi titration and maintenance of foundational HF treatment. <h3>Conflict of Interest</h3> No conflict of interest