Sodium polystyrene is unsafe and should not be prescribed for the treatment of hyperkalaemia: primum non nocere!

‘Old-generation’ potassium (K) binders [i.e. sodium (SPS) and calcium polystyrene sulfonate] are widely used, but with substantial heterogeneity across countries to treat hyperkalaemia (HK). However, there are no randomized data to support their chronic use to manage HK, nor have they been shown to have a renin–angiotensin–aldosterone system inhibitor (RAASi)-enabling effect. These compounds have poor tolerability and an unpredictable onset of action and magnitude of K lowering. Furthermore, SPS may induce fluid overload, owing to the fact that it exchanges K for sodium. Its use has also been associated with colonic necrosis, as emphasized by a black box warning from the US Food and Drug Administration. In contrast, two new K binders, patiromer and sodium zirconium cyclosilicate, have been shown to be safe and well tolerated for chronic management of HK, thereby enabling RAASi optimization, as acknowledged by the latest international cardiorenal guidelines. In view of the lack of reliable evidence regarding the efficacy and safety of the old-generation K binders compared with the placebo-controlled randomized and real-word evidence demonstrating the safety, efficacy and RAASi-enabling effect of the new K binders, clinicians should now use these new K binders to treat HK (primum non nocere!).