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SZC Onset of Action — ESENeph MCQ

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EasyElectrolyte DisordersSZC Onset of ActionESENeph

A 35-year-old man with type 1 diabetes and CKD G4 has a potassium of 5.8 mmol/L. He is on insulin, Lisinopril, and Fludrocortisone 50 mcg for orthostatic hypotension. His clinician considers Sodium Zirconium Cyclosilicate (SZC). What is the onset of action of SZC?

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Correct answer: A — 1-2 hours – significantly faster than Patiromer, making it suitable for both acute and chronic use

SZC has onset of action within 1-2 hours after oral administration, making it uniquely suitable for both acute hyperkalaemia management (emergency department/acute medical unit setting) and chronic potassium management. This contrasts with Patiromer, which acts primarily in the distal colon with onset of 7-48 hours (chronic use only). SZC 10g stat can be used in acute settings (NICE evidence review supports this), followed by maintenance dosing. The fast onset is due to SZC's action throughout the entire GI tract, not just the colon.

Reference: NICE – SZC Evidence Summary; BNF 2024 – SZC; Kosiborod et al 2014 – HARMONIZE