Etripamil (CARDAMYST[TM]) is an intranasal L-type calcium channel blocker (CCB) developed by Milestone Pharmaceuticals for the treatment of symptomatic paroxysmal supraventricular tachycardia (PSVT) and is under investigation for atrial fibrillation with rapid ventricular rate (AF-RVR). It received its first approval on the 12 December 2025 in the USA for the conversion of acute symptomatic PSVT episodes to sinus rhythm in adults. Additional global regulatory filings of etripamil for PSVT in adults, a phase II trial of etripamil in pediatrics, and a phase III trial for AF-RVR are in progress. This article summarizes the milestones in the development of etripamil leading to this first approval for PSVT.