The U.S. Food and Drug Administration (FDA) has approved CARDAMYST™ (etripamil) nasal spray as the first and only self-administered therapy for adults experiencing acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT). Announced on December 12, 2025, this landmark decision addresses an unmet need for more than two million Americans living with PSVT, who had not had an FDA-approved treatment for over thirty years.
PSVT is one of the common forms of abnormal heart rhythm where the patient experiences sudden bursts of fast heart rate, usually over 150-200 beats per minute, causing palpitations, dizziness, shortness of breath, chest pain, and severe anxiety, which interferes with daily life. Until this approval, treatment options for PSVT were limited and, in most cases, had to be administered in a clinical or emergency setting.
CARDAMYST represents a significant advancement, enabling patients to manage PSVT episodes outside of a healthcare setting, potentially reducing emergency room visits and giving patients greater control over their condition.
CARDAMYST is a novel calcium channel blocker, which is given through a nasal spray that is self-administered, to eliminate PSVT episodes and reestablish normal sinus rhythm quickly. The drug is expected to be available in retail pharmacies in the first quarter of 2026, offering a convenient, on-the-go solution for adults living with PSVT.
The decision to approve the drug was based on a series of extensive clinical trial studies employing over 1800 subjects and over 2000 reported incidences of PSVT, which were conducted in Phase 3 trials and prior studies.
The landmark Phase 3 RAPID trial, an international, randomized, and double-blind trial, which was published in The Lancet in 2023, showed statistically significant effectiveness. During that trial, 64% of those who self-administered CARDAMYST (N=99) had a conversion rate of supraventricular tachycardia to normal sinus rhythm in 30 minutes, as compared to 31% of controls (N=85), with a hazard ratio of 2.62 (p < 0.001). Conversion was attained in 73% of CARDAMYST-treated patients at the one-hour mark. Median time to conversion in CARDAMYST was 17 minutes (95% confidence interval [CI]: 13.4 to 26.5) and in placebo 54 minutes (95% CI: 38.7 to 87.3).
In addition to the RAPID study, combined analyses from the NODE clinical program, presented at the 2025 American Heart Association (AHA) Scientific Sessions, showed comparable results, with a median conversion time of 18.5 minutes and approximately 59.6% of patients achieving sinus rhythm within 30 minutes.
Test dose failure was observed in only 1.4% of patients, and no significant changes in baseline heart rate or blood pressure were reported, underscoring the drug’s high tolerability. The safety data provided by the joint clinical programs revealed that treatment-emergent adverse events were usually mild and short-lived. The most common adverse events that were reported in 5 or more patients treated were nasal discomfort, nasal congestion, rhinorrhea (runny nose), throat irritation, and epistaxis (nosebleeds). Less than 2% of patients were stopping treatment because of adverse events, and the overall tolerability was good in the subgroups (including patients who were taking beta blockers or other calcium channel blockers at the same time).
In statements accompanying the approval, the leaders of Milestone and clinical researchers emphasized that CARDAMYST provides an at-the-ready treatment alternative, which can help overcome the unpredictable effects of PSVT and offer patients the freedom to control the episodes at any time and place.
The physicians who participated in the clinical development reported that the approval will enable a significant number of patients to easily terminate PSVT attacks and, therefore, potentially eliminate emergency treatment. The FDA approval is a major step towards PSVT treatment, offering a new, quick-acting, self-medication treatment that empowers patients and has the potential to change the quality of care of people with this mostly disruptive arrhythmia.
Reference: Milestone PHARMACEUTICALS. Milestone Receives FDA Approval of CARDAMYST™ (etripamil) as First and Only Self-Administered Nasal Spray for Adults with Paroxysmal Supraventricular Tachycardia (PSVT). Published December 12, 2025. Accessed December 15, 2025. Milestone Receives FDA Approval of CARDAMYST™ (etripamil) as First and Only Self-Administered Nasal Spray for Adults with Paroxysmal Supraventricular Tachycardia (PSVT).
