What Was Approved?
On December 12, 2025, the U.S. Food and Drug Administration approved Cardamyst (etripamil) nasal spray for the conversion of acute symptomatic paroxysmal supraventricular tachycardia, or PSVT, to sinus rhythm in adults.
PSVT is a type of rapid heart rhythm that can start and stop suddenly.
How Is Cardamyst Used?
Cardamyst is designed for intranasal use.
The initial dose is 70 mg, given as:
- One spray in each nostril
If symptoms continue after 10 minutes, a second 70 mg dose may be used.
The total dose should not exceed 140 mg within 24 hours.
Can Patients Use It Outside a Hospital?
Yes, appropriately selected patients may self-administer Cardamyst when a PSVT episode occurs.
In the clinical trial supporting approval, patients used the medication in a medically unsupervised setting after receiving appropriate instructions.
What Did the Clinical Trial Show?
FDA approval was supported by the RAPID trial, which included 255 adults with documented PSVT.
Within 30 minutes:
- About 49.6% of patients receiving Cardamyst converted to sinus rhythm
- About 22.7% receiving placebo converted to sinus rhythm
These results describe the study population and do not guarantee that every episode will respond.
What Are Common Side Effects?
The most common adverse effects were nasal reactions, including:
- Nasal discomfort
- Nasal congestion
- Runny nose
- Nosebleed
In the clinical safety data summarized by FDA, nasal reactions occurred more often with Cardamyst than with placebo.
Is Cardamyst for Every Fast Heartbeat?
No.
Cardamyst is specifically approved for acute symptomatic PSVT in adults.
It should not be assumed to treat every type of rapid or irregular heart rhythm.
Patients should have an established treatment plan with their healthcare professional and should know when symptoms require emergency medical evaluation.
Bottom Line
Cardamyst (etripamil) is an FDA-approved nasal spray for adults with acute symptomatic PSVT.
It can be self-administered in appropriately selected patients and may help restore sinus rhythm without an immediate intravenous medication, but it is not a treatment for every type of tachycardia.
Sources
- U.S. Food and Drug Administration (FDA) — Drug Trials Snapshot: Cardamyst.
- U.S. Food and Drug Administration (FDA) — Cardamyst (etripamil) Prescribing Information, December 2025.
- U.S. Food and Drug Administration (FDA) — Novel Drug Approvals for 2025.