Etripamil

Etripamil (brand name Cardamyst) is a novel, fast-acting non-dihydropyridine L-type calcium channel blocker, designed as intranasal (nasal spray) for the on-demand treatment of paroxysmal supraventricular tachycardia (PSVT). It represents a major shift in managing this condition, moving therapy from the hospital to the patient's home. Developed by Milestone Pharmaceuticals, it is the first of its kind, offering a practical and rapid solution to a long-standing medical problem. It is considered a breakthrough nasal spray for a common heart condition.^[1]

When sprayed into the nose, etripamil is rapidly absorbed into the bloodstream. It travels to the heart and specifically targets the AV node. By blocking calcium channels in this node, Etripamil slows down the speed of the electrical signals. Etripamil slows down the heart and breaks the loop, which allows it to return to its normal rhythm (normal sinus rhythm).

Clinical Evidence and Efficacy

Etripamil's effectiveness has been proven in large-scale clinical trials, most notably the RAPID trial. The key findings from these studies showed that:

• High conversion rate: A significantly higher percentage of patients who used Etripamil successfully converted back to a normal heart rhythm within 30 minutes compared to those who used a placebo. Studies showed a conversion rate of around 64% for Etripamil versus 31% for placebo.^[2]
• Rapid onset of action: For most patients, the medication worked quickly, with the median time to conversion being approximately 15-20 minutes.^[3]

This strong clinical evidence demonstrates that Etripamil is both effective and reliable for its intended use.

Furthermore, research is underway to explore Etripamil's use in other heart rhythm conditions, particularly Atrial Fibrillation with Rapid Ventricular Response (AFib-RVR). In this condition, the AV node is also bombarded with rapid signals, and Etripamil's ability to slow conduction could be highly beneficial.^[4][5]

Administration and Safety

Using Etripamil is designed to be straightforward for patients during a stressful PSVT episode. The patient, preferably while sitting or lying down, administers one spray into each nostril.

The most common side effects are typically mild and localized to the nose, such as nasal congestion, discomfort, or a runny nose. Because it is administered nasally and acts quickly, it has a lower risk of causing the widespread systemic side effects that can be seen with intravenous medications.^[6]

The most significant advantage of Etripamil is patient empowerment. It reduces the anxiety and helplessness associated with PSVT episodes and drastically cuts down on costly and time-consuming emergency room visits.^[7]