I’ll bet that either you or someone you know carries an EpiPen. I’ll also bet that someone you know has avoided using their EpiPen despite the telltale signs of an anaphylactic reaction. I get it. As much as we know that EpiPens are safe and effective, it goes against human nature to stab yourself in the thigh.
Anaphylaxis is a severe allergic reaction that can rapidly become life-threatening. It’s classically defined by its severity: either at least two systems of the body are involved or at least one that impacts your ABCs (airway, breathing, circulation). Airways can swell, blood pressure can plummet, and symptoms can escalate within minutes. In these situations, epinephrine is the gold-standard treatment. If you're experiencing coughing, wheezing, difficulty breathing, choking, dizziness, faintness, or other signs that suggest your airway or blood pressure may be compromised, the recommendation is straightforward: use the EpiPen. The problem is that humans are not always straightforward.
Why Change a Good Thing?
On paper, the EpiPen works extremely well; it is an intramuscular injection of epinephrine targeting a big muscle, allowing for rapid dispersion through the bloodstream. It begins working almost immediately, although its full effects may take several minutes to develop. Because epinephrine starts wearing off within about 20 to 30 minutes, patients are still advised to seek emergency medical care after using it. Anaphylaxis can return, and additional treatment may be required. So why reinvent the wheel? The answer has less to do with the medication and more to do with human behaviour.
Studies have consistently found that people delay using EpiPens, hesitate to carry them, or avoid using them altogether. Sometimes they underestimate the severity of their reaction. Sometimes they hope symptoms will improve on their own. And sometimes, quite simply, they don't want to use a needle.
This is the problem neffy was designed to solve. The medication itself remains unchanged: epinephrine works wonders by targeting receptors across the body, stimulating peripheral vasoconstriction, bronchodilation, and an increase in heart rate – all of which fight the potentially lethal respiratory arrest and blood pressure drop. It is simply a repackaging of how the epinephrine gets delivered. Researchers have pointed to several limitations of traditional auto-injectors: needle phobia, accidental injuries, improper use, and delayed administration. A nasal spray largely sidesteps those concerns. There is no needle to fear, no risk of accidentally injecting a finger, and arguably fewer opportunities to use the device incorrectly during a stressful emergency.
Approved by Health Canada in April 2026 for patients weighing 30 kilograms (66 pounds) or more, neffy is the first needle-free epinephrine nasal spray available in Canada. The idea is simple: if people are reluctant to use an auto-injector during an emergency, perhaps a nasal spray will remove one of the barriers standing between them and a potentially lifesaving medication.
neffy also has a practical advantage: shelf life. The 2 mg formulation remains stable for up to 2.5 years, up to double that of many traditional epinephrine auto-injectors.
Does neffy Actually Work?
This is where things become slightly more complicated. Health Canada's review concluded that neffy delivers epinephrine into the bloodstream in amounts and at speeds comparable to both EpiPens and traditional intramuscular injections. It also produces the expected increases in heart rate and blood pressure that indicate the medication is doing what epinephrine is supposed to do.
The limitation is that most of the evidence comes from pharmacology studies rather than patients actively experiencing anaphylaxis. Researchers can measure how much epinephrine enters the bloodstream and whether it produces the expected physiological effects, but those measurements are ultimately stand-ins for the outcomes we actually care about: stopping an allergic reaction, preventing complications, and keeping patients out of the hospital. None of the available studies evaluated these outcomes, and comparative data between neffy and traditional epinephrine injections in children are still lacking. As a result, scientists have good reasons to believe neffy should work similarly to an EpiPen, but direct evidence from real-world episodes of anaphylaxis remains limited.
Of note, neffy has been approved and on the market in the United States since 2024 for the general population, and 2025 for the pediatric population. Efforts to assess the so called “real world” performance include a 2025 study out of Japan that monitored neffy’s efficacy in pediatric populations.15 patients were administered neffy following anaphylaxis induced by an oral food challenge, and a single dose elicited the effective response in all 15 cases. Additionally, a surveyfunded by ARS pharmaceuticals reported on the real world effectiveness of neffy in the clinical practice, finding that out of 545 patients treated with neffy, about 90% were effectively treated with a single dose. While the patient-focused studies are still few and far between, the literature that does exist paints a promising picture of this new epinephrine delivery system.
Should You Make the Switch?
For now, don’t rush to replace your auto-injectors, especially if they are not expired. Afterwards, the answer may simply come down to preference. neffy appears to deliver epinephrine similarly to traditional injections, and the side effects reported so far (mostly nasal irritation, sneezing, headaches, and mild throat discomfort) have generally been minor.
However, there are still unanswered questions. neffy is currently more expensive than generic epinephrine auto-injectors, reimbursement varies, and pediatric approval has not yet arrived in Canada.
For decades, EpiPens have ensured efforts to treat anaphylaxis are effective. neffy represents an attempt to make the process more approachable. And in an emergency, the best treatment is not necessarily the one that performs perfectly in a laboratory. It's the one people will actually reach for when they need it.
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