How Midazolam Nasal Spray Works for Seizure Clusters

Midazolam nasal spray is a fast-acting rescue medication designed to stop seizure clusters outside of a hospital, without needing an IV or a trip to the emergency room. The FDA-approved version, marketed as Nayzilam, delivers a single 5 mg dose of midazolam into one nostril and begins working within minutes. It was approved in 2019 for people aged 12 and older, making it one of the first intranasal options for seizure emergencies in the United States.¹ But the story of midazolam nasal spray extends well beyond epilepsy, and the practical details of how it works, who benefits most, and where it falls short are worth understanding.

What Seizure Clusters Are and Why a Nasal Spray Matters

Seizure clusters are episodes where a person experiences multiple seizures over a short period, often within hours. They differ from a single isolated seizure because they tend to keep coming in waves, and each additional seizure raises the risk of a medical emergency. For decades, the standard at-home rescue treatment was rectal diazepam, a gel that caregivers administer rectally during or right after a seizure. It works, but it has obvious drawbacks: it requires partial undressing, it can be difficult to give to a seizing person, and for older children and adults it carries a real stigma that makes people reluctant to use it in public or even at all.

Intranasal delivery solves most of those problems at once. A caregiver simply sprays the medication into one nostril while the person is lying on their side. There is no need for an IV line, no need to remove clothing, and the whole process takes seconds. Research consistently finds that intranasal rescue medications can be given faster and more easily than rectal or intravenous alternatives, which matters because speed is the single most important factor in stopping a seizure cluster before it spirals.²

How It Works in the Brain

Midazolam is a benzodiazepine, the same drug class that includes diazepam (Valium) and lorazepam (Ativan). All benzodiazepines work by enhancing the activity of GABA, the brain’s primary “calm down” signal. Specifically, midazolam binds to GABA-A receptors on nerve cells and increases how often chloride channels open. When chloride floods into a neuron, the cell becomes less likely to fire. In a seizure, large networks of neurons are firing uncontrollably; midazolam dials that activity down by making individual neurons harder to excite.³

The nasal route gets midazolam into the bloodstream fast because the inside of the nose is lined with thin, blood-vessel-rich tissue. The drug crosses that lining, enters the blood, and reaches the brain without needing to pass through the digestive system. In healthy volunteers given a concentrated intranasal spray, blood levels of midazolam peaked in about 14 minutes on average, and the bioavailability was roughly 83%, meaning the body absorbed the vast majority of the dose.⁴ Sedation onset can begin within 10 minutes, and peak effects on alertness and coordination typically show up somewhere between 17 minutes and two hours after the spray.⁵

How Well It Stops Seizure Clusters

The pivotal trial that led to FDA approval was a randomized, double-blind study comparing 5 mg midazolam nasal spray to a placebo spray. About 54% of patients treated with midazolam achieved treatment success, defined as seizure termination within 10 minutes with no recurrence for at least six hours. The placebo group hit that mark only about 34% of the time. Seizure recurrence also dropped meaningfully: roughly 38% of midazolam patients experienced a recurrence within 24 hours, compared with about 60% on placebo. The separation between the two groups appeared within the first 30 minutes and held through the full 24-hour observation window.⁶

A meta-analysis pooling data from multiple studies confirmed these results, finding a statistically significant advantage for midazolam nasal spray over placebo, with no meaningful inconsistency across the trials included.⁷ The numbers may look modest at first glance, with a success rate in the mid-50s rather than 90-something percent. That reflects the nature of seizure clusters: these are difficult-to-treat episodes in people whose epilepsy is already hard to control with daily medications. In that context, cutting seizure recurrence nearly in half is a meaningful win.

Side Effects and Safety Profile

The most common complaints are things you would expect from spraying a medication into your nose and from the sedating nature of benzodiazepines. In a large monitoring study of over 450 intranasal midazolam administrations during video-EEG recordings, nasal irritation occurred in about 8% of cases, prolonged drowsiness in roughly 6%, and nausea or vomiting in about 3%. A temporary dip in oxygen levels was measured after about 17% of seizures, but no major heart or breathing emergencies were observed.⁸

Drowsiness is the feature, not just a side effect: midazolam is supposed to calm brain activity, so feeling sleepy afterward is essentially the drug doing its job. Most people return to their baseline level of alertness and coordination within about four hours of a dose. The short duration is actually a selling point compared with some longer-acting benzodiazepines, which can leave patients groggy for much longer.

Paradoxical reactions, where a benzodiazepine causes agitation instead of calm, are rare but documented. A recent randomized trial testing different intranasal midazolam doses in children for procedural sedation recorded one paradoxical reaction in a child given a higher dose.⁹ These reactions are not unique to the nasal route and can happen with any benzodiazepine given by any method, but caregivers should know they exist.

How It Compares to Rectal Diazepam

Head-to-head studies comparing intranasal midazolam with rectal diazepam generally show that the two are equally effective at stopping seizures. One residential-care trial found no difference in how well the drugs worked or how fast they worked, with drowsiness being the most common side effect for both. The key difference was preference: 16 out of 21 patient-caregiver pairs preferred the nasal spray over the rectal gel.¹⁰

In a pediatric home-treatment study, the median time from giving the medication to seizure cessation was about 1.3 minutes shorter with intranasal midazolam, though that difference did not quite reach statistical significance. Caretakers were more satisfied with the nasal spray and reported it was easier to give.¹¹ A separate hospital-based study of caregiver preferences found that parents felt significantly more comfortable with intranasal midazolam, perceived it as easier to use, and considered it more effective than rectal diazepam.¹²

The preference data matters more than it might seem. A rescue medication only works if people actually use it when they need to. If a parent or school nurse hesitates to give rectal diazepam because of embarrassment or logistical difficulty, the delay can let a seizure cluster escalate. A spray that people are willing to use quickly is, in practice, a more effective treatment than a theoretically equivalent one that sits in a drawer.

Use in Children

Children are one of the populations that stand to benefit most from intranasal midazolam, both because seizure clusters are common in pediatric epilepsy and because rectal administration is particularly problematic as kids get older. A systematic review of evidence across community, prehospital, and emergency-department settings concluded that intranasal midazolam was effective and safe for acute seizures in children, with several studies showing a shorter time to seizure cessation compared to rectal diazepam. Fewer children experienced respiratory depression or drops in oxygen saturation with the nasal spray.¹³

A pediatric meta-analysis that compared intranasal midazolam to intravenous or rectal benzodiazepines across 10 studies found an interesting nuance. When you measure the time from hospital arrival to seizure cessation, intranasal midazolam wins by about 3.5 minutes on average, because there is no delay for starting an IV line. But when you measure the time from the moment the drug is actually given to when the seizure stops, the two routes are equivalent.¹⁴ The takeaway is that the nasal spray’s advantage is not that it’s a faster drug; it’s that it’s a faster delivery system. You can give it immediately while an IV would take precious minutes to set up.

One caution in the pediatric prehospital space: a study of paramedic-administered intranasal midazolam at a dose of 0.1 mg/kg found that children needed redosing more often compared to midazolam given by other routes, suggesting that particular weight-based dose may be too low for intranasal use.¹⁵ Dosing for children remains an active area of research, and the FDA-approved product (Nayzilam at 5 mg) is currently indicated only for patients 12 and older.

Does a Stuffy Nose Affect How Well It Works?

This is one of the first questions people ask, and the answer is more reassuring than you might expect. Research into nasal drug absorption has found that common forms of nasal congestion, including allergic rhinitis, infectious rhinitis, and other chronic nasal conditions, do not appear to have a clinically meaningful impact on how well the drug gets absorbed. Studies of intranasal diazepam, which uses a similar delivery route, found that patients with a history of seasonal allergies or rhinitis did not need a second dose any more often than patients without those conditions.¹⁶ That said, severe physical obstruction of the nasal passages, such as from nasal polyps or significant structural abnormality, is a different story, and patients with those issues should discuss alternatives with their neurologist.

Beyond Seizures: Procedural Sedation

Midazolam nasal spray has carved out a role in pediatric procedural sedation, particularly in dentistry. Getting a young child to sit still for dental work is a perennial challenge, and intranasal midazolam offers a needle-free way to achieve mild sedation. The drug typically takes effect within 5 to 15 minutes when sprayed into a child’s nose, making it practical for appointments where the wait needs to be short.¹⁷

It works well for children who are mildly to moderately anxious, but for longer or more invasive procedures, it often isn’t enough on its own. Combining intranasal midazolam with other intranasal agents like ketamine or dexmedetomidine has shown better results in terms of both sedation success and duration of effect.¹⁸ These combination approaches are becoming increasingly standard in pediatric dental practices that want to avoid general anesthesia for routine procedures.

Palliative Care and End-of-Life Agitation

A less-discussed application of intranasal midazolam is in palliative care, where it can be used to manage terminal agitation, the restlessness and distress that many patients experience in the final days of life. German palliative care guidelines already recommend midazolam for this purpose, and the traditional route is subcutaneous injection.¹⁹

A randomized trial directly comparing intranasal midazolam to subcutaneous injection found that both routes effectively reduced agitation, but the intranasal route actually achieved much higher blood levels of midazolam within the first five minutes. Agitation scores dropped significantly in both groups, with the intranasal group reaching a deeper level of calm at the 20-minute mark. No patients in either group were withdrawn because of adverse effects.²⁰ For dying patients who may be needle-averse, who have poor subcutaneous absorption due to edema, or whose families want something they can give without medical equipment, the nasal route offers a gentler alternative.

Prehospital Emergency Use by Paramedics

Paramedics and EMTs have embraced intranasal midazolam as a practical tool for status epilepticus, the dangerous condition where a seizure lasts more than five minutes or multiple seizures occur without recovery in between. In an analysis of emergency medical services data, intranasal administration accounted for about 47% of all midazolam given in the field, more than IV injection at about 38%.²¹ The reason is simple: starting an IV in someone who is actively seizing, possibly on the floor of a grocery store or in the back of a moving ambulance, is difficult and time-consuming. Spraying something into their nose takes seconds.

A systematic review of intranasal medications in prehospital settings noted that while evidence for intranasal fentanyl and ketamine was consistently strong, the evidence for intranasal midazolam in this context was less clear-cut.²² That does not mean it doesn’t work; rather, the trials available are smaller and less uniform than those for pain medications. In practice, EMS agencies across the country use it regularly, and it fills a real gap when IV access is impossible or would take too long.

How Midazolam Nasal Spray Differs From Diazepam Nasal Spray

Since 2020, there have been two FDA-approved intranasal benzodiazepines for seizure clusters: midazolam nasal spray (Nayzilam, approved for ages 12 and up) and diazepam nasal spray (Valtoco, approved for ages 6 and up). They are not interchangeable. The formulations use different chemistry to get the drug across the nasal lining, and diazepam nasal spray has a broader age range.²³ Midazolam itself is shorter-acting than diazepam, which can be an advantage if you want the sedation to clear quickly or a disadvantage if seizure protection needs to last longer. The choice between them often comes down to a neurologist’s assessment of the individual patient’s seizure pattern, age, and tolerance for sedation.

Both intranasal products represent a meaningful step forward from rectal diazepam for the simple reason that people will actually use them when they are needed. Having two options in the same delivery class also gives prescribers flexibility if a patient doesn’t tolerate one formulation or needs broader coverage.