EpilepsyRx

Midazolam

Nayzilam (intranasal) · Seizalam (intramuscular)

DailyMed-verified antiseizure indications

Indication / use

Label / evidence summary
Nayzilam nasal spray: seizure clusters in patients with epilepsy from age 12 years. Seizalam intramuscular injection and the specified 10 mg/0.7 mL intramuscular autoinjector: status epilepticus in adults. Other midazolam formulations have separate labels.
Role
Rescue / acute treatment
Class
1,4-benzodiazepine

Indications checked 26 September 2026. Product, route, age, and treatment-role limits apply. A DailyMed listing alone does not establish FDA approval.

Formulations & strengths

U.S. products unless another country is named. Strengths are per unit or stated volume.

Nayzilam (intranasal)

Product / formulation
midazolam nasal spray
Labeled ages
12 years and older
Clinical context
FDA-labeled acute treatment of seizure clusters in the listed age range.
Dosing boundary
One 5-mg single-use device sprayed into one nostril; a prescribed second 5-mg dose uses a new device in the opposite nostril.
Repeat dose / frequency
If prescribed and the patient has not responded, after 10 minutes in the opposite nostril. Do not repeat for breathing trouble or uncharacteristic excessive sedation. No more than 2 doses per episode; no more than 1 episode every 3 days and 5 episodes per month.
Product pharmacokinetics
Tmax: Median 17.3 minutes (range 7.8–28.2) in healthy adults. Bioavailability: Approximately 44% absolute bioavailability in healthy adults. Terminal half-life: Midazolam median 2.1–6.2 hours; active 1-hydroxymidazolam 2.7–7.2 hours in Nayzilam studies.
Evidence basis
Treatment success: seizure termination within 10 minutes after the initial blinded dose and no seizure recurrence from 10 minutes through 6 hours. U.S. label: 53.7% with Nayzilam versus 34.3% with placebo; absolute difference +19.4 percentage points (p=0.011). Termination within 10 minutes: 80.6% versus 70.1%; no recurrence from 10 minutes through 6 hours: 58.2% versus 37.3%.
Brand & formulation labels

Each link names the product and formulation it covers. Archived labels do not establish current availability.

Dosing & administration

Adult / product-specific schedule
Nayzilam 5 mg in one nostril. Seizalam: 10 mg IM in adults, with continuous respiratory/cardiac monitoring.
Pediatric
Nayzilam from age 12 years: the labeled initial dose is 5 mg. No younger-pediatric or other-route seizure regimen is listed here.
Titration / repeat dosing
Nasal: if needed, 5 mg in opposite nostril after 10 minutes; maximum 2 doses, ≤1 episode/3 days and ≤5/month. Do not repeat with breathing difficulty or uncharacteristic excessive sedation.

Dose adjustment & concentrations

Renal impairment
Renal dysfunction may prolong recovery.
Hepatic impairment
Impaired clearance can prolong sedation.
Serum reference information
No routine serum target for rescue treatment

Safety

Boxed warning
Boxed: opioid-associated respiratory depression, abuse/misuse/addiction, and dependence/withdrawal. No reliable single incidence estimate; risk depends on exposure and co-sedatives. Avoid abrupt withdrawal after repeated use.
Contraindications
Nayzilam: midazolam hypersensitivity and acute narrow-angle glaucoma. Review the separate IM product label.
Serious precautions & monitoring
Nasal rescue requires caregiver training. IV/IM emergency treatment requires airway support capability.

Common / selected adverse effects

  • Nayzilam: somnolence, nasal discomfort, headache and throat irritation.
  • IM status treatment: airway obstruction and respiratory depression require monitored care.

Drug interactions: toxicity & clinical action

Partner / combinationClinical effectClinical action
Moderate/strong CYP3A4 inhibitors (e.g., azoles, clarithromycin, ritonavir)Higher/prolonged midazolam exposure, sedation and respiratory toxicity.Avoid these combinations with Nayzilam; other routes have product-specific precautions.
Opioids / alcohol / other CNS depressantsAdditive profound sedation and respiratory depression.Monitor breathing; follow product-specific second-dose exclusions and emergency plan.

Pregnancy & contraception

Fetal / neonatal risk
Midazolam exposure late in pregnancy or during labor can cause neonatal sedation, respiratory depression or withdrawal. Published benzodiazepine observational data do not show a clear major-malformation association; animal developmental neurotoxicity is reported.
Pregnancy / postpartum monitoring
Monitor exposed newborns for sedation, feeding difficulty and withdrawal.

Clinical evidence

Research summaries describe studied populations and outcomes; they do not add indications or constitute treatment recommendations.

Direct pivotal trial Guideline-supported off-label use

Trial summary

Study design / duration
Nasal: randomized, double-blind, placebo-controlled outpatient cluster trial, 201 treated after test-dose screening; success = termination within 10 minutes and no recurrence through 6 hours. RAMPART: double-blind Phase 3 prehospital noninferiority trial, n=893.
Primary endpoint
Nayzilam treatment success: seizure termination within 10 minutes after the initial blinded dose and no recurrence from 10 minutes through 6 hours. RAMPART used seizure absence without rescue therapy at emergency-department arrival.
Results
Nayzilam: 53.7% versus 34.3% placebo, absolute difference +19.4 percentage points (p=0.011). RAMPART: 73.4% IM midazolam versus 63.4% IV lorazepam, absolute difference +10.0 points in the prehospital route strategy.
Confidence intervals
Nayzilam treatment-success 95% CI: 45.3%–62.2% with active treatment and 23.0%–45.7% with placebo; the label does not give a CI for the absolute difference. Use the RAMPART publication/FDA review for its prespecified noninferiority interval.
Discontinuations
The Nayzilam label does not report a Comparative Phase adverse-event discontinuation rate. Its open-label test-dose phase screened tolerability before the randomized phase, limiting generalizability.
Exposure duration
Nayzilam randomized phase: one outpatient seizure cluster, 6-hour primary window, time to next seizure through 24 hours. RAMPART: a single prehospital status-epilepticus episode through emergency-department arrival.

Trial publications

Comparative evidence

Findings
RAMPART prehospital status trial: seizures absent without rescue treatment at ED arrival in 73.4% IM midazolam vs 63.4% IV lorazepam.

Mechanism of action

  • A 1,4-benzodiazepine that enhances GABA-dependent gating of benzodiazepine-sensitive GABA-A chloride channels at the classical α/γ subunit-interface site. This is distinct from the GABA-binding site and from GABA-B receptors.
  • The classical teaching is increased opening/burst frequency for benzodiazepines versus longer openings for barbiturates. Single-channel behavior depends on preparation and conditions, so this is a useful distinction rather than an absolute kinetic rule.
  • Route, onset, duration, active metabolites and clearance distinguish these drugs clinically, but those pharmacokinetic differences are not separate receptor mechanisms.

Pharmacology

Adult values unless specified. Vd/F denotes apparent oral distribution volume.

Pharmacokinetics

Bioavailability
Nayzilam nasal: approximately 44% absolute bioavailability. IV: 100%; IM absorption is generally high (>90%).
Elimination half-life
Intranasal Nayzilam: median elimination half-life 2.1–6.2 hours. Parenteral values vary with clinical setting and patient factors; do not infer that route alone determines terminal half-life.
Volume of distribution
Nayzilam label: estimated total volume 226.5 L. This is a route/study-specific estimate, not a universal weight-based value.
Active metabolite(s)
Yes: 1-hydroxymidazolam (α-hydroxymidazolam); its glucuronide can accumulate in renal failure and contribute to prolonged effects.
Active-metabolite half-life
1-hydroxymidazolam: 2.7–7.2 hours in Nayzilam studies. The glucuronide half-life exceeded 25 hours in an acute-renal-failure ICU study; do not apply that as a normal-population value.
Protein binding
~97%
Metabolism / elimination
CYP3A4/5

Critical illness, renal failure, hepatic impairment and CYP3A inhibitors can substantially prolong sedation.

Molecular structure

Molecular structure of Midazolam
Principal compound; salt and product forms may differ.
NIH PubChem structure and record ↗

Product history

Initial U.S. approval
1985 (midazolam)
Market / formulation history
1985; Seizalam 2018; Nayzilam 2019 (approval years)
Brands
Nayzilam (intranasal) · Seizalam (intramuscular)
Manufacturer / marketer
Nayzilam: UCB; Seizalam: Meridian Medical Technologies
Generic availability
Yes: injectable/oral products; verify nasal-product availability separately.
Related drugs
1,4-benzodiazepine; route-specific rescue products are not interchangeable.

Sources & review status

Representative sources are selected product labels, not an exhaustive list of generic manufacturers. Consult the exact product and formulation prescribed. Brand-name package inserts are linked separately.

The historical Versed record covers the injectable sedation/anesthesia product; it does not establish a seizure-rescue indication or replace current product labeling.

Indications and DailyMed PDFs checked: 2026-09-26. Other profile sources reviewed: 2026-09-15 · label revision noted at that review: 1/2023. This is a draft reference; final review is pending.