This page shows what was measured, who it was measured in, and what that does not settle.
What Azelastine does in the body
Hay fever, and the non-allergic runny nose that weather, smells and temperature set off
Instead of swallowing an antihistamine and waiting for it to circulate to your nose, you spray it straight onto the lining. It blocks the histamine receptor there within minutes, and it also makes the cells that release histamine less willing to do so, which an oral antihistamine does not. The catch is that the nose is a very absorbent surface: about two-fifths of what you spray ends up in your bloodstream, which is why a nasal spray can still make you sleepy. And a good deal of what you spray runs down the back of your throat, where it tastes strongly bitter.
What happened in people
Reflective total nasal symptom score reduction of 4.4 points against 3.0 on placebo in a pooled analysis of 3,398 patients
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
The limit that matters most
That a nasal spray acts only where it is sprayed — about two-fifths is absorbed and the label carries a driving warning
Where it acts
Nasal mucosa — sprayed directly onto the tissue, though about 40% of the delivered amount is absorbed into the circulation
Kind of result
Symptoms and quality of life
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · 0L591QR10I · read 2026-08-29
Its recorded molecular formula is C22H24ClN3O•HCl, weighing 418.37.
US prescribing information · 97c91a09-98d0-4666-8448-0bd50c02bb14 · read 2026-08-30
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 141 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Sum of morning and evening change from baseline in reflective total nasal symptom score (0-24) over 14 days
✓ The study showed what it set out to show
Who was studied
MP4002 (NCT00651118), MP4004 (NCT00740792) and MP4006 (NCT00883168), pooled
How many people
3398
Study design
Three Phase 3, randomised, double-blind, placebo- and active-controlled, 14 days each
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Combination -5.7, fluticasone -5.1, azelastine -4.4, placebo -3.0; combination superior to each single agent and to placebo, all p<0.001
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. The trials were designed to register the fixed combination, so azelastine appears as an active comparator rather than as the drug under study. On that comparison it is the weakest of the three active arms.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Randomised, double-blind, placebo-controlled, 2 weeks after open-label lead-in
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Azelastine spray P=0.007 and azelastine plus fexofenadine P=0.003 against placebo; the two azelastine arms did not differ
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Enrichment by prior non-response to an oral antihistamine makes the population unusually favourable to a nasal agent, and the trial had no active nasal comparator.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
MP4006 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00883168) · a recorded source, not a stored snapshot
Number of PCR-confirmed SARS-CoV-2 infections during the study
✓ The study showed what it set out to show
Who was studied
CONTAIN (EudraCT 2022-003756-13)
How many people
450
Study design
Phase 2, single-centre, randomised, double-blind, placebo-controlled, 56 days
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
5 of 227 (2.2%) against 15 of 223 (6.7%); odds ratio 0.31 (95% CI 0.11 to 0.87)
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Twenty events in total, one centre, sponsor is the manufacturer and two authors are company employees including the chief executive. An erratum was published. The investigators call for confirmation in larger multicentric trials.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
No evidence of an effect on QTc at two sprays per nostril twice daily for 56 days; oral azelastine 4 mg twice daily produced a mean QTc change of 7.2 msec
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
MP4006 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00883168) · a recorded source, not a stored snapshot
What we know
RNAWiki holds 4 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Azelastine
What a person takes: Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis.
The measurement behind this step
Sprayed onto the nasal mucosa, aimed away from the septum, with the head tilted slightly forward to limit run-off into the pharynx — which is what produces the bitter taste. Onset is within minutes; the ophthalmic form prevents itch within 3 minutes and lasts about 8 hours.
Getting in
Sprayed onto the tissue that is inflamed
The drug lands directly on the lining of the nose rather than travelling there through the bloodstream, which is why it starts working in minutes instead of an hour.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Delivered as a metered nasal spray of the hydrochloride salt. Peak plasma concentration comes at 2 to 3 hours, but local mucosal concentration is immediate and far above anything achievable orally. The ophthalmic formulation shows onset of itch prevention within 3 minutes, which is the same principle applied to the conjunctiva.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
Reaching the cell
About two-fifths of it is absorbed anyway
The nasal lining is thin and richly supplied with blood. A large fraction of the dose crosses into the circulation, so the drug is not confined to the nose in the way the word "topical" suggests.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Systemic bioavailability after intranasal administration is approximately 40%, with a steady-state volume of distribution of 14.5 L/kg and 88% plasma protein binding. Above two sprays per nostril twice daily, Cmax and AUC rise more than proportionally with dose.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
What it acts on
It blocks the histamine receptor on the spot
On the nasal lining it occupies the receptor histamine acts through, stopping the itch, sneeze and runny nose signal at the tissue where it starts.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
H1 receptor antagonism demonstrated in isolated tissues, animal models and humans, given as a racemate with no in vitro difference between enantiomers. The principal metabolite desmethylazelastine is itself an H1 antagonist at 20% to 50% of parent plasma concentration and has a long enough presence to contribute to the twice-daily interval.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
The change it makes
It also quietens the cells that release histamine
Beyond blocking the receiver, it makes mast cells less willing to release their contents in the first place, and damps down two other inflammatory chemical families. This is what oral antihistamines do not do.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
In vitro work in human cell lines demonstrates inhibition of histamine and other mediator release from mast cells, inhibition of leukotrienes and platelet-activating factor, and decreased eosinophil chemotaxis and activation. Leukotrienes are a principal driver of nasal congestion, which is the plausible explanation for the congestion effect an oral H1 blocker cannot match.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
What that does for a person
Total nasal symptoms fall by about four and a half points out of twenty-four
Across three trials in nearly three and a half thousand people, the score summing runny nose, sneezing, itchy nose and blocked nose fell by 4.4 points on this drug against 3.0 on placebo — and by 5.1 on a steroid spray.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Reflective total nasal symptom score, range 0 to 24, summed morning and evening over 14 days: -4.4 (SD 4.8) azelastine, -5.1 (SD 4.9) intranasal fluticasone, -5.7 (SD 5.3) the combination, -3.0 (SD 4.2) placebo, all differences p<0.001 in the pooled analysis of 3,398 patients.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
What that does for a person
The price paid is taste and alertness
One person in five tastes it bitterly and one in nine feels sleepy on it. Neither is a rare reaction; both are ordinary consequences of the route and the molecule.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Bitter taste 19.7% against 0.6% on placebo; somnolence 11.5% against 5.4%; nasal burning 4.1% against 1.7%. Discontinuation for adverse reactions was nonetheless 2.2% on drug against 2.8% on placebo, so within the trials these effects were tolerated rather than treatment-limiting.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Adults and children from five years, sold without a prescription in the United States since June 2021 — the first antihistamine nasal spray to make that switch.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “The safety and effectiveness of Azelastine hydrochloride Nasal Spray for the treatment of symptoms of seasonal allergic rhinitis have been established for patients 5 years and older [ see Adverse Reactions (6.1) and Clinical Studies (14.1) ].”
US prescribing information · 97c91a09-98d0-4666-8448-0bd50c02bb14 · read 2026-08-30
On older people, the label states: “Clinical trials of Azelastine hydrochloride Nasal Spray did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients.”
US prescribing information · 97c91a09-98d0-4666-8448-0bd50c02bb14 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Limited data from postmarketing experience over decades of use with azelastine hydrochloride in pregnant women have not identified any drug associated risks of miscarriage, birth defects, or other adverse maternal or fetal outcomes.”
US prescribing information · 97c91a09-98d0-4666-8448-0bd50c02bb14 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of azelastine hydrochloride in human milk, the effects on the breastfed infant, or the effects on milk production.”
US prescribing information · 97c91a09-98d0-4666-8448-0bd50c02bb14 · read 2026-08-30
Where the result stopped carrying
Azelastine came third of three active arms in the pooled registration analysis, behind fluticasone and behind the combination
Somnolence at more than twice the placebo rate, in a product route chosen partly to avoid systemic effects
Oral azelastine produced a mean QTc change of 7.2 msec at 4 mg twice daily, which is why the marketed forms are topical
The cytochrome P450 isoforms responsible for its metabolism have never been identified, so interaction prediction rests on empirical studies alone
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
Sprayed onto the nasal mucosa, aimed away from the septum, with the head tilted slightly forward to limit run-off into the pharynx — which is what produces the bitter taste. Onset is within minutes; the ophthalmic form prevents itch within 3 minutes and lasts about 8 hours.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold and what that means for what is in the pack.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Bitter taste in 19.7% against 0.6% on placebo and somnolence in 11.5% against 5.4%, with an explicit label caution against driving or operating machinery and against concurrent alcohol or other central nervous system depressants. Nasal burning, epistaxis, paroxysmal sneezing, nausea, dry mouth, fatigue, dizziness and weight increase all occur at ≥2% and above placebo. Discontinuation for adverse reactions was 2.2% against 2.8% on placebo. No effect on QTc over 56 days by the nasal route, against a mean 7.2 msec change on oral azelastine 4 mg twice daily. The P450 isoforms responsible for metabolism have not been identified.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
MP4002 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00651118) · a recorded source, not a stored snapshot
MP4004 — azelastine, fluticasone, MP29-02 and placebo in seasonal allergic rhinitis (NCT00740792) · a recorded source, not a stored snapshot
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Metered nasal spray (0.1% and 0.15%), and a separate ophthalmic solution for allergic conjunctivitis
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
Onset is within minutes; the ophthalmic form prevents itch within 3 minutes and lasts about 8 hours.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
50 products list this as an active ingredient in the United States drug directory. 43 of them contain it and nothing else.
FDA National Drug Code directory · 72603-611 · read 2026-08-29
They are sold as powder, solution/ drops and spray, metered, taken intraocular, nasal and ophthalmic.
FDA National Drug Code directory · 72603-611 · read 2026-08-29
The regulator's established pharmacologic class for it is histamine h1 receptor antagonists [moa] and histamine-1 receptor antagonist [epc].
FDA National Drug Code directory · 72603-611 · read 2026-08-29
36 published labels name it as an active ingredient. 29 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 02257284-4bb1-4fe6-8134-e5a67a645114 · read 2026-08-29
Those labels are classed as human otc drug and human prescription drug.
US prescribing information · 02257284-4bb1-4fe6-8134-e5a67a645114 · read 2026-08-29
AZELASTINE HYDROCHLORIDE is nasal at 3 DOSAGE FORMS AND STRENGTHS Azelastine hydrochloride Nasal Spray is a nasal spray solution., recorded as fda label in effect 2024-05-16 in the United States.
US prescribing information · 97c91a09-98d0-4666-8448-0bd50c02bb14 · read 2026-08-30
Recorded price in US: 0.2765–1.0052 USD per one millilitre, across 10 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Azelastine studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That a nasal spray acts only where it is sprayed — about two-fifths is absorbed and the label carries a driving warning
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That azelastine is the strongest nasal option — the steroid beat it and the combination beat the steroid in the same trials
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the COVID prevention result is established — twenty events, one centre, manufacturer-sponsored, and the authors say so
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That bitter taste drives people off treatment — discontinuation was 2.2% on drug against 2.8% on placebo
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Azelastine are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
In 3,398 patients it beat placebo and lost to the steroid it is usually compared against
In plain words
Three trials run in different pollen seasons compared this spray, a steroid spray, both together, and a dummy. All three active treatments beat the dummy. The steroid beat this drug, and the combination beat the steroid.
What was measured
Change from baseline in reflective total nasal symptom score over 14 days, four-arm comparison
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Three multicentre, randomised, double-blind, placebo- and active-controlled parallel-group trials — MP4002 (NCT00651118), MP4004 (NCT00740792) and MP4006 (NCT00883168) — enrolled 3,398 patients aged 12 and over with moderate-to-severe seasonal allergic rhinitis, each running 14 days in a different allergy season. The primary variable was the sum of morning and evening change from baseline in reflective total nasal symptom score, range 0 to 24. In the meta-analysis, mean reduction was 5.7 (SD 5.3) for the azelastine-fluticasone combination, 5.1 (SD 4.9) for fluticasone propionate, 4.4 (SD 4.8) for azelastine and 3.0 (SD 4.2) for placebo, with the combination superior to each single agent and to placebo at p<0.001. The benefit was present from the first day of assessment and extended to each individual nasal symptom, including in the most severely affected patients.
Written into the record, not signed off as a reviewed claim
A nasal spray with a driving warning, because 40% of it gets into the blood
In plain words
People assume a spray stays in the nose. About two-fifths of this one is absorbed into the circulation, and one patient in nine reported drowsiness against one in eighteen on the dummy spray. The label tells you not to drive on it.
What was measured
That applying an antihistamine topically confines its effect to the site of application — the nasal mucosa absorbs about 40% of the delivered amount, and the somnolence rate and label warning follow from that
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Systemic bioavailability after intranasal administration is approximately 40%, with peak plasma concentrations at 2 to 3 hours and greater-than-proportional increases in Cmax and AUC above two sprays per nostril twice daily. Across six placebo- and active-controlled trials in 391 patients aged 12 and over, somnolence was reported in 45 (11.5%) against 19 of 353 on vehicle placebo (5.4%). The Warnings and Precautions section directs patients to avoid hazardous occupations requiring complete mental alertness such as driving or operating machinery, and to avoid concurrent alcohol or other central nervous system depressants because further decreased alertness and impairment of central nervous system performance may occur. The active metabolite desmethylazelastine reaches 20% to 50% of parent plasma concentration at steady state and is itself an H1 antagonist.
Written into the record, not signed off as a reviewed claim
One patient in five tastes it, against one in a hundred and sixty-six on placebo
In plain words
Bitter taste is the defining complaint about this drug and the numbers are extreme: nearly twenty percent of patients reported it against half a percent on the dummy spray. It did not, however, make more people stop treatment in the trials.
What was measured
Adverse reaction incidence at ≥2% and greater than placebo, six controlled trials
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In placebo-controlled seasonal allergic rhinitis trials at two sprays per nostril twice daily, bitter taste was reported by 77 of 391 patients (19.7%) against 2 of 353 on vehicle placebo (0.6%) — a rate ratio above thirty and by far the largest treatment-attributable difference on the label. Nasal burning was 4.1% against 1.7%, paroxysmal sneezing 3.1% against 1.1%, nausea 2.8% against 1.1% and weight increase 2.0% against 0.0%. Notably, discontinuation due to adverse reactions was 2.2% on azelastine against 2.8% on placebo, so within the trials the taste did not drive people off treatment even though it was overwhelmingly attributable to the drug.
Written into the record, not signed off as a reviewed claim
It worked in people an oral antihistamine had already failed
In plain words
A trial deliberately recruited people who had taken an oral antihistamine for a week and barely improved. The spray helped them. Adding the tablet back on top of the spray added nothing.
What was measured
Change from baseline to day 14 in total nasal symptom score in oral-antihistamine non-responders
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A multicentre, randomised, double-blind, placebo-controlled two-week study opened with a one-week open-label lead-in on fexofenadine 60 mg twice daily. The 334 patients who improved by less than 25% to 33% were randomised to azelastine nasal spray two sprays per nostril twice daily, the same spray plus fexofenadine, or saline placebo spray with placebo capsules. At day 14 both azelastine arms improved total nasal symptom score against placebo — p=0.007 for spray alone and p=0.003 for the combination — and azelastine monotherapy was as effective as azelastine plus fexofenadine on the total score and on each of its four component symptoms.
Written into the record, not signed off as a reviewed claim
A phase 2 trial found fewer COVID infections, on twenty events and one centre
In plain words
A German trial had 450 healthy adults spray either this drug or a placebo three times a day for eight weeks and tested them for COVID twice weekly. Five infections occurred in the drug group and fifteen in the placebo group. That is a real difference and it rests on twenty events at one hospital, in a trial run by the manufacturer.
What was measured
That azelastine nasal spray prevents respiratory viral infection — a single-centre phase 2 result on twenty total events, sponsored and co-authored by the manufacturer, which the investigators explicitly say needs confirmation
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The CONTAIN trial was a phase 2, double-blind, placebo-controlled, single-centre study conducted at Saarland University Hospital from March 2023 to July 2024, randomising 450 healthy adults 1:1 to azelastine 0.1% nasal spray or placebo three times daily for 56 days, with rapid antigen testing twice weekly and PCR confirmation. In the intention-to-treat population, PCR-confirmed SARS-CoV-2 infection occurred in 5 of 227 (2.2%) on azelastine against 15 of 223 (6.7%) on placebo, odds ratio 0.31 (95% CI 0.11 to 0.87). Secondary findings were longer mean time to infection among those infected (31.2 against 19.5 days), fewer PCR-confirmed symptomatic infections (21 of 227 against 49 of 223) and lower PCR-confirmed rhinovirus incidence (1.8% against 6.3%). Adverse events were comparable. The trial sponsor is the manufacturer Ursapharm and two authors are company employees including its chief executive; the authors themselves call for confirmation in larger, multicentric trials. An erratum was published alongside the paper.
Written into the record, not signed off as a reviewed claim
The route was chosen partly to avoid a cardiac effect the oral form actually produces
In plain words
Taken as a tablet, this drug lengthens the heart’s electrical recovery time slightly. Sprayed into the nose for eight weeks, it does not. The nasal route is not only about getting the drug to the nose.
What was measured
That a nasal antihistamine is simply an oral antihistamine delivered closer to the target — the same molecule shows a measurable QTc signal by mouth and none by spray, so the route changes the drug’s risk profile as well as its onset
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In a placebo-controlled study of 95 subjects with allergic rhinitis, two sprays per nostril twice daily for 56 days showed no evidence of an effect on cardiac repolarisation as represented by the corrected QT interval. By contrast, multiple-dose oral azelastine produced a mean QTc change of 7.2 msec at 4 mg twice daily and 3.6 msec at 8 mg twice daily. Interaction studies with erythromycin and ketoconazole found no QTc effect on serial electrocardiograms, and at approximately eight times the maximum recommended nasal amount the drug does not prolong QTc to a clinically relevant extent. The specific cytochrome P450 isoforms responsible for its metabolism have never been identified.
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What is not here
7 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
What was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A phthalazinone H1 antagonist sprayed onto the nasal lining that also suppresses mast cell mediator release — in a meta-analysis of three trials in 3,398 patients it reduced reflective total nasal symptom score by 4.4 points against 3.0 on placebo (p<0.001) while intranasal fluticasone reached 5.1 and the two combined reached 5.7; its systemic bioavailability by that route is about 40%, and 19.7% of patients tasted it bitterly against 0.6% on placebo while 11.5% became somnolent against 5.4%.
Recorded evidence blocks (9)
Q1
On the Azelastine label: indicated for what?
"Azelastine HCl Nasal Spray is indicated for the treatment of the symptoms of seasonal allergic rhinitis in adults and pediatric patients 5 years and older, and for the treatment of the symptoms of vasomotor rhinitis in adults and adolescent patients 12 years and older. Azelastine HCl Nasal Spray is an H 1 -receptor…": indications and usage on Azelastine's label. DailyMed label · 77b20c6b-f30f-42a9-a0ef-d5d0bd3feb56 · 2026-03-26
Q2
18 registered trials of Azelastine — at which phases?
Azelastine's half-life is 22 hours — which schedules were studied?
22 hours, the half-life Azelastine's label states: "Elimination: Based on intravenous and oral administration, the elimination half-life and plasma clearance are 22 hours and 0.5 L/h/kg, respectively." DailyMed label · 77b20c6b-f30f-42a9-a0ef-d5d0bd3feb56 · 2026-03-26
bioavailability 40 %.
Show the evidence
half lifepharmacokinetics
22 hours; Elimination: Based on intravenous and oral administration, the elimination half-life and plasma clearance are 22 hours and 0.5 L/h/kg, respectively.
bioavailabilitypharmacokinetics
40 %; Absorption: After intranasal administration, the systemic bioavailability of azelastine hydrochloride is approximately 40%.
metabolismpharmacokinetics
Metabolism: Azelastine is oxidatively metabolized to the principal active metabolite, desmethylazelastine, by the cytochrome P450 enzyme system.
recorded 2026-03-26 · last checked 2026-09-04
Q6
Which 9 trials of Azelastine posted no result?
Posted no result
9 of 9 completed trials
Registrations
NCT00117832, NCT01368445, NCT00612118, NCT00940953, NCT01190852 and NCT01470053, and 3 more
Completion dates
oldest 2006-10; newest 2023-06-20
Show the evidence
Trial
NCT00117832
2006-10
NCT01368445
2008-04
NCT00612118
2008-05
NCT00940953
2008-05
NCT01190852
2010-10
NCT01470053
2012-11
3 further recorded trials
NCT04264637
2021-03-17
NCT04729517
2023-05-02
NCT05311475
2023-06-20
Q7
At the median, Azelastine's trials enrolled 245 people — anything larger?
Median enrolment
245
Largest enrolment
1791
Registered trials counted
18
Q8
What do 511 spontaneous reports say about Azelastine — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Azelastine appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 511 reaction mentions were counted: treatment failure 363; epistaxis 28; dysgeusia 25; asthma 20. FAERS via Open Targets · CHEMBL1200809 · 2026-06-24
Show the evidence
treatment failure
363
epistaxis
28
dysgeusia
25
asthma
20
nasal discomfort
19
anosmia
12
4 more recorded rows
therapeutic product effect incomplete
12
ageusia
11
nasal congestion
11
sneezing
10
recorded 2026-06-24 · last checked 2026-09-04
Q9
Which 10 reactions does Azelastine's label not list?
ChEMBL 37 — CC BY-SA 3.0 Unported · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 6 source rows
✓ no critical contamination: no quarantine open
✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.