This page shows what was measured, who it was measured in, and what that does not settle.
What Quetiapine does in the body
Schizophrenia and the depressed or high phases of bipolar disorder.
Quetiapine blocks dopamine signalling in the brain, which is what dampens hallucinations and delusions, but it holds on to the dopamine receptor loosely and lets go within hours. It binds much more tightly to the histamine receptor, which is the same receptor an old-fashioned antihistamine hits, and that is why it is so sedating. When the liver breaks quetiapine down it produces a second active molecule that blocks the reuptake of noradrenaline, in the way an antidepressant does, which is the leading explanation for why it works in bipolar depression when most antipsychotics do not.
What happened in people
For bipolar depression, about 58 in 100 had a major improvement versus 36 in 100 without it.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
Its widespread use as a sleep aid has never been approved in any country.
Where it acts
Mesolimbic and mesocortical dopamine synapses, plus histamine H1 and alpha-1 adrenergic receptors throughout the brain and blood vessels
Kind of result
The kind of result is not recorded
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
Its recorded molecular formula is C42H50N6O4S2•C4H4O4, weighing 883.11.
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · 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.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 124 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.
Placebo
A placebo is a dummy treatment given so the real one can be compared with it.
A picture of it, and where the picture fails
A placebo is like a blank control in an experiment.
Where that stops being true. A blank does nothing. People given a placebo often do get better.
What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.
An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.
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.
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.
Mean change from baseline to week 8 in Montgomery-Asberg Depression Rating Scale total score in bipolar I or II depression
Time to discontinuation of assigned antipsychotic for any cause
✗ The study did not show it
Who was studied
CATIE phase 1 (NCT00014001)
How many people
1493
Study design
Phase 4 independent randomised double-blind effectiveness trial, up to 18 months
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
P < 0.001 for shorter time to discontinuation on quetiapine than olanzapine; 82% of the quetiapine arm discontinued, the highest of the five treatments
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Perphenazine, a first-generation drug from 1957, performed similarly to quetiapine, risperidone and ziprasidone. The trial was funded by the National Institute of Mental Health, not by a manufacturer.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral immediate-release tablet and extended-release tablet
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Time to discontinuation for any reason, and proportion with at least minimal improvement on the Clinical Global Impression of Change at 12 weeks
✗ The study did not show it
Who was studied
CATIE-AD (NCT00015548)
How many people
421
Study design
Independent randomised double-blind placebo-controlled trial, up to 36 weeks
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
P = 0.52 for time to discontinuation; CGIC improvement 26% on quetiapine versus 21% on placebo, P = 0.22 across arms
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Discontinuation for intolerability was 16% on quetiapine against 5% on placebo (P = 0.009). The mean daily amount used was 56.5 mg, far below the schizophrenia range.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral immediate-release tablet and extended-release tablet
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Statistical significance not reached between groups; total sleep time rose 124.92 minutes on quetiapine and 72.24 minutes on placebo
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Thirteen completers. This is the only dedicated randomised trial of quetiapine in primary insomnia, which is the use that dominates prescribing.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral immediate-release tablet and extended-release tablet
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Time from randomisation to a depressed event on quetiapine SR compared with placebo in major depressive disorder
✗ The study did not show it
Who was studied
NCT00278941 (quetiapine SR monotherapy, maintenance in major depressive disorder)
How many people
3000
Study design
Phase 3 randomised withdrawal trial
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
No results are posted on ClinicalTrials.gov for this completed study. `endpoint met: false` here records "no posted result", not a missed endpoint.
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. A completed phase 3 trial of 3,000 participants with no results section on the registry. Quetiapine is licensed in the United States only as an adjunct in major depressive disorder, not as monotherapy.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral immediate-release tablet and extended-release tablet
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
RNAWiki holds 5 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
Quetiapine
What a person takes: Oral immediate-release tablet and extended-release tablet.
The measurement behind this step
The immediate-release form has a half-life of about six to seven hours, which is short for a maintenance antipsychotic and is the reason an extended-release tablet was developed and separately approved in 2007. Sedation appears within an hour or two of a dose, which is both the main tolerability complaint in psychiatric use and the entire reason for the off-label sleep use.
Getting in
Swallowed, absorbed fast, and largely gone within a day
The tablet dissolves and the drug reaches its peak in the blood within about an hour and a half. The immediate-release form is short-lived, which is why it was originally given more than once a day and why an extended-release version exists.
──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
Rapid oral absorption with a terminal half-life of roughly 6 to 7 hours for the parent compound and about 12 hours for N-desalkylquetiapine. Plasma protein binding is about 83%. Clearance is hepatic and dominated by CYP3A4, so strong CYP3A4 inhibitors and inducers move exposure substantially.
CATIE — Clinical Antipsychotic Trials of Intervention Effectiveness, schizophrenia (NCT00014001) · a recorded source, not a stored snapshot
Reaching the cell
It crosses into the brain and the liver makes a second active drug
The molecule is fat-soluble enough to cross into the brain. At the same time the liver converts part of it into a related molecule that is also active, and behaves differently from the parent.
╌╌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
CYP3A4 sulfoxidation is the main inactivating route; N-dealkylation produces N-desalkylquetiapine, which circulates at concentrations comparable to the parent and has its own receptor profile, including 3.4 nM affinity for histamine H1 and a 12 nM Ki at the noradrenaline transporter.
CATIE — Clinical Antipsychotic Trials of Intervention Effectiveness, schizophrenia (NCT00014001) · a recorded source, not a stored snapshot
What it acts on
It sits briefly on the dopamine receptor, then lets go
Quetiapine blocks the dopamine receptor that antipsychotics act on, but it holds on weakly and comes off within hours. That fast release is why it causes fewer stiffness and tremor side effects than older drugs, and it is also why the antipsychotic effect is modest.
╌╌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
Low-affinity, fast-dissociating antagonism at dopamine D2 in the mesolimbic and mesocortical pathways, with transient high occupancy after each dose falling well below the extrapyramidal threshold between doses. 5-HT2A antagonism is more sustained than D2 antagonism, which is the basis of the fast-off hypothesis of atypicality.
CATIE — Clinical Antipsychotic Trials of Intervention Effectiveness, schizophrenia (NCT00014001) · a recorded source, not a stored snapshot
The change it makes
It blocks histamine and adrenaline receptors much more tightly
The receptors quetiapine grips hardest are not the dopamine ones. It blocks the histamine receptor, which produces heavy sedation, and the receptor that keeps blood vessels toned, which is why blood pressure can drop on standing.
╌╌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
Histamine H1 antagonism drives somnolence and, over months, appetite and weight gain; alpha-1 adrenoceptor blockade produces orthostatic hypotension and dizziness. The FDA label attributes the somnolence explicitly to H1 antagonism. The affinity ordering — H1 and alpha-1 above 5-HT2A above D2 — is why a small nightly amount sedates without meaningfully blocking dopamine.
CATIE — Clinical Antipsychotic Trials of Intervention Effectiveness, schizophrenia (NCT00014001) · a recorded source, not a stored snapshot
What that does for a person
Symptoms fall on a rating scale, and the metabolite adds an antidepressant effect
Over six to eight weeks, hallucinations, delusions and mania scores come down on the scales the trials use. In bipolar depression the second molecule made by the liver appears to add a separate antidepressant action.
╌╌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
Overall symptom reduction against placebo in acute schizophrenia was a standardised mean difference of 0.44 (95% CrI 0.35 to 0.52) across the pooled randomised evidence. In bipolar depression, MADRS response was 58.2% and 57.6% at the two doses tested against 36.1% on placebo, an effect commonly attributed to noradrenaline transporter inhibition by N-desalkylquetiapine.
CATIE — Clinical Antipsychotic Trials of Intervention Effectiveness, schizophrenia (NCT00014001) · 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 5 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.
People with schizophrenia and bipolar disorder, and, in far larger numbers, people prescribed a small nightly amount for sleep, anxiety, agitation in dementia or post-traumatic stress. None of those last uses is an approved indication anywhere.
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: “Maintenance The safety and effectiveness of quetiapine in the maintenance treatment of bipolar disorder has not been established in pediatric patients less than 18 years of age.”
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-30
On older people, the label states: “Of the approximately 3,700 patients in clinical studies with quetiapine, 7% (232) were 65 years of age or over.”
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-30
On people who are pregnant, the label states: “Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to atypical antipsychotics, including quetiapine, during pregnancy.”
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-30
On people who are breastfeeding, the label states: “8.3 Females and Males of Reproductive Potential Infertility Females Based on the pharmacologic action of quetiapine (D2 antagonism), treatment with quetiapine may result in an increase in serum prolactin levels, which may lead to a reversible reduction in fertility in females of reproductive potential [see Warnings and Precautions (5.15) ].”
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-30
On people with reduced liver function, the label states: “Since quetiapine is extensively metabolized by the liver, higher plasma levels are expected in patients with hepatic impairment.”
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-30
On people with reduced kidney function, the label states: “Clinical experience with quetiapine in patients with renal impairment is limited [see Clinical Pharmacology (12.3) ] .”
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-30
Where the result stopped carrying
The 600 mg arm of BOLDER I gave no more benefit than the 300 mg arm on any efficacy measure
CATIE-AD found no significant efficacy advantage over placebo in Alzheimer disease and a significant excess of intolerability dropout
A completed phase 3 maintenance monotherapy trial in major depressive disorder with 3,000 participants has never posted results
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
Oral immediate-release tablet and extended-release tablet
✎ 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
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S6.
No source is stored against this line.
What is in the pack
The immediate-release form has a half-life of about six to seven hours, which is short for a maintenance antipsychotic and is the reason an extended-release tablet was developed and separately approved in 2007.
✎ 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. The rest of the recorded wording: Sedation appears within an hour or two of a dose, which is both the main tolerability complaint in psychiatric use and the entire reason for the off-label sleep use.
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
The United States label carries a boxed warning for increased mortality in elderly patients with dementia-related psychosis and a boxed warning for suicidal thoughts and behaviours in children, adolescents and young adults. Common effects are somnolence, dizziness, dry mouth, orthostatic hypotension and weight gain. The class carries risks of tardive dyskinesia, neuroleptic malignant syndrome, hyperglycaemia and dyslipidaemia. Cataract monitoring is in the label because of lens changes seen in dogs.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
CATIE — Clinical Antipsychotic Trials of Intervention Effectiveness, schizophrenia (NCT00014001) · 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
Oral immediate-release tablet and extended-release tablet
✎ 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
Sedation appears within an hour or two of a dose, which is both the main tolerability complaint in psychiatric use and the entire reason for the off-label sleep use.
✎ 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
417 products list this as an active ingredient in the United States drug directory. 417 of them contain it and nothing else.
FDA National Drug Code directory · 71335-9697 · read 2026-08-29
They are sold as powder, tablet, tablet, extended release, tablet, film coated and tablet, film coated, extended release, taken oral.
FDA National Drug Code directory · 71335-9697 · read 2026-08-29
The regulator's established pharmacologic class for it is atypical antipsychotic [epc].
FDA National Drug Code directory · 71335-9697 · read 2026-08-29
154 published labels name it as an active ingredient. 154 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · e6e25ef9-2671-489e-8eca-58bedb4f59ab · read 2026-08-29
Quetiapine is film-coated tablets at Tablets: 25 mg, 50 mg, 100 mg, 150 mg, 200 mg, 300 mg, and 400 mg, recorded as prescription product; fda label in effect 2025-06-27 in the United States.
US prescribing information · 01261008-5f42-4844-8a65-d4545a67a309 · read 2026-08-27
Recorded price in US: 0.02293–1.22187 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 137 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.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Quetiapine 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 quetiapine is an evidence-based treatment for insomnia — no regulator has approved it for sleep, and the only dedicated primary-insomnia trial had thirteen completers and no significant difference
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 it calms agitation in dementia — CATIE-AD found 26% improved against 21% on placebo, P=0.22, with three times the intolerability dropout
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 noradrenaline transporter inhibition by the metabolite explains the antidepressant effect — a receptor-panel and mouse-behaviour hypothesis, never tested in people
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 being a second-generation drug makes it more effective than an older one — it ranked below haloperidol on the pooled efficacy estimate
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 Quetiapine 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.
BOLDER I: 58% responded in bipolar depression against 36% on placebo, in 542 patients
In plain words
In an eight-week randomised trial of 542 outpatients with bipolar depression, roughly six in ten improved by half or more on the depression scale, against roughly three and a half in ten on placebo. This is the clearest positive result quetiapine owns.
What was measured
MADRS response and remission rates at 8 weeks, and mean MADRS change from baseline
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Calabrese and colleagues randomised 542 outpatients with bipolar I (n=360) or bipolar II (n=182) disorder in a major depressive episode to quetiapine 600 mg/day, quetiapine 300 mg/day or placebo for eight weeks. The primary measure was mean change in Montgomery-Asberg Depression Rating Scale total score from baseline to week 8; both quetiapine arms separated from placebo statistically from week 1 onward. Response, defined as a 50% or greater MADRS improvement, was 58.2% at 600 mg and 57.6% at 300 mg against 36.1% on placebo. Remission, defined as MADRS 12 or below, was 52.9% in both quetiapine arms against 28.4% on placebo. Treatment-emergent mania was 3.2% on quetiapine and 3.9% on placebo. The higher dose gave no additional benefit over the lower one on any measure, which is a dose-response failure inside a positive trial.
Written into the record, not signed off as a reviewed claim
CATIE: 82% of the quetiapine arm stopped the drug, the worst of five treatments
In plain words
In the largest independent schizophrenia trial ever run, patients were given one of five antipsychotics and followed for eighteen months. More people quit quetiapine than any other drug in the trial, including a 1950s drug it was meant to have replaced.
What was measured
Time to discontinuation of assigned treatment for any cause over 18 months
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
CATIE randomised 1,493 patients with chronic schizophrenia at 57 United States sites to olanzapine, perphenazine, quetiapine, risperidone or ziprasidone for up to 18 months, with time to discontinuation for any cause as the primary outcome. Of the 1,432 who took at least one dose, 74% discontinued before 18 months: 64% on olanzapine, 74% on risperidone, 75% on perphenazine, 79% on ziprasidone and 82% on quetiapine. Time to all-cause discontinuation was significantly longer on olanzapine than on quetiapine (P<0.001) or risperidone (P=0.002). The trial was funded by the National Institute of Mental Health, not by a manufacturer, and perphenazine, a first-generation drug from 1957, performed similarly to quetiapine, risperidone and ziprasidone.
Written into the record, not signed off as a reviewed claim
The commonest reason quetiapine is taken has never been an approved indication
In plain words
Quetiapine is licensed for schizophrenia and bipolar disorder. It is prescribed in far larger numbers as a nightly sleeping aid, and no regulator anywhere has reviewed sleep trials and approved it for that.
What was measured
That quetiapine is an appropriate treatment for insomnia — an inference from sleep-quality secondary endpoints in psychiatric populations, plus one thirteen-patient trial that found nothing significant
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A 2023 systematic review and meta-analysis of 21 clinical trials found low-dose quetiapine improved sleep quality against placebo with a standardised mean difference of -0.57 (95% CI -0.75 to -0.40) and increased total sleep time by 47.91 minutes (95% CI 28.06 to 67.76). Against other psychiatric drugs, the total sleep time difference was -4.19 minutes (95% CI -19.43 to 11.05), which is no difference at all. Adverse events and discontinuation for adverse events were common. The only dedicated double-blind randomised trial in primary insomnia enrolled patients to quetiapine 25 mg or placebo for two weeks and finished with thirteen completers: total sleep time rose 124.92 minutes on quetiapine and 72.24 minutes on placebo, and sleep latency fell 96.16 minutes against 23.72 minutes, with statistical significance not reached between the groups. That is the entire dedicated randomised evidence base for the use that dominates prescribing.
Written into the record, not signed off as a reviewed claim
In dementia the drug lost to placebo on efficacy and beat it on harm
In plain words
Antipsychotics were used for years to calm agitation in dementia. When the government funded a trial to test that, quetiapine was no better than a dummy pill on the main measure, and a pooled analysis of fifteen trials found more deaths on drug than on placebo.
What was measured
That antipsychotics calm agitation in dementia — a practice built on open use and small trials, contradicted by the one large independent randomised trial and offset by a measured mortality signal
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
CATIE-AD randomised 421 outpatients with Alzheimer disease and psychosis, aggression or agitation to olanzapine, quetiapine, risperidone or placebo for up to 36 weeks. Median time to discontinuation for any reason did not differ (quetiapine 5.3 weeks, placebo 8.0 weeks, P=0.52), and minimal improvement on the Clinical Global Impression of Change at 12 weeks was seen in 26% on quetiapine against 21% on placebo (P=0.22 across the four arms). Discontinuation for intolerability was 16% on quetiapine against 5% on placebo (P=0.009). Separately, Schneider and colleagues pooled fifteen randomised placebo-controlled trials, nine of them unpublished, covering 3,353 patients on drug and 1,757 on placebo: death occurred in 3.5% on drug against 2.3% on placebo, odds ratio 1.54 (95% CI 1.06 to 2.23, P=0.02). The FDA added a boxed warning for increased mortality in elderly patients with dementia-related psychosis in 2005, and it applies to quetiapine.
Written into the record, not signed off as a reviewed claim
Ranked eighth of fifteen antipsychotics, statistically level with haloperidol
In plain words
When 212 randomised trials covering 43,049 patients were pooled and the fifteen drugs ranked, quetiapine came eighth. The drug immediately above it was haloperidol, a first-generation antipsychotic from 1967.
What was measured
Standardised mean difference in overall symptom change against placebo, and QTc prolongation in ms
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Leucht and colleagues ran a Bayesian multiple-treatments meta-analysis of 212 blinded randomised trials with 43,049 participants, comparing 15 antipsychotics and placebo for acute schizophrenia. Standardised mean differences against placebo for overall symptom change were clozapine 0.88 (95% CrI 0.73 to 1.03), amisulpride 0.66, olanzapine 0.59, risperidone 0.56, paliperidone 0.50, zotepine 0.49, haloperidol 0.45, quetiapine 0.44 (0.35 to 0.52), aripiprazole 0.43, sertindole 0.39, ziprasidone 0.39, chlorpromazine 0.38, asenapine 0.38, lurasidone 0.33 and iloperidone 0.33. The authors concluded the findings challenge the straightforward split of antipsychotics into first- and second-generation classes. In the larger 2019 update covering 402 trials and 53,463 participants, quetiapine prolonged the QTc interval by 3.43 ms against placebo (95% CrI 0.94 to 6.00), the smallest significant prolongation of the seven drugs that showed one.
Written into the record, not signed off as a reviewed claim
The off-label uses were promoted, and the promotion was settled for US$520 million in 2010
In plain words
The pattern of quetiapine being prescribed for things it was never approved for did not arise on its own. In 2010 the manufacturer settled a United States government case over marketing it for uses the FDA had not approved.
What was measured
That the sleep, anxiety and dementia uses grew organically from clinical experience — the settlement documents a promotional origin for the same list of indications
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The United States Department of Justice announced in April 2010 that AstraZeneca had agreed to pay US$520 million to resolve allegations that it illegally marketed Seroquel for uses not approved as safe and effective by the FDA, including aggression, Alzheimer disease, anger management, anxiety, attention deficit hyperactivity disorder, dementia, depression, mood disorder, post-traumatic stress disorder and sleeplessness. Off-label prescribing by a physician is lawful; promotion of an unapproved use by a manufacturer is not, and this is the mechanism by which a licensed indication and an actual prescribing pattern came apart.
Source
United States Department of Justice, Office of Public Affairs, 27 April 2010: "Pharmaceutical Giant AstraZeneca to Pay $520 Million for Off-label Drug Marketing"
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
The antidepressant effect is credited to a metabolite, from receptor data not trials
In plain words
Quetiapine works in bipolar depression, which most antipsychotics do not. The usual explanation is that the body converts it into a second molecule that behaves like an antidepressant. That explanation comes from test-tube receptor work and mouse behaviour, not from a trial in people.
What was measured
That noradrenaline transporter inhibition by N-desalkylquetiapine causes the observed antidepressant effect — a mechanistic hypothesis supported by binding constants and rodent behaviour, never tested directly in humans
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Jensen and colleagues screened quetiapine, N-desalkylquetiapine and the inactive dibenzothiazepinone against a large panel of G-protein-coupled receptors, ion channels and neurotransmitter transporters. N-desalkylquetiapine had 3.4 nM affinity for histamine H1, inhibited the human noradrenaline transporter with a Ki of 12 nM — roughly a hundred-fold more potently than quetiapine itself — and was ten-fold more potent and more efficacious than quetiapine as a 5-HT1A partial agonist. In mice, N-desalkylquetiapine showed antidepressant-like activity in the tail suspension test at doses as low as 0.1 mg/kg. The chain from a 12 nM transporter Ki and a mouse tail suspension result to the human MADRS change in BOLDER I is inference, and no trial has given the metabolite to people on its own.
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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 weak, short-acting dopamine D2 blocker whose strongest binding is to the histamine receptor that makes people sleepy, which produced a real 8-week antidepressant effect in bipolar depression (58% response versus 36% on placebo in 542 patients) and the highest dropout rate of any arm in the largest independent schizophrenia trial ever run, and which is now taken mostly for insomnia, an indication it has never been approved for in any country.
Recorded evidence blocks (10)
Q2
On the Quetiapine label: indicated for what?
"Quetiapine tablet is an atypical antipsychotic indicated for the treatment of: • Schizophrenia ( 1.1 ) • Bipolar I disorder manic episodes ( 1.2 ) • Bipolar disorder, depressive episodes ( 1.2 ) 1.1 Schizophrenia Quetiapine tablets are indicated for the treatment of schizophrenia. The efficacy of quetiapine tablets in…": indications and usage on Quetiapine's label. DailyMed label · 711f42c5-0719-46de-81fb-3d03801b9ed9 · 2026-08-25
Q3
328 registered trials of Quetiapine — at which phases?
Registered studies posting no result
229 of 328
328 registered studies of Quetiapine: 109 phase4, 107 phase3, 39 phase2, 37 na, 22 phase1, 21 na or unstated, 4 early phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01
737 with a PubMed record
Show the evidence
phase4
109
phase3
107
phase2
39
na
37
phase1
22
na or unstated
21
8 more recorded rows
early phase1
4
completed
230
terminated
40
unknown
35
withdrawn
9
recruiting
8
active not recruiting
3
not yet recruiting
3
recorded 2026-09-01 · last checked 2026-09-04
Q4
44 of Quetiapine's trials stopped: futility/efficacy, accrual/recruitment, funding/business, other?
futility/efficacy (3), accrual/recruitment (22), funding/business (8) and other (11): Quetiapine's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"terminated due to very low recruitment rate (27 June 2006)"; 44 of 328 registered studies
Show the evidence
Trial
NCT00139074
terminated; "terminated due to very low recruitment rate (27 June 2006)"
NCT00174603
terminated; "Unable to recruit subjects"
NCT00257894
terminated; "Enrollment was completed with insufficient sample size for publishable results"
NCT00302770
terminated; "This study was terminated due to poor enrollment"
NCT00315900
terminated; "Investigator closed study and left VAMC."
NCT00396214
terminated; "This trial discontinued on 2 May 2008 due to lack of enrolment"
14 further recorded trials
NCT00457899
terminated; "Study terminated due to poor recruitment"
NCT00486798
terminated; "study was not ethically acceptable to continue and therefore it was finally stopped"
NCT00567866
terminated; "Study was terminated due to insufficient funds"
NCT00584688
terminated; "Lack of Enrollment"
NCT00606541
terminated; "The study was terminated by the sponsor due to budgetary issues"
NCT00622245
terminated; "Human metabolite not yet covered sufficiently by nonclinical data"
NCT00658645
terminated; "Interim analysis showed inadequate efficacy of bifeprunox"
NCT00660595
terminated; "To difficult to recruit patients in the acute setting"
NCT00668265
terminated; "The study was not completed, the funding sponsor lost interest."
NCT00681629
terminated; "Difficulty finding eligible sites/patients; current situation in health policy cause negative effect on existing/planned contracts for integrated care program"
NCT00681668
terminated; "Recruitment behind plan, no increase expected"
NCT00704509
terminated; "Interim analysis showed inadequate efficacy of bifeprunox"
NCT00746421
terminated; "Sponsor withdrew funding"
NCT00771134
terminated; "Study was previously suspended and is now terminated"
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Quetiapine used Quetiapine 600mg — over how long?
studies of Quetiapine used the recorded amount. ClinicalTrials.gov · 2026-09-01
14 recorded entries; human; topically, tablet, rectal; also "Quetiapine 600mg", "Quetiapine (50 mg/day-100mg/day)", "Quetiapine(Seroquel-XR) 50~800mg a day"
Show the evidence
human
NCT00521365
Quetiapine 600mg
NCT00617396
Quetiapine (50 mg/day-100mg/day)
NCT01250847
Quetiapine(Seroquel-XR) 50~800mg a day
NCT01603173
Quetiapine Fumarate Tablets 25 mg
NCT01871701
Quetiapine 100 mg (Seroquel, Tablet)
NCT02131545
topically; Quetiapine 25 mg gel applied topically
8 more recorded rows
humanNCT02131545
tablet; Quetiapine 25 mg tablet by mouth
humanNCT02131545
rectal; Quetiapine 25 mg rectal suppository
humanNCT02901587
Quetiapine (Seroquel XR® 800 mg/day)
humanNCT03465787
Quetiapine XR 600 mg
humanNCT04338321
Quetiapine XR 50 mg
humanNCT04338321
Quetiapine XR 100 mg
humanNCT04338321
Quetiapine XR 150 mg
humanNCT05303935
Quetiapine 50 MG
recorded 2026-09-01 · last checked 2026-09-04
Q6
Quetiapine's half-life is 6 hours — which schedules were studied?
6 hours, the half-life Quetiapine's label states: "Elimination of quetiapine is mainly via hepatic metabolism with a mean terminal half-life of about 6 hours within the proposed clinical dose range." DailyMed label · 711f42c5-0719-46de-81fb-3d03801b9ed9 · 2026-08-25
tmax 1.5 hours; bioavailability 100 %.
Show the evidence
half lifepharmacokinetics
6 hours; Elimination of quetiapine is mainly via hepatic metabolism with a mean terminal half-life of about 6 hours within the proposed clinical dose range.
tmaxpharmacokinetics
1.5 hours; Absorption Quetiapine is rapidly absorbed after oral administration, reaching peak plasma concentrations in 1.5 hours.
bioavailabilitypharmacokinetics
100 %; The tablet formulation is 100% bioavailable relative to solution.
metabolismpharmacokinetics
Elimination of quetiapine is mainly via hepatic metabolism with a mean terminal half-life of about 6 hours within the proposed clinical dose range.
recorded 2026-08-25 · last checked 2026-09-04
Q7
Which 142 trials of Quetiapine posted no result?
Posted no result
142 of 142 completed trials
Registrations
NCT00018642, NCT00305422, NCT00060489, NCT00621647, NCT00223249 and NCT00255879, and 136 more
Completion dates
oldest 2002-03; newest 2023-10-03
Show the evidence
Trial
NCT00018642
2002-03
NCT00305422
2003-01
NCT00060489
2003-09
NCT00621647
2003-11
NCT00223249
2004-08
NCT00255879
2004-08
14 further recorded trials
NCT00018668
2004-09
NCT00015548
2004-10
NCT00014001
2004-12
NCT00229645
2005-04
NCT00043849
2005-06
NCT00083954
2005-08
NCT00085891
2005-09
NCT00254813
2005-09
NCT00328978
2005-09
NCT00124059
2005-10
NCT00214578
2005-10
NCT00208143
2005-12
NCT00232336
2006-01
NCT00449397
2006-01
Q8
At the median, Quetiapine's trials enrolled 72 people — anything larger?
Median enrolment
72
Largest enrolment
1037352
Registered trials counted
318
Q9
What do 15736 spontaneous reports say about Quetiapine — 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.
Quetiapine appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 15736 reaction mentions were counted: suicide attempt 2020; drug abuse 1983; somnolence 1943; drug interaction 1916. FAERS via Open Targets · CHEMBL3188993 · 2026-06-24
Show the evidence
suicide attempt
2020
drug abuse
1983
somnolence
1943
drug interaction
1916
toxicity to various agents
1623
sopor
1469
4 more recorded rows
coma
1268
electrocardiogram qt prolonged
1201
neuroleptic malignant syndrome
1161
weight increased
1152
recorded 2026-06-24 · last checked 2026-09-04
Q10
Which 10 reactions does Quetiapine's label not list?
• Concomitant Use of Strong CYP3A4 Inhibitors: Reduce quetiapine dose to one sixth when coadministered with strong CYP3A4 inhibitors (e.g. ketoconazole, ritonavir) ( 7.1 , 12.3 ) • Concomitant Use of Strong CYP3A4 Inducers: Increase quetiapine dose up to 5 fold when used in combination with a chronic treatment (more than 7 to 14 days) of potent CYP3A4 inducers (e.g. phenytoin, rifampin, St.
drug_interactions
John's wort) ( 2.6 , 7.1 , 12.3 ) • Discontinuation of Strong CYP3A4 Inducers: Reduce quetiapine dose by 5 fold within 7 to 14 days of discontinuation of CYP3A4 inducers ( 2.6 , 7.1 , 12.3 ) 7.1 Effect of Other Drugs on Quetiapine The risks of using quetiapine in combination with other drugs have not been extensively evaluated in systematic studies.
drug_interactions
Quetiapine exposure is increased by the prototype CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, indinavir, ritonavir, nefazodone, etc.) and decreased by the prototype CYP3A4 inducers (e.g, phenytoin, carbamazepine, rifampin, avasimibe, St.
drug_interactions
Dose adjustment of quetiapine will be necessary if it is co-administered with potent CYP3A4 inducers or inhibitors.
drug_interactions
CYP3A4 Inhibitors Coadministration of ketoconazole, a potent inhibitor of cytochrome CYP3A4, resulted in significant increase in quetiapine exposure.
drug_interactions
The dose of quetiapine should be reduced to one sixth of the original dose if co-administered with a strong CYP3A4 inhibitor [see DOSAGE AND ADMINISTRATION ( 2.5 ) and CLINICAL PHARMACOLOGY ( 12.3 )].
2 more recorded rows
Interaction statementdrug_interactions
CYP3A4 Inducers Coadministration of quetiapine and phenytoin, a CYP3A4 inducer increased the mean oral clearance of quetiapine by 5-fold.
Interaction statementdrug_interactions
Increased doses of quetiapine up to 5 fold may be required to maintain control of symptoms of schizophrenia in patients receiving quetiapine and phenytoin, or other known potent CYP3A4 inducers [see DOSAGE AND ADMINISTRATION ( 2.6 ) and CLINICAL PHARMACOLOGY ( 12.3 )].
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
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