Quetiapine

Pronunciation: kwe-TYE-a-peen.

Generic name
quetiapine fumarate
Drug class
Atypical antipsychotic (dibenzothiazepine derivative)
Form
Immediate-release tablet (25 mg, 50 mg, 100 mg, 200 mg, 300 mg, 400 mg); extended/prolonged-release tablet (50 mg, 150 mg, 200 mg, 300 mg, 400 mg)
Route
Oral
Legal status
Prescription-only

Supply Rules Vary

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: SEROQUEL (6), SEROQUEL XR (6) · Full directory

What quetiapine fumarate is and how it works

Quetiapine is a prescription-only atypical antipsychotic medicine. It is approved across all 6 markets reviewed to treat schizophrenia, manic episodes of bipolar disorder, and depressive episodes of bipolar disorder (bipolar depression). The extended-release form (Seroquel XR in the US, Seroquel XL in the UK) is additionally approved as an add-on treatment for major depressive disorder (MDD) in adults who have not responded adequately to antidepressant treatment alone -- this MDD-adjunct use does not apply to the immediate-release tablet. (1)

Quetiapine carries two real parts to its US boxed warning -- the FDA's strongest safety warning. The first concerns an increased risk of death in elderly people with dementia-related psychosis; quetiapine is not approved for that use. The second concerns an increased risk of suicidal thoughts and behaviour in children, adolescents, and young adults, which is relevant because quetiapine itself is used to treat bipolar depression. Your prescriber will discuss both risks with you and monitor you closely, especially early in treatment or after a dose change. Quetiapine can also affect blood sugar, cholesterol, and weight, and requires regular monitoring throughout treatment.

Mechanism of action: how quetiapine fumarate works

Quetiapine's mechanism of action in schizophrenia and bipolar disorder is not fully established, but is thought to be mediated through a combination of dopamine D2 and serotonin 5-HT2A receptor antagonism, along with activity at other serotonergic (5-HT1A), histaminergic (H1), and adrenergic (alpha-1) receptors, contributing to its sedative and metabolic effects. (1) (2)

What quetiapine fumarate is used for

Schizophrenia

Approved for the treatment of schizophrenia in adults in all 6 markets reviewed, and in adolescents 13-17 in the United States. (1) (2) (5) (6) (7)

Bipolar mania (acute manic episodes)

Approved for acute manic episodes associated with bipolar I disorder in adults (all 6 markets) and children/adolescents 10-17 (United States), as monotherapy or adjunctive therapy with lithium or divalproex/valproate. (1) (2) (5)

Bipolar depression

Approved for major depressive episodes associated with bipolar disorder in adults, as monotherapy or maintenance therapy adjunctive to mood stabilizers, across all 6 markets reviewed. This is the indication responsible for the second (suicidality) part of the US boxed warning. (1) (2) (7)

Recurrence prevention in bipolar disorder

Approved for prevention of recurrence of manic or depressive episodes in bipolar disorder patients who have previously responded to quetiapine treatment. (2) (3)

Adjunctive treatment of major depressive disorder (extended-release product only)

Seroquel XR (United States) and Seroquel XL (United Kingdom) are approved as add-on treatment for major depressive disorder (MDD) in adults with an inadequate response to antidepressant therapy alone. This indication is NOT approved for the immediate-release Seroquel tablet. (1) (3)

Before taking quetiapine fumarate

Do not take / not appropriate for

  • Do not take quetiapine if you have had an allergic reaction to it or any of its ingredients. (all confirmed markets) (1) (2)
  • Do not take quetiapine with strong CYP3A4 inhibitors (e.g. ketoconazole, HIV protease inhibitors, azole antifungals, erythromycin, clarithromycin, nefazodone) or grapefruit juice -- these are listed as an ABSOLUTE CONTRAINDICATION in the UK SmPC (the current US label treats this as a dose-adjustment caution rather than an absolute contraindication -- always follow your own country's product information and your prescriber's guidance). (United Kingdom (contraindication); United States (caution)) (2) (1)
  • Quetiapine is not approved for treating psychosis related to dementia, and is not indicated in elderly patients with dementia. (all confirmed markets) (1) (5) (6)

Tell your clinician about

  • If quetiapine is being used to treat bipolar depression, whether you (or the person being treated) are a child, adolescent, or young adult -- this use carries a real risk of increased suicidal thinking and behaviour that needs close monitoring.
  • Any personal or family history of heart disease, irregular heartbeat, or QT prolongation.
  • Any history of diabetes, high blood sugar, or high cholesterol.
  • Any personal or family history of movement disorders or seizures.
  • Any history of low white blood cell count or blood disorders.
  • Any history of falls, fainting, or low blood pressure on standing.
  • All other medicines you take, especially CYP3A4 inhibitors or inducers, MAOIs, SSRIs, or SNRIs.
  • Kidney or liver problems.
  • Pregnancy, plans for pregnancy, or breastfeeding.
  • Any history of cataracts or eye problems -- periodic eye exams are recommended during long-term treatment.
(1) (2)

How to take quetiapine fumarate

  • Take quetiapine exactly as prescribed. Immediate-release tablets are usually taken twice daily (schizophrenia, bipolar mania) or once daily at bedtime (bipolar depression); extended-release tablets are taken once daily, without food, and must be swallowed whole -- never split, chewed, or crushed.
  • Do not change your dose or stop taking quetiapine suddenly without talking to your prescriber first -- abrupt discontinuation can cause withdrawal symptoms such as insomnia, nausea, and vomiting; gradual tapering (typically over 1-2 weeks) is generally advised.
  • Avoid grapefruit and grapefruit juice, which can affect quetiapine levels (an absolute contraindication in the UK).
  • Attend all follow-up appointments so your prescriber can monitor for weight, blood sugar, cholesterol, movement changes, and mood or behaviour changes.
(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7)

Missed dose

If you miss a dose, take it as soon as you remember, unless it is almost time for your next dose -- in that case, skip the missed dose and continue your regular schedule. do not take an extra dose. Contact your prescriber if you are unsure or have missed multiple doses, especially before restarting after a longer gap.

Overdose

Seek urgent medical attention or contact a poison control centre if too much quetiapine may have been taken, or if you develop severe drowsiness, an irregular heartbeat, seizures, or fainting. QT prolongation has been reported post-marketing, notably with overdose. There is no specific antidote; management is supportive with cardiac monitoring. (1) (2)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Somnolence (sleepiness) -- very common, one of the most frequently reported effects across indications.

What to notice: Somnolence (sleepiness) -- very common, one of the most frequently reported effects across indications.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Dry mouth, dizziness, constipation -- common across indications.

What to notice: Dry mouth, dizziness, constipation -- common across indications.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Weight gain -- common; about 23% of adults gained 7% or more of body weight in schizophrenia trials.

What to notice: Weight gain -- common; about 23% of adults gained 7% or more of body weight in schizophrenia trials.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Postural (orthostatic) hypotension, asthenia, abdominal pain, elevated liver enzymes (ALT) -- common.

What to notice: Postural (orthostatic) hypotension, asthenia, abdominal pain, elevated liver enzymes (ALT) -- common.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

In pediatric patients: increased appetite, nausea, vomiting, tachycardia, and weight increase reported more frequently than in adults.

What to notice: In pediatric patients: increased appetite, nausea, vomiting, tachycardia, and weight increase reported more frequently than in adults.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)

Serious warnings

Increased risk of death in elderly patients with dementia-related psychosis — boxed_warning

Symptoms: This is a population-level risk identified in clinical trials of antipsychotic medicines as a class, not a specific symptom to watch for.

Action: Quetiapine is not approved for treating dementia-related psychosis. In the US FDA analysis of 17 placebo-controlled trials, the death rate was about 4.5% in drug-treated patients vs about 2.6% in placebo-treated patients (a 1.6-1.7-fold increase). The UK SmPC cites a similar finding (5.5% vs 3.2%), and Australia's TGA product information cites figures matching the US label. Discuss the risks and benefits carefully with the prescriber if this medicine is being considered for an older adult. (1) (2) (6)

Increased risk of suicidal thoughts and behaviour in children, adolescents, and young adults — boxed_warning

Symptoms: New or worsening depression, anxiety, agitation, irritability, hostility, aggressiveness, impulsivity, or thoughts of self-harm or suicide.

Action: This applies specifically when quetiapine is used to treat bipolar depression. Monitor closely for these signs, particularly early in treatment or after a dose change, and contact a prescriber or emergency services immediately if they occur. (1) (2)

Signs of neuroleptic malignant syndrome — emergency

Symptoms: High fever, severe muscle stiffness, altered mental status, rapid or irregular heartbeat, sweating, elevated creatine phosphokinase.

Action: Seek emergency medical attention immediately. Quetiapine should be discontinued right away if this is suspected, with intensive symptomatic treatment and monitoring. (1) (2)

QT interval prolongation and irregular heartbeat — high caution

Symptoms: Palpitations, dizziness, fainting, or an irregular heartbeat.

Action: Tell your prescriber if you have heart disease, a family history of QT prolongation, or electrolyte abnormalities, or if you take other medicines that can prolong the QT interval. QT prolongation has been reported with quetiapine at therapeutic doses and notably in overdose. Seek medical attention for any of these symptoms. (2) (1)

New or worsening high blood sugar, diabetes, or high cholesterol — moderate caution

Symptoms: Increased thirst, frequent urination, unexplained weight gain or loss, fatigue.

Action: Your prescriber will monitor blood sugar, cholesterol, and weight during treatment. Rare cases of severe hyperglycemia with ketoacidosis or hyperosmolar coma have been reported. Tell your prescriber promptly if you notice these symptoms. (1) (2)

Low white blood cell count (leukopenia, neutropenia) or agranulocytosis — high caution

Symptoms: Fever, sore throat, mouth sores, signs of infection, or unusual tiredness.

Action: Tell your prescriber immediately. Blood counts should be monitored, particularly in patients with a pre-existing low white blood cell count or history of drug-induced leukopenia/neutropenia. (1) (2)

Signs of tardive dyskinesia — high caution

Symptoms: Uncontrollable, repetitive body movements (such as grimacing, tongue movements, or lip smacking).

Action: Tell your prescriber promptly -- this may be irreversible in some cases and its likelihood generally increases with treatment duration and cumulative dose. (1) (2)

Severe skin reactions — emergency

Symptoms: Widespread blistering or peeling skin rash, mouth or eye sores, flu-like symptoms preceding a rash.

Action: Seek emergency medical attention immediately -- Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported, and quetiapine should be stopped only on the advice of the emergency medical team or your prescriber. (2)

Serotonin syndrome (when combined with other serotonergic medicines) — emergency

Symptoms: Agitation, rapid heartbeat, high body temperature, muscle rigidity, sweating, tremor, or confusion.

Action: Tell your prescriber about all other medicines you take, especially MAOIs, SSRIs, or SNRIs. Seek emergency medical attention if these symptoms occur -- this is a potentially life-threatening condition. (2)

Cataracts and lens changes — moderate caution

Symptoms: Blurred vision or other vision changes.

Action: A baseline eye examination and periodic exams (approximately every 6 months) are recommended during chronic treatment to check for cataract development. (1)

Falls and orthostatic hypotension — moderate caution

Symptoms: Dizziness, lightheadedness, or fainting on standing up, especially at the start of treatment or after a dose increase.

Action: Tell your prescriber, particularly if you have heart or blood vessel disease, are dehydrated, or take blood pressure medicines. Rise slowly from sitting or lying positions. (1) (2)

Interactions

  • Strong CYP3A4 inhibitors (e.g. ketoconazole, HIV protease inhibitors, azole antifungals, erythromycin, clarithromycin, nefazodone): ABSOLUTE CONTRAINDICATION in the UK (a 5-8 fold increase in quetiapine exposure reported with ketoconazole); framed as a dose-adjustment caution (lower doses may be needed) in the current US label -- follow your own country's guidance. (2) (1)
  • Hepatic enzyme inducers (e.g. carbamazepine, phenytoin): significantly increase quetiapine clearance -- carbamazepine reduced exposure to about 13% of baseline; phenytoin increased clearance by about 450%. Higher quetiapine doses may be required. (2) (1)
  • Grapefruit and grapefruit juice: contraindicated in the UK; can inhibit CYP3A4 and increase quetiapine concentrations. (2)
  • MAOIs, SSRIs, SNRIs, and other serotonergic medicines: increased risk of serotonin syndrome, a potentially life-threatening condition. (2)
  • Other CNS-acting medicines and alcohol: additive sedative effects; caution advised. (1)
  • Antihypertensive medicines: quetiapine may potentiate their blood-pressure-lowering effect. (1)
  • Levodopa and dopamine agonists: quetiapine may antagonize their therapeutic benefit. (1)
  • Urine drug screens: quetiapine may cause false-positive results for methadone and tricyclic antidepressants. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

A moderate amount of published data on first-trimester human exposure does not suggest an increased risk of birth defects, though a definite conclusion cannot be drawn from available data. Third-trimester exposure to antipsychotics including quetiapine may cause extrapyramidal and/or withdrawal symptoms in newborns (agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, feeding disorder). Use in pregnancy only if clearly necessary, weighing benefits against risks. (1) (2) (3) (4) (5) (6) (7)

Breastfeeding

Data on excretion into human breast milk are limited; a clinical decision balancing the mother's need for treatment against potential effects on the breastfed infant is required. (1) (2) (3) (4) (5) (6) (7)

Children

Approved uses in children/adolescents vary by market and product: schizophrenia and bipolar mania from age 10-13 depending on the indication and market (US); not established for irritability associated with autistic disorder or other unapproved pediatric uses. Pediatric patients show higher rates of certain side effects (appetite increase, prolactin elevation, vomiting, blood pressure increases) than adults. (1) (2) (3) (4) (5) (6) (7)

Elderly

Quetiapine is not indicated in elderly patients with dementia because of the boxed-warning mortality risk. Lower starting doses and slower titration are recommended in elderly patients generally, given increased susceptibility to orthostatic hypotension and other effects. (1) (2) (3) (4) (5) (6) (7)

Hepatic_impairment

Lower starting dose (e.g. 25 mg/day) and slower titration recommended given reduced clearance. (1) (2) (3) (4) (5) (6) (7)

Renal_impairment

No specific dose adjustment identified as required based on renal function alone in the sources reviewed, though general caution applies. (1) (2) (3) (4) (5) (6) (7)

Source_ids

US-DAILYMED-SEROQUEL-2026,UK-EMC-SEROQUEL-SMPC-2026,UK-EMC-SEROQUEL-XL-SMPC-2026 (1) (2) (3) (4) (5) (6) (7)

Monitoring

Before starting

  • Baseline weight, blood sugar, and lipid panel
  • Baseline eye examination (cataract risk with chronic use)
  • Complete blood count if pre-existing low white blood cell count or history of leukopenia/neutropenia
  • Cardiac history and QT-risk assessment
  • For bipolar depression use in children/adolescents/young adults: assessment of suicide risk

During treatment

  • Monitoring weight, blood glucose, and lipid levels periodically.
  • Monitoring for movement changes (possible tardive dyskinesia).
  • Monitoring for new or worsening depression or suicidal thoughts, especially in children, adolescents, and young adults being treated for bipolar depression.
  • Monitoring for orthostatic hypotension, falls, and signs of neuroleptic malignant syndrome.
  • Periodic eye examinations (approximately every 6 months) during chronic treatment.
  • Periodic complete blood counts in at-risk patients.
(1) (2)

Storage

Store at room temperature, away from moisture and light, out of reach of children.

Study the drug class: Atypical antipsychotics · Mood stabilisers

Professional information

Clinician-facing context only, sourced from the current US, UK, EU, Canadian, Australian, and New Zealand labels reviewed; verify against the current full label before prescribing, and note the market-specific contraindication and indication-scope differences described above.

United States

Indication: Schizophrenia (adults, adolescents 13-17); bipolar mania (adults, pediatric 10-17); bipolar depression (adults); MDD adjunct (Seroquel XR only, adults)

Dose summary: Schizophrenia: 25 mg BID starting, titrate to 300-400 mg/day by Day 4, range 150-750 mg/day. Bipolar mania: 100 mg Day 1 to 400 mg/day by Day 4, target 400-800 mg/day. Bipolar depression: once daily at bedtime, titrate to 300 mg/day by Day 4. CYP3A4 interactions framed as dose-adjustment caution, not contraindication.

Renal context: No specific renal dose-adjustment requirement identified in the reviewed label. (1)

United Kingdom / European Union

Indication: Schizophrenia; bipolar mania; bipolar depression; recurrence prevention; MDD add-on (Seroquel XL only) -- indications harmonised across the EU via a 2014 Article 30 referral

Dose summary: Similar dose ranges to the US for approved indications; UK/EU CONTRAINDICATE strong CYP3A4 inhibitors and grapefruit juice absolutely, unlike the US dose-caution approach.

Renal context: No specific renal dose-adjustment requirement identified in the reviewed SmPC. (2) (3) (4)

Canada, Australia, New Zealand

Indication: Schizophrenia, bipolar mania, bipolar depression (all three markets); dementia-mortality warning confirmed via Canada's Serious Warnings and Precautions box and Australia's product information (figures matching the US label).

Dose summary: Dosing follows the same core titration principles as the US/UK for each indication.

Renal context: No specific renal dose-adjustment requirement identified in the sources reviewed. (5) (6) (7)

Mechanism of action

Hepatic guidance

Lower starting dose recommended in hepatic impairment given reduced clearance.

Overdose note

No specific antidote. Manage supportively with continuous cardiac monitoring given the QT-prolongation risk reported in overdose; consider gastric lavage and activated charcoal per standard overdose protocols. (1) (2)

Frequently asked questions

Does quetiapine carry a boxed warning?

Yes -- two parts, in fact, on the current US label. The first covers increased mortality in elderly patients with dementia-related psychosis (quetiapine is not approved for this use). The second covers increased risk of suicidal thoughts and behaviour in children, adolescents, and young adults -- this is present because quetiapine itself is used to treat bipolar depression, not because quetiapine is an antidepressant. Health Canada and Australia's TGA both confirm equivalent dementia-mortality warnings, with Australia's figures matching the US label exactly. (1) (5) (6)

Is the major depressive disorder (MDD) adjunct use approved for all quetiapine tablets?

No. The MDD add-on indication applies only to the extended-release product -- Seroquel XR in the United States and Seroquel XL in the United Kingdom. It is not an approved use for the immediate-release Seroquel tablet. (1) (3)

Can I drink grapefruit juice while taking quetiapine?

This is a real difference between markets. In the United Kingdom, grapefruit juice and strong CYP3A4-inhibitor medicines are listed as an ABSOLUTE CONTRAINDICATION with quetiapine. The current US label treats the same interaction as a dose-adjustment caution rather than an outright contraindication. Follow the product information for your own country and your prescriber's specific guidance. (2) (1)

What happens if I stop taking quetiapine suddenly?

Abruptly stopping quetiapine can cause withdrawal symptoms such as insomnia, nausea, and vomiting. If you and your prescriber decide to ask the prescriber about stopping it, it is generally recommended to taper the dose gradually, typically over 1-2 weeks, under your prescriber's guidance -- never stop or change your dose on your own. (2)

What is the mechanism of action of quetiapine fumarate?

Quetiapine's mechanism of action in schizophrenia and bipolar disorder is not fully established, but is thought to be mediated through a combination of dopamine D2 and serotonin 5-HT2A receptor antagonism, along with activity at other serotonergic (5-HT1A), histaminergic (H1), and adrenergic (alpha-1) receptors, contributing to its sedative and metabolic effects. (1) (2)

What is the generic name of Quetiapine?

The generic name is quetiapine fumarate. (1) (2)

What class of drug is quetiapine fumarate?

Quetiapine is classed as: Atypical antipsychotic (dibenzothiazepine derivative). (1) (2)

References

  1. SEROQUEL (quetiapine fumarate) tablets -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information, AstraZeneca / generic manufacturers · United States · accessed 2026-07-31 · source 1
  2. SEROQUEL 25 mg, 100 mg, 200 mg, 300 mg film-coated tablets -- Summary of Product Characteristics (SmPC)electronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-31 · source 2
  3. Seroquel XL prolonged-release tablets (50/150/200/300/400 mg) -- Summary of Product Characteristics (SmPC)electronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-31 · source 3
  4. Questions and answers -- Seroquel, Seroquel XR and associated names (quetiapine) Article 30 referralEuropean Medicines Agency (EMA), Article 30 referral · European Union · accessed 2026-07-31 · source 4
  5. SEROQUEL / SEROQUEL XR (quetiapine fumarate) -- Product MonographHealth Canada / AstraZeneca Canada Inc. and generic manufacturers, Product Monograph · Canada · accessed 2026-07-31 · source 5
  6. SEROQUEL quetiapine (as fumarate) 25mg tablet blister pack (ARTG 58112); SEROQUEL XR 200mg modified release tablet (ARTG 138920)Therapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-31 · source 6
  7. SEROQUEL (quetiapine) -- New Zealand Data SheetMedsafe (New Zealand regulator) -- official New Zealand Data Sheet · New Zealand · accessed 2026-07-31 · source 7

Brand names by country

Single-ingredient quetiapine fumarate names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • SEROQUEL400 mg, 300 mg, 100 mg, 200 mg, 150 mg, 50 mg, 25 mg · h2-pharma, llc

United Kingdom

  • SEROQUEL (2)current licensed product · 25 mg, 100 mg, 200 mg, 300 mg film-coated tablet · See current emc SmPC
  • Seroquel XL (3)current licensed product · 50 mg, 150 mg, 200 mg, 300 mg, 400 mg prolonged-release tablet · See current emc SmPC

Canada

  • QUETIAPINE XR
  • SEROQUEL XR
  • SEROQUEL
  • TEVA-QUETIAPINE XR
  • SANDOZ QUETIAPINE XRT

Australia

  • SEROQUEL (6)current register product · 25 mg tablet · Luye Pharma Australia Pty Ltd
  • SEROQUEL XR (6)current register product · 200 mg modified-release tablet · Luye Pharma Australia Pty Ltd

New Zealand

  • SEROQUEL (7)current registered product · 25 mg, 100 mg, 200 mg, 300 mg tablet · See current Medsafe data sheet
  • Quetapel (7)current registered product · 25 mg, 100 mg, 200 mg, 300 mg tablet · See current Medsafe data sheet
View brands in additional countries.

European Union

Seroquel / Seroquel XR (nationally authorised, harmonised via 2014 EMA Article 30 referral) (4)

This page provides general reference information about quetiapine and is not a substitute for advice from the prescriber managing your treatment. All dosing and treatment decisions should be made with your prescriber, especially given the real market-specific differences in approved uses and contraindications described above.

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