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Quetiapine Stats & Data

Depressant

Derin Seroquel Xeroquel Ketilept Ketipinor

NPS DataHub

MW383.51

FormulaC21H25N3O2S

CAS111974-69-7

IUPAC2-(2-(4-Dibenzo[''b'',''f''][1,4]thiazepine-11-yl-1-piperazinyl)ethoxy)ethanol

SMILESOCCOCCN1CCN(CC1)C1=Nc2ccccc2Sc2ccccc12

InChIKeyURKOMYMAXPYINW-UHFFFAOYSA-N

Psychoactive Class Depressant

Half-Life 6-7 hours (immediate release); 7-12 hours (extended release)

Pharmacology

DrugBank

State Solid

Description

Initially approved by the FDA in 1997, quetiapine is a second-generation atypical antipsychotic used in schizophrenia, major depression, and bipolar disorder. Quetiapine demonstrates a high level of therapeutic efficacy and low risk of adverse effects during long-term treatment. It is well-tolerated and a suitable option for some patients with high sensitivity to other drugs, such as Clozapine and Olanzapine.

Mechanism of Action

Although the mechanism of action of quetiapine is not fully understood, several proposed mechanisms exist. In schizophrenia, its actions could occur from the antagonism of dopamine type 2 (D2) and serotonin 2A (5HT2A) receptors. In bipolar depression and major depression, quetiapine's actions may be attributed to the binding of this drug or its metabolite to the norepinephrine transporter. Additional effects of quetiapine, including somnolence, orthostatic hypotension, and anticholinergic effects, may result from the antagonism of H1 receptors, adrenergic α1 receptors, and muscarinic M1 receptors, respectively.

Pharmacodynamics

Quetiapine improves the positive and negative symptoms of schizophrenia and major depression by acting on various neurotransmitter receptors, such as the serotonin and dopamine receptors. In bipolar disorder, it improves both depressive and manic symptoms. **A note on suicidality in young patients and administration in the elderly** Quetiapine can cause suicidal thinking or behavior in children and adolescents and should not be given to children under 10 years of age. It is important to monitor for suicidality if this drug is given to younger patients. In addition, this drug is not indicated for the treatment of psychosis related to dementia due to an increased death rate in elderly patients taking this drug.

Metabolism

The metabolism of quetiapine occurs mainly in the liver. Sulfoxidation and oxidation are the main metabolic pathways of this drug. According to in vitro studies, cytochrome P450 3A4 metabolizes quetiapine to an inactive sulfoxide metabolite and also participates in the metabolism of its active metabolite, N-desalkyl quetiapine. CYP2D6 also regulates the metabolism of quetiapine. In one study, three metabolites of N-desalkylquetiapine were identified. Two of the metabolites were identified as N-desalkylquetiapine sulfoxide and 7-hydroxy-N-desalkylquetiapine. CYP2D6 has been found to be responsible for metabolism of quetiapine to 7-hydroxy-N-desalkylquetiapine, a pharmacologically active metabolite. Individual differences in CYP2D6 metabolism may be present, which may affect the concentrations of the active metabolite.

Absorption

Quetiapine is rapidly and well absorbed after administration of an oral dose. Steady-state is achieved within 48 hours Peak plasma concentrations are achieved within 1.5 hours. The bioavailability of a tablet is 100%. The steady-state Cmax of quetiapine in Han Chinese patients with schizophrenia after a 300 mg oral dose of the extended released formulation was approximately 467 ng/mL and the AUC at steady-state was 5094 ng·h/mL. Absorption of quetiapine is affected by food, with Cmax increased by 25% and AUC increased by 15%.

Toxicity

The oral LD50 if quetiapine in rats is 2000 mg/kg. **Overdose information** Some signs and symptoms of a quetiapine overdose include sedation, drowsiness, tachycardia, and hypotension. Clinical trials demonstrate that overdoses of up to 30 grams of quetiapine did not result in death. A lethal outcome was reported in a clinical trial after an overdose of 13.6 grams of quetiapine. In the case of an acute overdose, ensure to maintain an airway and provide adequate ventilation and oxygenation. Gastric lavage following intubation (if necessary) along with activated charcoal and a laxative may be considered. The possibility of obtundation, seizure or dystonic reaction of the head and neck following overdose may create a risk of aspiration with induced emesis. Cardiac monitoring should also take place. **A note on QT-interval prolongation in an overdose** Postmarketing reports reveal increases in the cardiac QT interval in cases of quetiapine overdose, concomitant illness, and in those taking drugs that increase QT interval or affect electrolyte levels. Note that disopyramide, procainamide, and quinidine may exert additive QT-prolonging effects when administered in patients who have overdosed with quetiapine, and should be avoided.

Indication

Quetiapine is used in the symptomatic treatment of schizophrenia. In addition, it may be used for the management of acute manic or mixed episodes in patients with bipolar I disorder, as a monotherapy or combined with other drugs. It may be used to manage depressive episodes in bipolar disorder. In addition to the above indications, quetiapine is used in combination with antidepressant drugs for the treatment of major depression. Some off-label uses for this drug include the management of post-traumatic stress disorder (PTSD), generalized anxiety disorder, and psychosis associated with Parkinson's disease.

Half-life

The average terminal half-life of quetiapine is about 6-7 hours.

Protein Binding

The protein binding of quetiapine is 83%.

Elimination

After an oral dose of radiolabeled quetiapine, less than 1% of unchanged drug was detected in the urine, suggesting that quetiapine is heavily metabolized. About 73% of a dose was detected in the urine, and about 20% in the feces.

Volume of Distribution

Quetiapine distributes throughout body tissues. The apparent volume of distribution of this drug is about 10±4 L/kg.

Clearance

The clearance of quetiapine healthy volunteers in the fasted state during a clinical study was 101.04±39.11 L/h. Elderly patients may require lower doses of quetiapine, as clearance in these patients may be reduced by up to 50%. Those with liver dysfunction may also require lower doses.

Receptor Profile

Receptor Actions

Agonists

5-HT1A receptor agonist (partial, via norquetiapine metabolite)

Antagonists

5-HT2A receptor antagonist

Dopamine D2 receptor antagonist (low affinity, rapid dissociation)

H1 histamine receptor antagonist

Alpha-1 adrenergic receptor antagonist

Muscarinic acetylcholine receptor antagonist (weak)

Inhibitors

Norepinephrine transporter inhibitor (via norquetiapine metabolite)

Receptor Binding

5-hydroxytryptamine receptor 2A antagonist

D(2) dopamine receptor antagonist

5-hydroxytryptamine receptor 1A antagonist

5-hydroxytryptamine receptor 6 antagonist

D(1A) dopamine receptor antagonist

Histamine H1 receptor antagonist

Alpha-1 adrenergic receptors antagonist

Alpha-2A adrenergic receptor antagonist

Alpha-2B adrenergic receptor antagonist

Alpha-2C adrenergic receptor antagonist

Muscarinic acetylcholine receptor M1 antagonist

Muscarinic acetylcholine receptor M3 antagonist

History & Culture

1985–1997

Quetiapine was developed by the pharmaceutical company AstraZeneca during the mid-1980s through the 1990s as part of efforts to improve upon first-generation antipsychotic medications. The compound received approval from the U.S. Food and Drug Administration in September 1997 and was subsequently marketed under the brand name Seroquel. Within a decade of its initial approval, quetiapine had received regulatory authorization in over 80 countries worldwide.

2007–2023

Quetiapine quickly became one of the most commercially successful psychiatric medications globally. By 2007, it was among the ten top-selling drugs worldwide alongside other second-generation antipsychotics. Annual sales reached approximately $5.7 billion globally, with roughly half of that revenue coming from the United States market alone. The original U.S. patent was set to expire in 2011 but received a pediatric exclusivity extension that pushed expiration to March 2012. Following patent expiration, generic formulations became widely available. Despite increased competition from generics, quetiapine remained the most frequently prescribed second-generation antipsychotic in the United States by 2013, with over 14 million prescriptions dispensed that year. As of 2023, it ranked as the 65th most commonly prescribed medication in the country with more than 10 million annual prescriptions.

2010–present

In 2010, AstraZeneca agreed to pay a $520 million settlement to resolve allegations of improper marketing practices and mishandling of clinical trial data. Internal company communications revealed that the manufacturer had suppressed and misrepresented research findings showing quetiapine lacked superior efficacy compared to older first-generation antipsychotic medications. Similar concealment occurred with studies demonstrating significant risks of obesity and weight gain. The company also reportedly resisted requests from the FDA to inform prescribing physicians about diabetes risks that were greater than previously acknowledged.

While recreational use remains relatively uncommon compared to other psychoactive substances, reports of quetiapine misuse have emerged in medical literature. This pattern appears driven primarily by the drug's sedative and anxiolytic properties rather than its antipsychotic effects, with individuals seeking it for sleep induction or general calming. Non-medical use has been particularly noted within correctional settings. Some estimates suggest that a substantial proportion of inmates presenting with psychiatric complaints in certain facilities may be attempting to obtain quetiapine through feigned symptoms. The prevalence of misuse in prisons compared to community settings is attributed to quetiapine's availability as a regularly prescribed sedative within these institutions, combined with the general unavailability of more commonly sought substances behind bars.

Subjective Effect Notes

physical: The physical effects of quetiapine can be broken down into several components which progressively intensify proportional to dosage.

cognitive: The general head space of quetiapine is often described as one of sleepiness, emptiness, apathy, stupor and catatonia. The specific cognitive effects can be broken down into several components which progressively intensify proportional to dosage.

Tolerance & Pharmacokinetics

drugs.wiki

Half-Life

6-7 hours (immediate release); 7-12 hours (extended release)

Addiction Potential

Low; not considered habit-forming, but misuse for sedative effects has been reported.

Experience Report Analysis

Erowid

127 Reports

2000–2024 Date Range

55 With Age Data

30 Effects Detected

Demographics

Gender Distribution

Age Distribution

Reports Over Time

Effect Analysis

Erowid

Effects aggregated from 127 experience reports (127 Erowid)

127 Reports

30 Effects Detected

12 Positive

11 Adverse

7 Neutral

Effect Sentiment Distribution

Confidence Distribution

Positive Effects 12

Stimulation 43.3% 70%

Anxiety Suppression 41.7% 70%

Sedation 40.9% 70%

Euphoria 17.3% 70%

Empathy 14.2% 70%

Color Enhancement 13.4% 70%

Focus Enhancement 11.0% 70%

Tactile Enhancement 9.4% 70%

Music Enhancement 9.4% 70%

Introspection 5.5% 70%

Creativity Enhancement 3.1% 70%

Body High 3.1% 70%

Adverse Effects 11

Confusion 21.3% 70%

Psychosis 18.9% 70%

Memory Suppression 10.2% 70%

Motor Impairment 7.9% 70%

Nausea 7.1% 70%

Seizure 5.5% 70%

Headache 3.9% 70%

Muscle Tension 3.9% 70%

Pupil Dilation 3.9% 70%

Sweating 3.1% 70%

Increased Heart Rate 2.4% 70%

Dose-Response Correlation

How effect frequency changes across dose levels

View data table

Effect	Light (n=15)	Common (n=23)	Strong (n=17)	Heavy (n=18)
Sedation	40.0%	39.1%	64.7%	33.3%
Stimulation	60.0%	34.8%	47.1%	16.7%
Anxiety Suppression	46.7%	34.8%	47.1%	33.3%
Psychosis	13.3%	30.4%	0%	33.3%
Euphoria	13.3%	21.7%	29.4%	0%
Color Enhancement	13.3%	8.7%	29.4%	16.7%
Empathy	26.7%	13.0%	0%	0%
Hospital	13.3%	26.1%	11.8%	22.2%
Auditory Effects	20.0%	13.0%	23.5%	16.7%
Confusion	20.0%	17.4%	23.5%	11.1%
Visual Distortions	20.0%	13.0%	23.5%	16.7%
Focus Enhancement	20.0%	0%	23.5%	0%
Introspection	13.3%	0%	0%	0%
Dissociation	13.3%	0%	11.8%	0%
Seizure	13.3%	0%	0%	11.1%

Dose–Effect Mapping

Experience Reports

How reported effects shift across dose tiers, based on 127 experience reports.

Oral dose range: 50.0–300.0 mg (median 100.0 mg)

Effect	Light (n=15)	Common (n=23)	Strong (n=17)	Heavy (n=18)
sedation	40%	39%	65%	33%	↓
stimulation	60%	35%	47%	17%	↓
anxiety suppression	47%	35%	47%	33%	↓
psychosis	13%	30%	—	33%	↑
euphoria	13%	22%	29%	—	↑
color enhancement	13%	9%	29%	17%	↑
empathy	27%	13%	—	—	↓
hospital	13%	26%	12%	22%	↑
auditory effects	20%	13%	24%	17%	↓
confusion	20%	17%	24%	11%	↓
visual distortions	20%	13%	24%	17%	↓
focus enhancement	20%	—	24%	—	↑
introspection	13%	—	—	—	→
dissociation	13%	—	12%	—	→
seizure	13%	—	—	11%	↓
memory suppression	13%	—	12%	—	→
tactile enhancement	—	—	12%	11%	→
nausea	—	—	12%	—	→
muscle tension	—	—	12%	—	→
body high	—	—	12%	—	→

Showing top 20 of 22 effects

Risk Escalation

Sentiment Analysis

Average frequency of positive vs adverse effects across dose tiers

Light n=15

6 positive 24.4% 5 adverse 21.3%

Common n=23

4 positive 19.6% 3 adverse 27.5%

Strong n=17

6 positive 25.5% 6 adverse 19.6%

Heavy n=18

4 positive 13.9% 5 adverse 20.0%

View effect breakdown

Adverse Effects

Effect	Light (n=15)	Common (n=23)	Strong (n=17)	Heavy (n=18)	Change
Anxiety Suppression	47%	35%	47%	33%	-28%
Psychosis	13%	30%	—	33%	+150%
Confusion	20%	17%	24%	11%	-44%
Seizure	13%	—	—	11%	-16%
Memory Suppression	13%	—	12%	—	-11%
Nausea	—	—	12%	—	0%
Muscle Tension	—	—	12%	—	0%
Motor Impairment	—	—	12%	11%	-5%

Positive Effects

Effect	Light (n=15)	Common (n=23)	Strong (n=17)	Heavy (n=18)	Change
Stimulation	60%	35%	47%	17%	-72%
Euphoria	13%	22%	29%	—	+121%
Color Enhancement	13%	9%	29%	17%	+25%
Empathy	27%	13%	—	—	-51%
Focus Enhancement	20%	—	24%	—	+17%
Introspection	13%	—	—	—	0%
Tactile Enhancement	—	—	12%	11%	-5%
Body High	—	—	12%	—	0%
Music Enhancement	—	—	—	11%	0%

Dosage Distribution

Dose distribution from experience reports

Median: 100.0 mg IQR: 50.0–300.0 mg n=73

Real-World Dose Distribution

62K Doses

From 200 individual dose entries

Oral (n=177)

Median: 100.0mg 25th: 50.0mg 75th: 200.0mg 90th: 400.0mg

mg/kg median: 1.336 mg/kg 75th: 3.149

Common Combinations

Most co-occurring substances in experience reports

Form / Preparation

Most common forms and preparations reported

Body-Weight Dosing

Dose relative to body weight from reports with weight data

Median: 1.576 mg/kg IQR: 0.543–3.799 mg/kg n=71

Redose Patterns

Redosing behavior across 99 reports

4.0% Redosed

1.1 Avg Doses

180m Median Interval

Read full reports on Erowid →

Legal Status

Country	Status	Notes
Australia	Prescription Only	Regulated as a prescription-only medicine. Not scheduled as a prohibited or controlled substance but restricted to medical dispensing.
Austria	Prescription Only	Available exclusively through prescription. Not scheduled as a controlled substance under Austrian drug laws but regulated as a prescription pharmaceutical.
Canada	Prescription Only	Available by prescription only. Multiple branded and generic formulations are marketed in Canada, with the original patent having expired.
France	Prescription Only	Unscheduled as a controlled substance but legally restricted to prescription-only status under French pharmaceutical regulations.
Germany	Prescription Only (Anlage 1 AMVV)	Regulated as a prescription medicine under Anlage 1 of the Arzneimittelverschreibungsverordnung (AMVV), the German regulation governing prescription requirements for medicinal products.
Switzerland	Abgabekategorie B (Prescription Only)	Classified under Abgabekategorie B in the Swiss pharmaceutical dispensing system, meaning it can only be dispensed with a valid medical prescription.
United Kingdom	Prescription Only	Available only by prescription. The substance is not scheduled under the Misuse of Drugs Act but regulated as a prescription-only medicine under pharmaceutical legislation.
United States	Unscheduled (Prescription Only)	Quetiapine is not a scheduled controlled substance but requires a prescription for legal sale and distribution. FDA approved the drug in 1997. Possession without a prescription is not criminalized, though sales and distribution are restricted to licensed entities and require valid prescriptions.

Harm Reduction