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[Pharmacology](https://durgical.com/en/pharmacology/) · [Second-generation antipsychotics](https://durgical.com/en/pharmacology/classes/second-generation-antipsychotics/)

# Quetiapine

A sedating atypical antipsychotic for schizophrenia and for both manic and depressive phases of bipolar disorder; few movement effects.

Updated 2026-11-01

- Class: [Second-generation antipsychotics](https://durgical.com/en/pharmacology/classes/second-generation-antipsychotics/)
- Receptor: Dopamine D2 receptor
- ATC code: N05AH04
- WHO Model List of Essential Medicines

◎**Dopamine D2 receptor**Quetiapine

ⓘ The figure shows risperidone in the human D2 receptor; quetiapine binds the same site loosely (no quetiapine-bound D2 structure exists).

**Target in 3D:** Dopamine D2 receptor. PDB structure 6CM4 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6CM4) · Drag to rotate · pinch to zoom

## Mechanism of action

Quetiapine blocks D2 receptors weakly and briefly and 5-HT2A receptors more strongly, with strong H1 and α1 blockade. Weak D2 binding means few extrapyramidal effects and little prolactin rise; H1 and α1 blockade give sedation and orthostatic hypotension.

- Quetiapine weakly blocks D2 and blocks 5-HT2A
- Psychotic, manic and bipolar depressive symptoms improve
- Strong H1 and α1 block: sedation and dizziness on standing

## Pharmacokinetics

**Absorption**
Taken by mouth (immediate- and extended-release tablets)

**Metabolism**
Liver, mainly CYP3A4: strong inhibitors raise its levels and inducers (phenytoin, carbamazepine, rifampicin) lower them markedly

## Indications

- Schizophrenia
- Manic episodes of bipolar I disorder
- Depressive episodes of bipolar disorder
- Maintenance in bipolar I disorder, with lithium or valproate

## Adverse effects

### Common

- Sedation
- Dizziness and orthostatic hypotension
- Dry mouth and constipation
- Weight gain

### Serious (rare, important)

- Suicidal thoughts in young people (boxed warning, as for antidepressants)
- Hyperglycaemia and dyslipidaemia
- QT prolongation in people at risk
- Lens changes (cataracts) with long-term use
- Lower thyroid hormone levels
- Neuroleptic malignant syndrome
- Higher mortality in older people with dementia-related psychosis (boxed warning)

## Contraindications

- Hypersensitivity to quetiapine

## Key interactions

**Ketoconazole and other strong CYP3A4 inhibitors**
Much higher quetiapine levels

**Phenytoin, carbamazepine and other strong CYP3A4 inducers**
Much lower levels and loss of effect

**Other QT-prolonging drugs**
Additive QT prolongation

## What is monitored

- Weight, glucose and lipids
- Mood and suicidal thoughts, especially in young people
- Blood pressure lying and standing
- Eye (lens) examination with long-term use
- Thyroid function

## Administration and safety

- Immediate- and extended-release tablets are different products and are not substituted for each other
- Look-alike names: quetiapine and olanzapine are both antipsychotics with similar names

## Nursing care

- Checks lying and standing blood pressure and helps the patient stand up slowly (orthostatic hypotension, falls)
- Watches for worsening mood or suicidal thoughts and teaches the family to report them
- Records weight, waist, glucose and lipids at baseline and during treatment
- Teaches the patient to avoid overheating and dehydration, and to avoid alcohol and other sedatives

## Pregnancy and breastfeeding

Newborns exposed in the third trimester may have extrapyramidal or withdrawal symptoms (agitation, abnormal tone, tremor, feeding problems); use weighs benefit and risk.

## Memory aid

Quetiapine is the «quiet» one: strong sedation, quiet striatum (few movement effects).

## Test yourself

Think of the answer, then tap the question to see it.

## Why does quetiapine cause few extrapyramidal effects?

It binds D2 receptors weakly and briefly, so striatal D2 occupancy stays low.

## Why does quetiapine carry a suicidality warning like antidepressants?

It is approved for bipolar depression, and antidepressant treatment raised suicidal thoughts in children, adolescents and young adults.

## Which enzyme interactions change quetiapine levels the most?

CYP3A4: strong inhibitors (ketoconazole) raise them; strong inducers (phenytoin, carbamazepine) lower them.

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## Related drugs

- [Olanzapine](https://durgical.com/en/pharmacology/olanzapine/)
- [Clozapine](https://durgical.com/en/pharmacology/clozapine/)

[← Back to the class: Second-generation antipsychotics](https://durgical.com/en/pharmacology/classes/second-generation-antipsychotics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - QUETIAPINE FUMARATE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d51c5bf6-950d-493b-be55-de575c5ef2e7) (DailyMed (U.S. National Library of Medicine), 2026); [Quetiapine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a698019.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/?query=quetiapine) (World Health Organization, 2025); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 19 (McGraw Hill, 2023).

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Representative model, for educational purposes only.

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