Quetiapine
A sedating second-generation antipsychotic used for schizophrenia and for both mania and depression in bipolar disorder.
Drug card
- How it works
- Blocking dopamine D2 and serotonin 5-HT2A receptors
- Used for
- Schizophrenia
- Bipolar disorder: mania, depression and maintenance
- Severe depression, as add-on treatment (UK)
- Known for
- Drowsiness
- Dizziness on standing (orthostatic hypotension)
- Its name
- -apine means an atypical antipsychotic (clozapine type)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does quetiapine work?
Quetiapine, a dibenzothiazepine, binds H1 and α1 receptors most tightly, then 5-HT2A, and D2 only weakly; its active metabolite norquetiapine binds most of these more strongly. Combined D2 and 5-HT2 blockade is thought to underlie its effect, but the mechanism is unclear.
Like other second-generation antipsychotics: Most second-generation antipsychotics block dopamine D2 receptors together with serotonin 5-HT2A receptors, though exactly how they work is unclear; aripiprazole instead is a partial agonist at D2 receptors. As a group they cause fewer extrapyramidal effects than first-generation drugs, but many also block H1, α1 or muscarinic receptors, and weight gain with raised glucose and lipids is common.
Uses
What is quetiapine used for?
- Schizophrenia
- Bipolar disorder: mania, depression and maintenance
- Severe depression, as add-on treatment (UK)
Side effects
Side effects of quetiapine
- DrowsinessKnown for
- Dizziness on standing (orthostatic hypotension)Known for
- Dry mouth
- Constipation
- Weight gain
- Raised blood sugar and lipids (metabolic changes)Serious
- Fast heartbeat
- Cataracts with long-term use
- Lower thyroid hormone levels
- QT prolongationSerious
- Suicidal thoughts in young people treated for depressionSerious
- Insomnia, nausea and vomiting if stopped abruptly
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Check glucose, lipids and weight, and examine the eye lenses at the start and every 6 months for cataracts.
- When used for bipolar depression, monitor young people closely for worsening mood or suicidal thoughts.
- Avoid with other QT-prolonging drugs and in people with QT risk factors.
- Reduce the dose gradually rather than stopping suddenly.
Good to know: Its strongest binding is to H1 and α1 receptors rather than D2, and it is licensed for bipolar depression as well as mania; its label asks for regular lens checks.
Remember it
A way to remember it
Atypicals: fewer shakes, more cakes.
As a group they cause fewer extrapyramidal movement effects than first-generation antipsychotics, but more weight gain and raised glucose and lipids, so weight and blood tests are checked.
Written for biofideX
Its name
-apine means atypical antipsychotic (clozapine type)
Clozapine, olanzapine and quetiapine share it. Mirtazapine, an antidepressant, also ends in -apine, and carbamazepine in -zepine: both come from WHO's broader stem -pine.
- Every drug name stem
Its class
Second-generation antipsychotics
Other second-generation antipsychotics with a card:
Easily mixed up with first-generation antipsychotics and lithium.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Psychosis, mood and ADHD
Quetiapine is one of 9 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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