What is quetiapine (atypical antipsychotic)?

From the Guidelines

Quetiapine is an atypical antipsychotic medication that should be used with caution due to its potential for serious side effects, particularly in older adults and those with a history of medical conditions, as it can worsen cognitive function in dementia and increase the risk of metabolic side effects 1.

Overview of Quetiapine

Quetiapine is primarily used to treat schizophrenia, bipolar disorder, and as an add-on treatment for major depressive disorder. It works by balancing certain neurotransmitters in the brain, particularly dopamine and serotonin, which helps control symptoms like hallucinations, delusions, mood swings, and depression.

Dosage and Administration

Quetiapine is available in immediate-release tablets (typically dosed 2-3 times daily) and extended-release formulations (taken once daily), with dosages ranging from 25mg to 800mg depending on the condition being treated.

Side Effects and Monitoring

Common side effects include drowsiness, dizziness, dry mouth, weight gain, and increased blood sugar levels. The medication often causes sedation, so it's typically taken at bedtime, especially when starting treatment. Patients should be aware that quetiapine requires gradual dose adjustments under medical supervision, and should not be stopped abruptly as this can cause withdrawal symptoms. Regular monitoring of metabolic parameters (weight, blood sugar, lipids) is important during treatment due to potential metabolic side effects, as noted in studies such as 1 and 1.

Special Considerations

In the context of older adults, quetiapine is considered one of the atypical antipsychotics that should be used with caution due to its sedating properties and potential to worsen cognitive function in dementia, as highlighted in 1.

Clinical Use

Despite these considerations, quetiapine has been found to be effective in treating various psychiatric conditions, including schizophrenia and bipolar disorder, as discussed in studies such as 1 and 1. However, its use should always be carefully evaluated against the potential risks, particularly in vulnerable populations.

From the FDA Drug Label

Quetiapine is a psychotropic agent belonging to a chemical class, the dibenzothiazepine derivatives. The chemical designation is 2-[2-(4-dibenzo [b,f ] 1, 4thiazepin-11-yl-1-piperazinyl)ethoxy]-ethanol fumarate (2:1) (salt). Quetiapine is a psychotropic agent belonging to the dibenzothiazepine derivatives class. It is used as an antipsychotic medication. Key points about quetiapine include:

• Chemical designation: 2-[2-(4-dibenzo [b,f ] 1, 4thiazepin-11-yl-1-piperazinyl)ethoxy]-ethanol fumarate (2:1) (salt)
• Molecular formula: C42H50N6O4S2•C4H4O4
• Molecular weight: 883.11 (fumarate salt) 2

From the Research

Definition and Mechanism of Quetiapine

• Quetiapine is an orally administered atypical antipsychotic indicated for the treatment of schizophrenia and bipolar disorder, including bipolar depression 3.
• It is an antagonist at both serotonin 5-HT2 and dopamine D2 receptors, and its antipsychotic effects are thought to stem from interactions at these receptors 3.
• The antidepressant effects of quetiapine are poorly understood, but may be related to antagonism of 5-HT2A receptors in cortical regions, partial agonism of 5-HT1A in the prefrontal cortex, or to reduced synaptic reuptake of noradrenaline resulting from inhibition of the noradrenaline reuptake transporter by the quetiapine metabolite norquetiapine 3.

Efficacy and Tolerability

• Quetiapine has been shown to be effective in the treatment of bipolar depression, with significant improvements in depressive symptoms and global severity of illness scores compared to placebo 3.
• It is generally well tolerated, with most treatment-emergent adverse events being of mild to moderate severity, including dry mouth, sedation, somnolence, dizziness, and constipation 3.
• Quetiapine has also been compared to typical antipsychotics, with results suggesting that it may cause fewer adverse effects, less abnormal ECG, fewer extrapyramidal effects, and less weight gain 4.

Comparison to Other Antipsychotics

• Quetiapine has been compared to olanzapine in the treatment of negative symptoms in patients with schizophrenia, with both treatments showing similar efficacy and tolerability 5.
• It has also been compared to risperidone and olanzapine, with results suggesting that quetiapine may be a valuable addition to the first-line treatments for bipolar depression 3.
• A review of 43 randomized controlled trials found that quetiapine may not differ from typical antipsychotics in the treatment of positive symptoms and general psychopathology, but may cause fewer adverse effects 4.

Use in Specific Populations

• Quetiapine has been used to treat elderly patients with psychotic disorders, with results suggesting that it may be a safe and effective medication for this population 6.
• It has also been used to treat patients with treatment-refractory schizophrenia, with results suggesting that it may be effective in reducing symptoms and improving quality of life 7.