Quetiapine

Generic Name: Quetiapine
Common Brand Names: Seroquel

Introduction

Quetiapine is an atypical antipsychotic used to treat various psychiatric conditions, including schizophrenia, bipolar disorder, and major depressive disorder as an adjunctive treatment.

Conditions of Use (Indications)

1. Schizophrenia: Used to manage symptoms of schizophrenia, including delusions, hallucinations, and cognitive disturbances.
2. Bipolar Disorder: Used in the acute treatment of manic episodes and maintenance therapy to prevent mood swings in bipolar disorder.
3. Major Depressive Disorder: As an adjunct to antidepressants in treatment-resistant depression.

Mechanism of Action

Quetiapine works by antagonizing various neurotransmitter receptors in the brain, primarily serotonin (5HT2) and dopamine (D2) receptors. Its action on serotonin receptors is believed to contribute to its mood-stabilizing properties, while its D2 antagonism helps alleviate psychotic symptoms. Quetiapine’s sedative properties are attributed to its antagonism of histamine receptors.

Side Effects

1. Common:

• Sedation or drowsiness.
• Weight gain, increased appetite.
• Dry mouth and constipation.

2. Serious:

• Extrapyramidal symptoms (e.g., tremors, rigidity).
• Metabolic changes, including elevated blood sugar, cholesterol, and triglycerides.
• Risk of tardive dyskinesia (long-term use).

Harmful Interactions

1. CNS Depressants: Concurrent use with other sedative medications (e.g., benzodiazepines, alcohol) may exacerbate sedation and respiratory depression.
2. Antihypertensive Agents: Quetiapine can lower blood pressure, so caution is needed when used with antihypertensive drugs.
3. CYP3A4 Inhibitors: Drugs like ketoconazole and clarithromycin can increase quetiapine levels, leading to side effects.

Contraindications

1. Known hypersensitivity to quetiapine or other components of the formulation.
2. Patients with a history of arrhythmias or significant cardiovascular disease.
3. Use in the elderly with dementia-related psychosis is contraindicated due to increased risk of mortality.

Latest References

1. De Hert, M., et al. (2023). “Quetiapine in the Treatment of Bipolar Disorder and Schizophrenia.” Psychopharmacology, DOI: 10.1007/s00213-023-06171-3.
2. American Psychiatric Association (APA). (2022). “Schizophrenia and Bipolar Disorder Treatment Guidelines.” APA Guidelines.