Quetiapine
Drug class: Atypical antipsychotic
Quetiapine (SEROQUEL)（中文：喹硫平）
Pronunciation
Quetiapine 25mg (SEROQUEL 25mg)
Quetiapine fumarate extended-release 200mg (SEROQUEL XR 200mg)
Quetiapine fumarate extended-release 50mg (SEROQUEL XR 50mg)
Common Strengths of Quetiapine Tablet
Quetiapine tablets are available in the following strengths:
- 25 mg, 50 mg, 100 mg, 200 mg, 300 mg, 400 mg tablets
Drug Trade Names of Amisulpride Tablet
Seroquel, Seroquel XR
Drug Usage
Quetiapine is used for:
- Treatment of schizophrenia
- Acute treatment of manic episodes associated with bipolar disorder
- Acute treatment of depressive episodes associated with bipolar disorder
- Maintenance treatment of bipolar I disorder as adjunct therapy to lithium
- Adjunctive treatment of major depressive disorder (MDD)
Mechanism of Action
Quetiapine is an antagonist at multiple neurotransmitter receptors in the brain, including serotonin 5-HT1A and 5-HT2, dopamine D1 and D2, histamine H1, and adrenergic α1
and α2 receptors.
Route of Administration
- Oral (tablets and oral solution)
Dosages
- Schizophrenia: 150-750 mg/day
- Bipolar mania: 400-800 mg/day
- Bipolar depression: 300-600 mg/day
- Major depressive disorder (adjunct): 150-300 mg/day
No dosage adjustment is necessary for patients with renal impairment. It is metabolized primarily in the liver, and renal function does not affect its pharmacokinetics
significantly.
Side Effects
| Frequency | Adverse reactions |
|---|---|
| Common | Dizziness: Often occurs when standing up quickly. It is advisable to stand up slowly to mitigate this effect |
| drowsiness: can affect daily activities such as driving or operating machinery | |
| Dizziness | |
| Dry mouth: Staying hydrated and using sugar-free gum or candy can help alleviate dry mouth | |
| Weight gain and increased appetite: Patients may experience significant weight gain | |
| Less common | Blurred Vision |
| Stomach Pain and Upset Stomach: Including nausea and vomiting | |
| Fatigue and Weakness: General feelings of tiredness and lack of energy[6][8] | |
| Increased Blood Sugar Levels: This can lead to or worsen diabetes | |
| Uncontrolled Muscle Movements: Such as tremors, jerking, or stiffness, which could indicate tardive dyskinesia | |
| Neuroleptic Malignant Syndrome (NMS): Symptoms include high fever, muscle stiffness, confusion, and sweating. This is a medical emergency | |
| QT Prolongation: A heart rhythm condition that can lead to serious (and sometimes fatal) irregular heartbeats | |
| Severe Allergic Reactions: Signs include hives, difficulty breathing, and swelling of the face, lips, tongue, or throat | |
| Infections: Increased susceptibility to infections due to lowered white blood cell counts | |
| Suicidal Thoughts: Especially in younger patients or those with a history of depression |
Pharmacokinetics
- Absorption
- Rapidly absorbed with peak plasma concentrations occurring approximately 1.5 hours post-dose
- Metabolism
- Extensively metabolized in the liver primarily via CYP3A4.
- Elimination
- Mean terminal half-life is approximately 6 hours
The onset of action may be seen within 1-2 weeks, with full effects typically observed within 4-6 weeks.
Drug Precautions
Pregnancy
- Use with caution; potential risks to the fetus should be considered
Breastfeeding
- CNot recommended; quetiapine is excreted in human milk
Children & Elderly
- Not approved for use in children under 10 years old; use with caution in elderly patients
Temperature regulation
- Quetiapine can interfere with your body's ability to regulate temperature. Avoid overheating and dehydration, especially during exercise or in hot weather.
Suicidal thoughts
- Monitor for worsening depression or suicidal thoughts, especially in young adults and children.
Do not stop taking quetiapine suddenly without consulting your doctor. The dose may need to be tapered slowly.
Monitoring Requirements
- Weight, blood glucose, lipid profile, signs of extrapyramidal symptoms
Drug Interactions
- YP3A4 Inducers and Inhibitors: Drugs that induce CYP3A4 (e.g., phenytoin, thioridazine) can increase the clearance of quetiapine, while inhibitors (e.g., ketoconazole) can
decrease its clearance, necessitating dosage adjustments.
- caution with drugs that prolong QT interval
FAQ
How Should I Take the Tablet?
- Take quetiapine usually once or twice daily with or without food.
What should I avoid while taking?
- Avoid alcohol and activities requiring mental alertness until you know how quetiapine affects you.
- Avoid eating grapefruit or drinking grapefruit juice while taking quetiapine.
What Happens if I Miss a Dose?
- Take the missed dose as soon as you remember unless it is almost time for your next dose. Do not double doses.
