Quetiapine

Antipsychotic Drug

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.