Quetiapine, Seroquel®

Brand name

  • Seroquel®

Drug Class

  • Antipsychotic


  • Tablets: 25, 50, 100, 200, 300, and 400 mg


  • Schizophrenia
  • Bipolar disorder


  • Although the mechanism of action of quetiapine is unknown,
  • Likely to it inhibits communication between nerves by blocking receptors
  • Blocks the dopamine type 2 (D2) and serotonin type 2 (5-HT2) receptors
  • Can be taken with or without food


  • Quetiapine is eliminated from the body by liver enzyme cytochrome P450


  • Bipolar disorder:
    • 100 mg to 400 mg/d
    • Most patients respond to 400-800 mg/d
  • Schizophrenia:
    • 25 mg twice daily (50 mg/d)
    • can be increased by 25-50 mg two or three times daily
    • The target dose: 300-400 mg/d in two or three doses
  • Best response at doses of 150-750 mg/d

Drug Interactions

  • Drugs that decrease quetiapine’s effect:
    • Phenytoin (Dilantin)
    • thioridazine (Mellaril)
  • Quetiapine can increase the sedating effects of drugs such as:
    • oxycodone,
    • acetaminophen,
    • barbiturates,
    • alprazolam (Xanax)
    • clonazepam (Klonopin),
    • ethanol
    • prazosin (Minipress)
    • Terazosin (Hytrin)
  • Drugs that strongly interfere with the enzyme may cause elevated and toxic levels of quetiapine:
    • Ketoconazole (Nizoral)
    • Itraconazole (Sporanox)
    • Fluconazole (Diflucan)
    • Erythromycin
    • Clarithromycin (Biaxin)
    • Nefazodone (Serzone)
    • Verapamil (Calan, Isoptin, Verelan)
    • Diltiazem (Cardizem, Tiazac, Dilacor)

Adverse Effects

  • Hypotension
  • Hyperglycemia
  • DM
  • Drowsiness
  • Fall
  • Poor body temperature control
  • Dizziness
  • Lightheadedness
  • fainting

Pregnancy and Breastfeeding

  • Use in pregnancy if you feels that it is absolutely necessary and that the potential benefits justify the unknown risks to patient


  • Care provider should be aware of the following special events:
    • History of allergic to quetiapine, any other medications
    • Use of any prescription and nonprescription medications, vitamins, nutritional supplements and herbal products such as:
      • Antidepressants
      • Antifungals such as fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend)
      • Antihistamines
      • Barbiturates such as phenobarbital
      • Carbamazepine (Tegretol)
      • Divalproex (Depakote)
      • Dopamine agonists such as bromocriptine (Parlodel), cabergoline (Dostinex), levodopa (Dopar, Larodopa) pergolide (Permax), and ropinirole (Requip)
      • Erythromycin
      • Levodopa (in Parcopa, in Sinemet, in Stalevo)
      • Anxiolytics
    • Having following conditions:
      • High blood pressure
      • Irritable bowel disease,
      • Mental illness
      • Motion sickness
      • Parkinson’s disease
      • Urinary problems
      • Medications for human immunodeficiency virus (HIV)
      • History of diabetes in the patient or their families
      • Use of street drugs
      • Overuse of prescription medications,
      • Dehydration
      • Seizure
      • Cataracts
      • Low number of WBC
      • High cholesterol
      • Hypertension
      • Hypotension
      • History of MI
      • History of stroke
      • Breast cancer
      • Thyroid disorders
      • Heart or liver disease.
      • Pregnancy
      • Breastfeeding
      • Having surgery, including dental surgery
    • Remember to avoid Seroquel if you are:
      • Driving a car or operating machinery
      • Drinking alcohol
      • Doing excessive exercise


This document is prepared by the “Mental Health for All” team. This document is provided for information purposes only and does not necessarily represent endorsement by or an official position of the Essentials of Medicine. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient’s medical history.


  • http://www.medicinenet.com/script/main/hp.asp
  • http://www.nlm.nih.gov/medlineplus/druginfo/meds/a698019.html
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