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Clozapine-Quetiapine

Clozapine
Type Antipsychotic
Group Atypical AP
links
Medscape Clozapine
PubChem 2818
PubMed Clozapine
Kompas (Dutch) Clozapine
Wikipedia Clozapine
Quetiapine
Type antipsychotic
Group atypical AP
Other use moodstabilizer
links
ATC-code N05AH04
Medscape Quetiapine
PubChem 5002
PubMed Quetiapine
Drugs.com quetiapine-fumarate
Kompas (Dutch) Quetiapine
Wikipedia Quetiapine

Switch medication from Clozapine to Quetiapine.[5] [6]

Nietinrijdenbord.png Stop Clozapine
  • Day 1: Decrease daily dose with 25 mg every 2 days
Eenrichtingbord.png Start Quetiapine
  • Week 1: approx. 25% of target dose
  • Week 2: approx. 50% of target dose
  • Week 3: approx. 75% of target dose
  • Week 4: target dose
Infobord.png More information
  • Clozapine is generally considered to be more effective than other antipsychotic drugs. Clozapine is often used in treatment-resistant schizophrenia (poor treatment response to 2 or more antipsychotic drugs). So a switch from clozapine to another antipsychotic drug could cause problems regarding effectiveness.[7] [8] [9]
  • During this switch you could monitor ECG, especially in patients prone to QT-conduction problems.
  • There is a possibility of QT interval prolongation.[10]
    StartStandDownClozapine.jpg
Nietinrijdenbord.png — Clozapine
Eenrichtingbord.png — Quetiapine


  1. 1.0 1.1 1.2 KNMP; Informatorium Medicamentorum 2023; Monografie "quetiapine" (Dutch)
  2. NVZA; Toxicology.org; Monografie 73 (dutch)
  3. Woods SW Chlorpromazine equivalent doses for the newer atypical antipsychotics J Clin Psychiatry 2003;64:663-667
  4. Drugs.com quetiapine-fumarate
  5. Switches are based on literature references on this page and expert opinions of the authors. The authors have used pharmacokinetic and receptor affinity properties to determine the switch schedules
  6. Stahl, S. M. (2013). Stahl's essential psychopharmacology: Neuroscientific basis and practical applications (4th ed.). Cambridge University Press.
  7. McEvoy J P et al., Effectiveness of clozapine versus olanzapine, quetiapine, and risperidone in patients with chronic schizophrenia who did not respond to prior atypical antipsychotic treatment. Am J Psychiatry. 2006;163:600–610.
  8. Lewis S W et al., Randomized Controlled Trial of Effect of Prescription of Clozapine Versus Other Second-Generation Antipsychotic Drugs in Resistant Schizophrenia. Schizophrenia Bulletin vol.32 no.4 pp.715–723,2006.
  9. Agid O, Kapur S, Remington G, Emerging drugs for schizophrenia. Expert Opin Emerg Drugs. 2008 Sep;13(3):479-95.
  10. Stöllberger C, Huber JO, Finsterer J, Antipsychotic drugs and QT prolongation. Int Clin Psychopharmacol. 2005 Sep;20(5):243-51.
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