Switch medication from Clozapine to Quetiapine.
- Day 1: Decrease daily dose with 25 mg every 2 days
- 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
- 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.
- During this switch you could monitor ECG, especially in patients prone to QT-conduction problems.
- There is a possibility of QT interval prolongation.
- KNMP; Informatorium Medicamentorum 2015; Monografie "quetiapine" (Dutch)
- NVZA; Toxicology.org; Monografie 73 (dutch)
- Woods SW Chlorpromazine equivalent doses for the newer atypical antipsychotics J Clin Psychiatry 2003;64:663-667
- Drugs.com quetiapine-fumarate
- 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.
- 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.
- Agid O, Kapur S, Remington G, Emerging drugs for schizophrenia. Expert Opin Emerg Drugs. 2008 Sep;13(3):479-95.
- Stöllberger C, Huber JO, Finsterer J, Antipsychotic drugs and QT prolongation. Int Clin Psychopharmacol. 2005 Sep;20(5):243-51.
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