Efficacy and Tolerability of Clozapine versus Quetiapine in Treatment-resistant Schizophrenia

firemonkey · December 30, 2017, 12:48pm

ncbi.nlm.nih.gov

Efficacy and Tolerability of Clozapine versus Quetiapine in Treatment-resistant Schizophrenia.

M Kumar, BS Chavan, A Sidana and S Das, Indian journal of psychological medicine, Nov-Dec 2017

To compare the efficacy and tolerability of clozapine and quetiapine in patients with treatment-resistant schizophrenia (TRS).In this prospective, randomized, open label study of 14 weeks, 53 patients with schizophrenia diagnosed as per ICD-10 and fulfilling the modified version of Conley and Kelly's criteria of TRS were randomly assigned to receive clozapine or quetiapine as per a computer-generated random table. After 2-weeks of dose-titration phase, doses were fixed at minimum therapeutic dose and subsequently adjusted according to the clinical improvement. All patients received dosage of respective drug in therapeutic range. 13 patients were lost to follow up. Treatment efficacy and side effects were evaluated with standardized rating scales.Clozapine group (reduction in total score: mean=14.45, SD=10.39) had significantly greater reductions (P=0.004; CI=3.541-17.059) in the Positive and Negative Syndrome Scale (PANSS) total score, PANSS positive subscale and PANSS general psychopathology subscale at 14 weeks in comparison to the quetiapine group (reduction in total score: mean=4.15, SD=10.71). Significant reduction in PANSS negative subscale was seen with both drugs but no significant difference was present between the two drugs. At 14 weeks, 30% patients in clozapine group and 15% patients in quetiapine group showed response. Clozapine led to significantly greater side effects (P< 0.001, CI=2.241-6.059) on Glassgow Antipsychotic Side-effect Scale (GASS) than quetiapine.Clozapine was found to be more efficacious than quetiapine in patients with TRS but was associated with greater side effects. Both the drugs were found to be equally effective in reducing the negative symptoms.

anon17132524 · December 30, 2017, 1:07pm

I currently take quetiapine, but I used to take clozapine.

The side-effects of clozapine, particularly drooling, played a significant role in why I switched to quetiapine.

far_cry0 · December 30, 2017, 1:09pm

I take seroquel its doing fine to me …!!! I fear clozapine cause it lowers wbc count…but its a boon for treatment resistance…

anon20318121 · December 30, 2017, 1:28pm

I dont know where i read it but i read that doses of up to 50mg of olanzapine were even better than clozapine.

Im not saying its true but ive just read over it somewhere

firemonkey · December 30, 2017, 1:45pm

ncbi.nlm.nih.gov

The effects of clozapine and high-dose olanzapine on brain function in treatment-resistant schizophrenia: a case study.

RR Conley, DL Kelly, LL Beason-Held, HH Holcomb and CM Richardson, Journal of psychopharmacology (Oxford, England), Sep 2004

Although demonstrating superior efficacy in people with treatment-resistant schizophrenia, clozapine may cause serious side effects, requires blood monitoring and is costly to administer. Olanzapine is similar to clozapine in molecular structure and pharmacologic action but has not demonstrated as robust results as clozapine at routine doses (10-25 mg). Here we present a case study measuring blood flow by positron emission tomography (PET) imaging for a patient treated sequentially with a high dose of olanzapine (50 mg/day) followed by clozapine each for 8 weeks in a double-blind design. During a task, clozapine produced more brain activation patterns than during treatment with olanzapine or during the drug free condition (2 week washout). Clozapine resulted in recruitment of frontal, parietal and cingulate regions that did not appear to be active during olanzapine in this 44 year old right handed male. Additionally, a more robust decrease in symptoms was noted on the Brief Psychiatric Rating Scale (BPRS) score than with olanzapine treatment. These findings suggest that high doses of olanzapine do not produce similar brain activation patterns as clozapine in people with treatment-resistant schizophrenia.

ncbi.nlm.nih.gov

Adverse effects and laboratory parameters of high-dose olanzapine vs. clozapine in treatment-resistant schizophrenia.

DL Kelly, RR Conley, CM Richardson, CA Tamminga and WT Carpenter, Annals of clinical psychiatry : official journal of the American Academy of Clinical Psychiatrists, Sep-Dec 2003

Patients with treatment-resistant schizophrenia pose a major challenge to caregivers since only clozapine is documented as having superior efficacy in this population. Although olanzapine is similar to clozapine in structure and receptor profile, it has not been proven to have superior efficacy for this patient group. Nonetheless, olanzapine is being increasingly used in higher doses as clinicians attempt to find a more effective and tolerable therapy for refractory patients. Furthermore, there are little data comparing olanzapine and clozapine in this population. Thirteen patients participated in a randomized double-blind 16-week crossover study of clozapine therapy (450 mg/day) compared to high doses of olanzapine (50 mg/day). No patients on olanzapine responded while 20% responded to clozapine treatment. Olanzapine patients tended to experience higher rates of anticholinergic effects such as dry mouth (80 vs. 20%) and blurry vision (40 vs. 0%). Clozapine-treated patients had higher rates of sialorrhea (80 vs. 10%), sweating (50 vs. 10%), dyspepsia (70 vs. 30%), and lethargy (90 vs. 60%). Neither treatment was associated with significant akathisia. Liver enzyme elevation and lipids were higher with clozapine treatment. Mean weight gain in the initial 8 weeks was 3.4 kg for olanzapine and 1.2 kg for clozapine. High doses of olanzapine during 8 weeks of treatment did not increase lipids and liver enzymes like clozapine did. Olanzapine at 50 mg/day may be associated with more anticholinergic effects and weight gain than clozapine.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1557475/

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Efficacy and Tolerability of Clozapine versus Quetiapine in Treatment-resistant Schizophrenia

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