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Study of the Effect of Dosing on Clozapine Levels (PK-CLZ)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02286206
Recruitment Status : Unknown
Verified November 2017 by Ric Procyshyn, University of British Columbia.
Recruitment status was:  Active, not recruiting
First Posted : November 7, 2014
Last Update Posted : November 29, 2017
Information provided by (Responsible Party):
Ric Procyshyn, University of British Columbia

Brief Summary:

The objectives of this 15-day study are:

  1. To compare steady-state trough plasma concentrations of clozapine and its metabolite norclozapine when given once daily and twice daily (at the same total daily dose)
  2. To determine if frequency of clozapine administration has an effect on:

    1. Symptoms of schizophrenia
    2. Adverse effects of clozapine
    3. Fasting blood glucose, lipids, creatinine, and urea
    4. Weight and waist circumference

Condition or disease Intervention/treatment Phase
Psychotic Disorders Schizophrenia Drug: Clozapine Phase 4

Detailed Description:
It is important that clinicians do everything possible to optimize the use of clozapine in individuals with treatment-resistant schizophrenia. To our knowledge, there are no published studies evaluating whether twice daily administration of clozapine is better than once daily administration in terms of effectiveness and tolerability. Although this may seem trivial at first, when we consider that clozapine has a relatively short half-life and dissociates quickly from the dopamine D2 receptor, it justifies further consideration. It takes on even more significance knowing that the established threshold clozapine plasma concentration for therapeutic response (i.e., 350-420 ng/ml) was determined using steady-state trough plasma samples (i.e., approximately 12 hours after the evening dose) in patients administered clozapine twice rather than once daily.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 50 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: A Pilot Study to Determine How Frequency of Administration Modifies Steady-State Plasma Concentrations of Orally Administered Clozapine
Study Start Date : January 2015
Estimated Primary Completion Date : December 2017
Estimated Study Completion Date : December 2017

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Schizophrenia
Drug Information available for: Clozapine

Arm Intervention/treatment
Experimental: Clozapine bid

Participants have been taking clozapine once daily and have reached steady-state prior to the start of this study.

Intervention: Days 1-14

Drug: Clozapine
One-half baseline dose po bid (or one-third baseline dose po qam and two-thirds baseline dose po qhs at the discretion of the treating clinicians and principal investigator)
Other Names:
  • Clozaril
  • FazaClo

Primary Outcome Measures :
  1. Change from baseline in steady-state trough plasma concentrations of clozapine and norclozapine at Days 7 and 14. [ Time Frame: Days 0 (baseline), 7, and 14 ]
    Steady-state trough plasma concentrations of clozapine and norclozapine will be measured on Days 7 and 14 and compared to those obtained on Day 0 (baseline).

Secondary Outcome Measures :
  1. Change from baseline in symptoms at Day 14. [ Time Frame: Day 0 (baseline) and 14 ]
    As assessed by structured clinical interviews for the Positive and Negative Syndrome Scale (PANSS)

  2. Change from baseline in side effect burden at Day 14 [ Time Frame: Days 0 (baseline) and 14 ]
    As assessed by the Udvalg for Kliniske Undersøgelser (UKU) Side Effect Rating Scale

  3. Changes from baseline in laboratory measures at Day 14. [ Time Frame: Days 0 (baseline) and 14 ]
    Laboratory measures include fasting blood glucose, fasting lipid profile, creatinine, and urea.

  4. Change from baseline in weight and waist circumference at Day 14. [ Time Frame: Days 0 (baseline) and 14 ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   19 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Participants must be between the ages of 19 - 65
  • Participants must be fluent in English
  • Participants must have a psychiatric diagnosis and are currently treated with clozapine once daily in the evening
  • Participants must be on a stable dose of clozapine for at least one week to ensure steady-state has been achieved

Exclusion Criteria:

  • Participants who are hypersensitive to clozapine
  • Participants who are pregnant or lactating
  • Participants who are of childbearing age and not using reliable contraception
  • Participants who have postsurgical complications of the gastrointestinal tract that might impair absorption
  • Participants who have any clinically relevant abnormalities of laboratory parameters
  • Participants who have had a potent CYP1A2 metabolic inducer (e.g., carbamazepine; rifampin) or inhibitor (e.g., amiodarone; cimetidine; efavirenz; fluoroquinolone antibiotics; ticlopidine) added to and/or removed from their medication regimen in the past two weeks

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02286206

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Canada, British Columbia
UBC Hospital - Detwiller Pavilion
Vancouver, British Columbia, Canada, V6T 2A1
Sponsors and Collaborators
University of British Columbia
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Principal Investigator: Ric M. Procyshyn, Ph.D University of British Columbia
Study Director: Alasdair Barr, Ph.D University of British Columbia
Study Director: William Honer, MD University of British Columbia
Study Director: Randall White, MD University of British Columbia
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Responsible Party: Ric Procyshyn, Principle Investigator, University of British Columbia Identifier: NCT02286206    
Other Study ID Numbers: H14-01644
First Posted: November 7, 2014    Key Record Dates
Last Update Posted: November 29, 2017
Last Verified: November 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Keywords provided by Ric Procyshyn, University of British Columbia:
Psychotropic Drugs
Antipsychotic Agents
Psychotic Disorders
Adverse Effects
Drug Monitoring
Additional relevant MeSH terms:
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Mental Disorders
Psychotic Disorders
Schizophrenia Spectrum and Other Psychotic Disorders
Serotonin Antagonists
Serotonin Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Antipsychotic Agents
Tranquilizing Agents
Central Nervous System Depressants
Psychotropic Drugs
GABA Antagonists
GABA Agents