DrugLib.com — Drug Information Portal

Rx drug information, pharmaceutical research, clinical trials, news, and more

Study of the Effect of Dosing on Clozapine Levels

Information source: University of British Columbia
ClinicalTrials.gov processed this data on August 20, 2015
Link to the current ClinicalTrials.gov record.

Condition(s) targeted: Psychotic Disorders; Schizophrenia

Intervention: Clozapine (Drug)

Phase: Phase 4

Status: Not yet recruiting

Sponsored by: University of British Columbia

Official(s) and/or principal investigator(s):
Ric M. Procyshyn, Ph.D, Principal Investigator, Affiliation: University of British Columbia
Alasdair Barr, Ph.D, Study Director, Affiliation: University of British Columbia
William Honer, MD, Study Director, Affiliation: University of British Columbia
Randall White, MD, Study Director, Affiliation: University of British Columbia

Overall contact:
Heidi Boyda, Ph.D, Phone: 604-822-7500, Email: hnboyda@gmail.com


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

Clinical Details

Official title: A Pilot Study to Determine How Frequency of Administration Modifies Steady-State Plasma Concentrations of Orally Administered Clozapine

Study design: Endpoint Classification: Pharmacokinetics Study, Intervention Model: Single Group Assignment, Masking: Open Label

Primary outcome: Change from baseline in steady-state trough plasma concentrations of clozapine and norclozapine at Days 7 and 14.

Secondary outcome:

Change from baseline in symptoms at Day 14.

Change from baseline in side effect burden at Day 14

Changes from baseline in laboratory measures at Day 14.

Change from baseline in weight and waist circumference at Day 14.

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.


Minimum age: 19 Years. Maximum age: 65 Years. Gender(s): Both.


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

Locations and Contacts

Heidi Boyda, Ph.D, Phone: 604-822-7500, Email: hnboyda@gmail.com

UBC Hospital - Detwiller Pavilion, Vancouver, British Columbia V6T 2A1, Canada; Not yet recruiting
Ric M. Procyshyn, Ph.D, Principal Investigator
Alasdair Barr, Ph.D, Sub-Investigator
William Honer, MD, Sub-Investigator
Randall White, MD, Sub-Investigator
Additional Information

Starting date: January 2015
Last updated: November 4, 2014

Page last updated: August 20, 2015

-- advertisement -- The American Red Cross
Home | About Us | Contact Us | Site usage policy | Privacy policy

All Rights reserved - Copyright DrugLib.com, 2006-2017