Switching From Twice-Daily to Once-Daily Clozapine Dosing in Schizophrenia

What this study is about

Plasma half-life has routinely been used to establish the dosing schedule of antipsychotics; for example, it is recommended that agents with a short plasma half-life be administered multiple times per day. However, to date, several randomized controlled trials (RCTs) have shown no differences in clinical outcomes between once- and twice-daily dosing of various antipsychotics, suggesting that once-daily dosing of antipsychotics is a viable option regardless of plasma half-life. This would apply to clozapine as well; however, there have been no studies comparing once-daily vs. twice-daily dosing regimens of clozapine in terms of efficacy and tolerability. To address this gap in the literature, the investigators shall conduct a pilot, double-blind, RCT to examine efficacy and tolerability following a switch to once-daily dosing regimen of clozapine in patients with schizophrenia receiving clozapine twice a day.

Who can join (things the study team will check)

✅ You may be able to join if…

• Diagnosed with schizophrenia or schizoaffective disorder based on DSM-IV criteria
• Outpatient status
• Ages 18 years or older
• Has received clozapine twice a day, one of which is in the evening/bedtime, at the same dose and dosing regimen for at least 3 months
• Fluent in English and competent to provide written informed consent

🚫 You may not be able to join if…

• Having significant medical or neurological illnesses
• Pregnant or lactating

Where this trial is running

• Centre for Addiction and Mental Health, Toronto, Ontario, Canada

Who to contact

Gary Remington, MD, PhD · +1-416-535-8501 · Gary.Remington@camh.ca

It's completely normal to call and ask questions before deciding anything. Mention the study ID: NCT02639702.