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OpenTrials
Completed

NCT Number: NCT07262736

Pharmacokinetics of Clozapine and Norclozapine and the Effect of Pantoprazole

Clozapine is an effective treatment for patients with schizophrenia who do not respond to other therapies, but its blood concentration varies widely between individuals due to genetic and physiological differences. Proton pump inhibitors such as pantoprazole are often prescribed in this population to prevent stomach discomfort, yet their impact on clozapine exposure has not been fully characterized. This clinical study will investigate the pharmacokinetics of clozapine and its main metabolite norclozapine, the influence of individual characteristics on drug exposure, and the effect of pantoprazole coadministration. Healthy adult volunteers will participate in a randomized open label cross over design, receiving a single dose of clozapine alone and again after pantoprazole treatment. Outcomes include clozapine and norclozapine plasma concentration time profiles, pharmacokinetic parameters, and safety assessments.

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Key information

Conditions

Healthy Volunteers - Male and Female

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

Pusat Sejahtera (Kesihatan & Pergigian)

Pulau Pinang, 11800, Malaysia

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy adult volunteers aged 18 to 50 years
  • No history of chronic medical or psychiatric disease, as confirmed by baseline medical evaluation, medical history, and electrocardiogram (ECG)
  • No use of any medications for at least two weeks before study initiation

Exclusion criteria

  • Pregnant or breastfeeding women
  • Current smokers

Treatment and study plan

Clozapine

Drug

Single dose of 12.5 mg clozapine (half 25 mg tablet)

Pantoprazole

Drug

Five daily doses of pantoprazole tablets 40 mg to be started four days prior to the clozapine administration

Primary outcomes

  1. Peak Plasma Concentration (Cmax)

    Time frame: From pre-dose to 8 hours after a single oral dose of clozapine

    Maximum plasma concentration of clozapine following a single oral dose

  2. Area Under the Plasma Concentration-Time Curve (AUC)

    Time frame: From pre-dose to 8 hours after dosing

    AUC of clozapine plasma concentration from time zero to the last measurable concentration following a single oral dose

Secondary outcomes

  1. Area Under the Concentration-Time Curve Extrapolated to Infinity (AUCinf)

    Time frame: From pre-dose to last measurable concentration

    Area under the plasma concentration-time curve from time zero extrapolated to infinity

  2. Time to Peak Concentration (Tmax)

    Time frame: From pre-dose to 8 hours after dosing

    Time to reach maximum observed plasma concentration of clozapine

Sponsors and collaborators

Lead sponsor

Universiti Sains Malaysia

Other

Registry information

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Dec 4, 2025
Registry last updated
Dec 4, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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