Addition of Ondansetron to Ongoing Antipsychotic Treatment for Schizophrenia
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ClinicalTrials.gov Identifier: NCT00149734 |
Recruitment Status :
Completed
First Posted : September 8, 2005
Results First Posted : August 13, 2021
Last Update Posted : August 13, 2021
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Condition or disease | Intervention/treatment | Phase |
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Schizophrenia | Drug: Ondansetron followed by placebo Drug: Placebo followed by Ondansetron | Phase 3 |
Schizophrenia is a devastating brain disorder. Most people with schizophrenia have difficulty filtering out unimportant auditory information. They have an inability to appropriately inhibit, or gate, sensory information that enters the ear. Standard treatments do not address this problem. When the drug ondansetron is taken in addition to typical antipsychotic drugs, P50 auditory gating improves. However, ondansetron has not been used with some of the newer, atypical antipsychotic drugs. This study will evaluate the effect of combining ondansetron with newer, atypical antipsychotic drugs on P50 auditory gating.
Participants in this double-blind study will be randomly assigned to receive either ondansetron or placebo for 3 months. Upon completion of the first 3 months, participants will be crossed over to receive the other treatment for an additional 3 months. All participants will also take an atypical antipsychotic drug, including olanzapine, quetiapine, or aripiprazole. Auditory gating will be assessed using computerized cognitive testing and functional magnetic resonance imaging (fMRI) at baseline and Months 3 and 6. Vital signs and evoked potentials will be assessed at Weeks 1, 3, and 6. Clinical symptoms and cognitive abilities will also be evaluated to determine the effectiveness of ondansetron.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 8 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | Atypical Antipsychotics and P50 Sensory Gating |
Study Start Date : | January 2005 |
Actual Primary Completion Date : | May 2010 |
Actual Study Completion Date : | May 2010 |

Arm | Intervention/treatment |
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Experimental: Ondansetron followed by placebo
Participants will take ondansetron then placebo plus an atypical antipsychotic drug
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Drug: Ondansetron followed by placebo
Participants will take 16mg of ondansetron daily for the first three months followed by 3 months of placebo. An atypical antipsychotic drug (olanzapine,quetiapine, or aripiprazole) will also be taken throughout the 6 months treatment period.
Other Name: Zofran, Zuplenz |
Experimental: Placebo followed by Ondansetron
Participants will take placebo then ondansetron plus an atypical antipsychotic drug
|
Drug: Placebo followed by Ondansetron
Participants will take placebo daily for the first three months followed by 3 months of 16mg of ondansetron daily. An atypical antipsychotic drug (olanzapine,quetiapine, or aripiprazole) will also be taken throughout the 6 months treatment period.
Other Name: Zofran, Zuplenz |
- P50 Sensory Gating [ Time Frame: Up to 3 hours ]P50 Sensory Gating as measured by evoked potentials (response to stimuli, in this case, clicking sounds).The P50 potential was identified and measured using a computer algorithm. The amplitude of the P50 test wave was divided by the amplitude of the P50 conditioning wave, expressed as a percentage: the P50 ratio. Lower P50 ratios represent better outcomes.
- Cognitive Testing [ Time Frame: Measured at Months 3 and 6 ]

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Ages Eligible for Study: | 18 Years to 55 Years (Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Meets DSM-IV criteria for schizophrenia
- Stable, chronic schizophrenia
- Currently taking atypical medications
- Use of effective form of contraception throughout study
Exclusion Criteria:
- History of any alcohol or drug abuse within 3 months of study start date
- Any other major neurological disorders
- History of or current head trauma
- Any medical conditions affecting the central nervous system
- Current epilepsy, asthma, migraine headache, previous myocardial infarction, stroke, diabetes, hypertension, narrow angle glaucoma, or neuromuscular illnesses
- Pregnant

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 ClinicalTrials.gov identifier (NCT number): NCT00149734
United States, Colorado | |
Denver VAMC | |
Denver, Colorado, United States, 80220 |
Principal Investigator: | Lawrence E. Adler, MD | University of Colorado Health Sciences Center, VISN19 MIRECC |
Responsible Party: | University of Colorado, Denver |
ClinicalTrials.gov Identifier: | NCT00149734 |
Other Study ID Numbers: |
04-0255 R01MH050787 ( U.S. NIH Grant/Contract ) COMIRB # 04-0255 DNBBS 73-MCR |
First Posted: | September 8, 2005 Key Record Dates |
Results First Posted: | August 13, 2021 |
Last Update Posted: | August 13, 2021 |
Last Verified: | July 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Product Manufactured in and Exported from the U.S.: | No |
Schizophrenia Ondansetron P50 sensory gating |
Evoked potentials 5-HT3 receptors Atypical antipsychotics |
Schizophrenia Schizophrenia Spectrum and Other Psychotic Disorders Mental Disorders Ondansetron Antiemetics Autonomic Agents Peripheral Nervous System Agents Physiological Effects of Drugs Gastrointestinal Agents Antipruritics |
Dermatologic Agents Serotonin Antagonists Serotonin Agents Neurotransmitter Agents Molecular Mechanisms of Pharmacological Action Antipsychotic Agents Tranquilizing Agents Central Nervous System Depressants Psychotropic Drugs Anti-Anxiety Agents |