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Clinical Trial of Dipyridamole in Schizophrenia

This study has been completed.
Information provided by (Responsible Party):
Human Research Protections Office, University of Maryland Identifier:
First received: July 5, 2006
Last updated: January 11, 2013
Last verified: January 2013
This is a 6-week, randomized, double blind, parallel groups designed, olanzapine-controlled trial of oral dipyridamole in symptomatic patients with a (DSM IV) diagnosis of schizophrenia, schizoaffective or schizophreniform disorder. This pilot study aims to provide preliminary estimates of whether the effect sizes of dipyridamole on positive symptoms, negative symptoms, and cognitive deficits differ between schizophrenia patients treated with dipyridamole, and schizophrenia patients treated with olanzapine. A total of 30 subjects will be recruited locally.

Condition Intervention
Schizoaffective Disorder
Schizophreniform Disorder
Drug: Dipyridamole
Other: Olanzapine

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator)
Primary Purpose: Treatment
Official Title: Clinical Trial of Dipyridamole in Schizophrenia

Resource links provided by NLM:

Further study details as provided by University of Maryland:

Primary Outcome Measures:
  • To provide preliminary estimates of effect sizes of dipyridamole on positive symptoms, negative symptoms, and cognitive deficits differ between schizophrenia patients treating with dipyridamole, and schizophrenia patients treated with olanzapine. [ Time Frame: 6 weeks ]

Secondary Outcome Measures:
  • To determine if dipyridamole, a clinically available adenosine agonist, has efficacy for treating positive and negative symptoms and cognitive deficits of schizophrenia. [ Time Frame: 6 weeks ]

Enrollment: 29
Study Start Date: May 2001
Study Completion Date: September 2011
Primary Completion Date: September 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
Drug: Dipyridamole
Week 1- 50 mg bid Week 2- 50 mg am and 100 mg pm Weeks 3-6 100 mg am and 100 mg pm
Active Comparator: 2
Other: Olanzapine
Week 1- 5 mg BID Week 2- 5 mg am and 10 mg pm Weeks 3-6 10 mg am and 10 mg pm

Detailed Description:
Since the demonstrated success of chlorpromazine in treating psychosis in the1950's, the pharmacotherapy of schizophrenia has focused mainly on drugs with antidopaminergic actions. These drugs have robust effects on reality distortion and disorganization symptom complexes, but minimal effect on cognitive impairment, negative symptoms, and functional outcome and quality of life measures. Newer generation antipsychotic drugs have a similar profile of effects, with some advantages on the course of depression, hostility, suicide, hospital readmission rates and motor side effect measures. Side effects such as weight gain, increase in cardiovascular stress and diabetes risk are associated with some new generation drugs. A new class of drugs is needed to address the inadequate effectiveness and the side-effect disadvantages of the currently available pharmacological agents for the treatment of schizophrenia. Recently, new treatment strategies using nicotinergic drugs or agonists at the glycine modulatory site of the glutamatergic N-methyl-D-aspartate (NMDA) receptor have been employed in clinical trials with mixed results. Our proposal focuses on a clinically available adenosine agonist, dipyridamole, in a 6-week clinical trial. Published data suggest effectiveness of dipyridamole in treating psychosis when added to haloperidol treatment. The effectiveness of dipyridamole alone in treating schizophrenia symptoms, although indirectly suggested by several lines of evidence, has not been tested.

Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Subjects between ages 18-65, both males and nonpregnant females (on birth control) Diagnosis of schizophrenia, schizoaffective or schizophreniform disorder Ability to give written informed consent Total BPRS score > 27 Psychosis subscale scores > 7

Exclusion Criteria:

  • Patients with coagulative disorders, bleeding diathesis or currently on anticoagulants, and patients with major medical illnesses (including hypertension, angina, and cardiovascular diseases) or an abnormal baseline ECG.

Patients with moderate to severe mental retardation.

Inability to sign informed consent.

Patients with a history of serious violence (e.g., suicide attempts, or assaultive behavior).

Patients on clozapine treatment within the 6 weeks leading to the double-blind phase.

Patients with a history of olanzapine non-response

Positive Urine Toxicology Screen

  Contacts and Locations
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Please refer to this study by its identifier: NCT00349973

United States, Maryland
Maryland Psychiatric Research Center
Baltimore, Maryland, United States, 21228
Sponsors and Collaborators
University of Maryland
Study Director: Ikwunga Wonodi, MD Maryland Pschiatric Research Center, University of Maryland School of Medicine
Principal Investigator: Gunvant K Thaker, MD University of Maryland
  More Information

Additional Information:
Responsible Party: Human Research Protections Office, Associate Professor, University of Maryland Identifier: NCT00349973     History of Changes
Other Study ID Numbers: HP-00043347
Study First Received: July 5, 2006
Last Updated: January 11, 2013

Keywords provided by University of Maryland:
Positive symptoms
Negative symptoms
Cognitive deficits

Additional relevant MeSH terms:
Schizophrenia Spectrum and Other Psychotic Disorders
Psychotic Disorders
Pathologic Processes
Mental Disorders
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Gastrointestinal Agents
Antipsychotic Agents
Tranquilizing Agents
Central Nervous System Depressants
Psychotropic Drugs
Serotonin Uptake Inhibitors
Neurotransmitter Uptake Inhibitors
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Neurotransmitter Agents
Serotonin Agents
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Platelet Aggregation Inhibitors
Vasodilator Agents processed this record on April 21, 2017