CompletedNCT00880997Updated Aug 22, 2019Results posted

The Efficacy of Doxazosin for Cocaine Users

A Phase 1 interventional study of Doxazosin and Placebo in Cocaine Dependence, sponsored by Baylor College of Medicine. Completed at 1 site in United States. Open to participants aged 18 Years to 64 Years. Per ClinicalTrials.gov, last updated 2019-08-22.

Sponsored by Baylor College of Medicine · Phase 1, Interventional, and Treatment

Phase: Phase 1
Study type: Interventional
Enrollment: 35
Allocation: Randomized
Ages: 18 Years to 64 Years
Sex: All

Study summary

Doxazosin, an alpha 1-adrenergic receptor, may play an important role in cocaine addiction in humans. This study will evaluate the effectiveness of doxazosin in preventing drug relapse among cocaine dependent participants.

Read the detailed description

The NE system, especially the alpha 1-adrenergic receptor, may play an important role in cocaine addiction in humans. The results of this study will provide medical safety data on the duration of the induction schedule that will be optimal for attaining our target dose of 8 mg doxazosin daily and will guide future pharmacotherapy trials using Doxazosin or related alpha 1 receptor antagonists for cocaine addiction.

This 17-week double-blind, placebo controlled clinical trial includes a 13 week medication trial (weeks 1-13) and up to 4 week washout period(weeks 14-17). Qualifying subjects will be randomized to receive Doxazosin 8 mg/day, or placebo during the study participation.

Medication induction will occur at a rate of 2mg/week until 8mg/day target dose is achieved as follows:

Dox-Fast Group: Defined as participants reaching the target dose after a 4-week titration period. Participants will be stabilized on doxazosin or placebo over weeks 4-13 (for Dox-Fast group)
Dox-Slow Group: Defined as participants reaching the target dose after an 8-week titration period. Participants will be stabilized on doxazosin or placebo over weeks 8-13 (for Dox-Slow group)

Both groups will be tapered off doxazosin or placebo over study weeks 14-17.

Conditions studied

Cocaine Dependence

Browse trials for

Cocaine-Related Disorders 415

Keywords

Cocaine Dependence
Substance Related Disorders

In context

Cocaine-Related Disorders

415 studies on the registry are indexed under Cocaine-Related Disorders; 12 are open to participants now.

This study's enrollment of 35 is below the median of 60 across 312 interventional studies indexed under Cocaine-Related Disorders.

Browse Cocaine-Related Disorders studies →

Lead sponsor

Baylor College of Medicine is the lead sponsor of 734 studies on the registry; 110 are open to participants now.

Of its 83 completed or terminated interventional studies of FDA-regulated products, 44 (53%) have results posted.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 18 Years to 64 Years
Sexes eligible: All
Accepts healthy volunteers: No

Inclusion criteria

Meets DSM-IV diagnosis criteria for cocaine dependence, as determined by self-reported use of cocaine at least once weekly for at least 1 month prior to study entry; a positive urine test for cocaine; and a score greater than 3 on the Severity of Dependence Scale
If female, willing to use contraception throughout the study

Exclusion criteria

Exclusion Criteria:

Meets DSM-IV diagnosis criteria for dependence on any drugs other than cocaine, or tobacco
Current major psychiatric illness, including schizophrenia, bipolar disorder, or other psychotic disorder
Current suicidal or homicidal ideation
Current use of a prescribed psychotropic medication that cannot be discontinued
History of or current major medical illness, including major heart, kidney, endocrine, or liver disorder; abnormal liver function (SGOT or SGPT levels three times greater than normal); or high blood pressure or low blood pressure
High risk factor for heart disease, seizure disorders, or any illness for which disulfiram or methadone treatment would be inadvisable
Currently taking metronidazole or clotrimazole
Pregnant or breastfeeding

Study design

Phase: Phase 1
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel assignment
Masking: Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment: 35 participants (actual)

Study arms

Experimental
Doxazosin
Medication induction occurred at a rate of 2mg/week until 8mg/day target dose was achieved as follows: 1. Dox-Fast Group: Defined as participants reaching the target dose after a 4-week titration period. Participants were stabilized on doxazosin or placebo over weeks 4-13 (for Dox-Fast group) 2. Dox-Slow Group: Defined as participants reaching the target dose after an 8-week titration period. Participants were stabilized on doxazosin or placebo over weeks 8-13 (for Dox-Slow group) Both groups were tapered off doxazosin or placebo over study weeks 14-17.
Drug: Doxazosin
Placebo comparator
placebo
A sugar pill to mimic the experiment drug, doxazosin, will be administered in the same manner as the experimental drug through the study duration.
Other: Placebo

Interventions

DrugDoxazosin
Medication induction occurred at a rate of 2mg/week until 8mg/day target dose was achieved as follows: 1. Dox-Fast Group: Defined as participants reaching the target dose after a 4-week titration period. Participants were stabilized on doxazosin or placebo over weeks 4-13 (for Dox-Fast group) 2. Dox-Slow Group: Defined as participants reaching the target dose after an 8-week titration period. Participants were stabilized on doxazosin or placebo over weeks 8-13 (for Dox-Slow group) Both doxazosin groups will be tapered off doxazosin or placebo over study weeks 14-17.
Also known as: Cardura (Doxazosin Mesylate)
OtherPlacebo
Participants will be administered a sugar pill to mimic the doxazosin active medication with administration being the same as the active medication.
Also known as: sugarpills ( Capsules)

What researchers measure

Primary outcomes

Cocaine Negative Urines
cocaine urine toxicology samples were obtained thrice weekly and tested for the presence of the cocaine metabolite, benzoylecgonine
Time frame: throughout the study - up to 17 weeks

Secondary outcomes

Weeks of Abstinence
Percentage of participants achieving 2 or more consecutive weeks of abstinence
Time frame: throughout the study - up to 17 weeks
# of Participants That Completed the Study
Retention
Time frame: throughout the study - up to 17 weeks
Adverse Events
Time frame: throughout study - upto 17 weeks

Results

Posted Aug 22, 2019

Limitations and caveats

Initially the study randomized subjects into 2 conditions (placebo/DOX). After the observation that rapid titration was safe, a DOX-fast group was created. This did not allow for early participants to be randomized to the rapid titration condition.

Participant flow

Thirty-five subjects were randomized into the study, with 30 subjects returning and receiving at least one dose of medication.

Participant flow — Overall Study
Milestone	Doxazosin Fast	Doxazosin Slow	Placebo
Started	9	8	13
Completed	6	6	5
Not completed	3	2	8

Outcome measures

PrimaryCocaine Negative Urines

cocaine urine toxicology samples were obtained thrice weekly and tested for the presence of the cocaine metabolite, benzoylecgonine

Time frame:: throughout the study - up to 17 weeks
Reported as:: Number · percentage of cocaine-negative urines

Cocaine Negative Urines
percentage of cocaine-negative urines	DOX-slow Group	DOX-fast Group	Placebo
Cocaine Negative Urines	10	35	14

SecondaryWeeks of Abstinence

Percentage of participants achieving 2 or more consecutive weeks of abstinence

Time frame:: throughout the study - up to 17 weeks
Reported as:: Number · percentage of participants

Weeks of Abstinence
percentage of participants	DOX-slow Group	DOX-fast Group	Placebo
Weeks of Abstinence	0	44	7

Secondary# of Participants That Completed the Study

Retention

Time frame:: throughout the study - up to 17 weeks
Reported as:: Count of participants · Participants

# of Participants That Completed the Study
Participants	DOX-slow Group	DOX-fast Group	Placebo
# of Participants That Completed the Study	6	6	5

SecondaryAdverse Events

Time frame:: throughout study - upto 17 weeks
Reported as:: Number · events

Adverse Events
events	DOX-slow Group	DOX-fast Group	Placebo
Adverse Events	26	9	23

Adverse events

Collected over Adverse events were collected over the entire study duration for all patients, up to 17 weeks.. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
Group	Deaths	Serious	Other
Dox-Slow Group	0/8 (0%)	0/8 (0%)	2/8 (25%)
Dox-Fast Group:	0/9 (0%)	0/9 (0%)	3/9 (33.3%)
Placebo	0/13 (0%)	0/13 (0%)	3/13 (23.1%)

Most frequent other events

Most frequent other events
Event	Dox-Slow Group	Dox-Fast Group:	Placebo
HeadachesNervous system disorders	2/8	1/9	3/13
DizinnessCardiac disorders	0/8	2/9	0/13
ToothacheGeneral disorders	1/8	1/9	0/13

Baseline characteristics

Cocaine dependent individuals = 17; Placebo = 13; 5 lost to followup. During analysis, an additional 2 individuals were dropped due from analyses due to invalidated data.

Age, Categorical
Age, Categorical(Participants)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
<=18 years	0	0	0	0
Between 18 and 65 years	8	9	13	30
>=65 years	0	0	0	0

Age, Continuous
Age, Continuous(years)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
Mean	50.1 ± 7.4	47.4 ± 11.0	48.2 ± 8.6	48 ± 9

Sex: Female, Male
Sex: Female, Male(Participants)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
Female	0	2	2	4
Male	8	7	11	26

Race (NIH/OMB)
Race (NIH/OMB)(Participants)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
American Indian or Alaska Native	0	0	0	0
Asian	0	0	0	0
Native Hawaiian or Other Pacific Islander	0	0	0	0
Black or African American	7	3	10	20
White	1	6	3	10
More than one race	0	0	0	0
Unknown or Not Reported	0	0	0	0

Region of Enrollment
Region of Enrollment(participants)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
United States	8	9	13	30

Employment
Employment(Participants)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
Count of participants	6	7	9	22

Alcohol use - past 30 days
Alcohol use - past 30 days(days)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
Mean	6.63 ± 3.77	10.11 ± 9.55	7.85 ± 9.89	8.5 ± 8

Cocaine use - past 30 days
Cocaine use - past 30 days(days)	Doxazosin Slow Titration	Doxazosin Fast Titration	Placebo	Total
Mean	18.13 ± 8.90	7.89 ± 6.92	14.85 ± 10.25	15 ± 8.27

Study locations

1 site

Baylor College of Medicine - Michael E. DeBakey VA Medical Center
Houston, Texas 77030, United States

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Aug 22, 2019, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT00880997
Lead sponsor: Baylor College of Medicine
Collaborators: National Institute on Drug Abuse (NIDA)
Responsible party: Thomas R. Kosten, MD (Professor, Baylor College of Medicine) — Principal investigator
First posted: Apr 14, 2009
Start date: Sep 2009
Primary completion: Apr 2011
Completion: Dec 2011
Results posted: Aug 22, 2019
Last update: Aug 22, 2019

Study contacts

Thomas R Kosten, MD

principal investigator · Baylor College of Medicine

Oversight

Data monitoring committee: Yes

View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Aug 2019. You cannot join it, but the record below documents what was studied.

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