A Phase 2 interventional study of levodopa and Placebo in Cocaine Dependence, sponsored by The University of Texas Health Science Center, Houston. Completed at 1 site in United States. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2018-04-23.
Sponsored by The University of Texas Health Science Center, Houston · Phase 2, Interventional, and Treatment
Cocaine dependence is a major public health problem and the development of a treatment for this disorder is a priority. To date, treatment interventions based on positive incentive principles have shown the strongest effects for improving substance use outcomes. One such example is contingency management (CM) interventions in which nondrug rewards are used to compete with cocaine. Recent evidence suggests that certain medications improve response to CM interventions, particularly agents that target dopamine reward systems in the brain. A promising dopamine-enhancing medication is levodopa. The study team has observed the strongest effects of levodopa when the medication is administered in the context of CM therapy, perhaps through mechanisms that enhance reward saliency. The proposed study is designed to further evaluate this promising treatment approach. Cocaine dependent outpatients will participate in a randomized, 2-group (levodopa vs. placebo), double-blind clinical trial. CM will be behavioral therapy platform for both treatment groups. The study will test the primary hypothesis that CM+levodopa will be more effective than CM+placebo in reducing cocaine use. This study is expected to validate the usefulness of a new behavioral-pharmacological treatment approach for cocaine dependence.
415 studies on the registry are indexed under Cocaine-Related Disorders; 12 are open to participants now.
This study's enrollment of 85 is above the median of 60 across 312 interventional studies indexed under Cocaine-Related Disorders.
Browse Cocaine-Related Disorders studies →The University of Texas Health Science Center, Houston is the lead sponsor of 880 studies on the registry; 209 are open to participants now.
Of its 170 completed or terminated interventional studies of FDA-regulated products, 140 (82%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Levodopa pharmacotherapy (800mg levodopa and 200mg carbidopa per day), cognitive behavioral therapy (CBT), and contingency management (CM).
Drug: levodopa · Behavioral: Cognitive Behavioral Therapy · Behavioral: Contingency Management
Placebo, cognitive behavioral therapy (CBT), and contingency management (CM).
Drug: Placebo · Behavioral: Cognitive Behavioral Therapy · Behavioral: Contingency Management
800mg levodopa and 200mg carbidopa per day
Also known as: Sinemet
Placebo
Participants received individual cognitive behavioral therapy (CBT) in 50-minute weekly sessions. These sessions were manual-driven and based on the relapse prevention model proposed by Marlatt and Gordon (1985). Trained masters-level therapists, under the supervision of senior therapists and the principal investigator, worked with participants to teach them how to recognize and cope with risky situations that could influence their cocaine use through self-monitoring of situational craving and drug use stimuli, coping skills training, and lifestyle modifications.
An abstinence-based contingency management (CM) procedure was used. Participants earned vouchers according to the reward schedule recommended by Budney and Higgins (1998), beginning at $2.50 for the first cocaine-negative urine. For each consecutive cocaine-negative urine, voucher values increased by $1.25 with a $10 bonus given for provision of three consecutive cocaine-negative urines within a week. A cocaine-positive urine or failure to provide a scheduled urine sample resulted in a reset of the schedule to the initial value of $2.50. After provision of five negative urines, the voucher returned to the value prior to the reset. Participants were able to redeem their vouchers for small amounts of cash (≤$25) or gift cards for goods and services.
Confirmed Abstinence From Cocaine as Assessed by Treatment Effectiveness Score (TES)
The Treatment Effectiveness Score (TES) is the number of cocaine-negative urines collected out of the total scheduled urine tests for the 12-week trial (36 total scheduled urine tests per participant). The mean number of cocaine-negative urines over all time points is reported in this outcome measure.
Time frame: 12 weeks of treatment
| Milestone | Levodopa Pharmacotherapy | Placebo |
|---|---|---|
| Started | 45 | 40 |
| Completed | 45 | 40 |
| Not completed | 0 | 0 |
The Treatment Effectiveness Score (TES) is the number of cocaine-negative urines collected out of the total scheduled urine tests for the 12-week trial (36 total scheduled urine tests per participant). The mean number of cocaine-negative urines over all time points is reported in this outcome measure.
| cocaine-negative urines | Levodopa Pharmacotherapy | Placebo |
|---|---|---|
| Confirmed Abstinence From Cocaine as Assessed by Treatment Effectiveness Score (TES) | 7 ± 11.7 | 9 ± 12.6 |
Collected over 12 weeks. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Levodopa Pharmacotherapy | — | 6/45 (13.3%) | 0/45 (0%) |
| Placebo | — | 3/40 (7.5%) | 0/40 (0%) |
| Event | Levodopa Pharmacotherapy | Placebo |
|---|---|---|
| Suicide ideationPsychiatric disorders | 0/45 | 1/40 |
| abscessInfections and infestations | 0/45 | 1/40 |
| Pulmonary embolismVascular disorders | 0/45 | 1/40 |
| Stomach painGastrointestinal disorders | 1/45 | 0/40 |
| DepressionPsychiatric disorders | 1/45 | 0/40 |
| PhotosensitivityEye disorders | 1/45 | 0/40 |
| Head injuryGeneral disorders | 1/45 | 0/40 |
| Transient inability to speakGeneral disorders | 1/45 | 0/40 |
| Blood clotVascular disorders | 1/45 | 0/40 |
| Age, Continuous(years) | Levodopa Pharmacotherapy | Placebo | Total |
|---|---|---|---|
| Mean | 46 ± 7.9 | 45 ± 9.2 | 46 ± 8.5 |
| Sex: Female, Male(Participants) | Levodopa Pharmacotherapy | Placebo | Total |
|---|---|---|---|
| Female | 10 | 5 | 15 |
| Male | 35 | 35 | 70 |
| Region of Enrollment(Participants) | Levodopa Pharmacotherapy | Placebo | Total |
|---|---|---|---|
| United States | 45 | 40 | 85 |
This study is completed, as verified in Mar 2018. You cannot join it, but the record below documents what was studied.
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The University of Texas Health Science Center, Houston