Carbidopa/Levodopa Combined With Behavioral Therapy for the Treatment of Cocaine Dependence

The University of Texas System (UT)

Status and phase: Completed; Phase 2

Conditions: Cocaine Dependence

Treatments: Behavioral: Contingency Management; Behavioral: Cognitive Behavioral Therapy; Drug: Placebo; Drug: levodopa

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT00713583

DPMCDA

R01DA023608-01 (U.S. NIH Grant/Contract)

1R01DA023608-01 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

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.

Enrollment: 85 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• between 18 and 60 years of age
• meet Diagnostic and Statistical Manual of Mental Disorders, 4th. Edition (DSM-IV) criteria for current cocaine dependence.
• be in acceptable health on the basis of interview, medical history and physical exam.

Exclusion criteria

• current DSM-IV diagnosis of any psychoactive substance dependence other than cocaine, marijuana, or nicotine.
• have a DSM-IV axis I psychiatric disorder or neurological disease or disorder requiring ongoing treatment and/or making study participation unsafe.
• have significant current suicidal or homicidal ideation.
• have medical conditions contraindicating levodopa/carbidopa pharmacotherapy. Conditions include severe pulmonary disease (bronchial asthma, emphysema), cardiovascular disease (severe or history of myocardial infarction with residual arrhythmias), narrow angle glaucoma, melanoma, history of peptic ulcer, renal function impairment.
• taking medications known to have significant drug interactions with levodopa/carbidopa (e.g., monoamine oxidase (MAO) inhibitors, anticonvulsants, haloperidol, phenothiazines, selegiline, anesthetics).
• currently or recently (last 3 months) treated for substance use or another psychiatric condition.
• having conditions of probation or parole requiring reports of drug use to officers of the court.
• impending incarceration.
• pregnant or nursing for female patients.
• inability to read, write, or speak English.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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85 participants in 2 patient groups, including a placebo group

Levodopa pharmacotherapy

Experimental group

Description:

Levodopa pharmacotherapy (800mg levodopa and 200mg carbidopa per day), cognitive behavioral therapy (CBT), and contingency management (CM).

Treatment:

Drug: levodopa

Behavioral: Contingency Management

Behavioral: Cognitive Behavioral Therapy

Placebo

Placebo Comparator group

Description:

Placebo, cognitive behavioral therapy (CBT), and contingency management (CM).

Treatment:

Drug: Placebo

Behavioral: Contingency Management

Behavioral: Cognitive Behavioral Therapy