Medications for Stopping Cocaine Dependence and Preventing Relapse

Cocaine is a strong central nervous system stimulant that is widely abused throughout the
United Sates. Due to its widespread use, it is important to develop an effective treatment
for cocaine dependence. Motivational Interviewing (MI) is often effective when combined with
drug treatment. Baseline condition (e.g., abstinence status) and population type (e.g.,
ethnicity and gender) often affect how an individual responds to treatment for drug
dependence. The purpose of this study is to determine the influence of baseline status and
population type on treatment response in cocaine dependent individuals. In addition, this
study will examine how various cocaine abuse medications target different neuronal systems,
withdrawal symptoms, and relapse to drug use.

This study will take place in two phases. Phase I will last 4 weeks; participants will
receive MI and undergo contingency-based urine tests in order to achieve the desired
baseline condition. Phase II will last 12 weeks. Participants in Phase II will be randomly
assigned to receive one of four treatments: 1) 50 mg naltrexone, 2) 800/200 mg
levodopa/carbidopa, 3) 400 mg modafinil, or 4) placebo. During Phase II, all participants
will receive psychotherapy and contingency management. Participants will complete urine drug
screening tests 3 times each week. Follow-up study visits will occur between 3 and 6 months
following Week 12, and will include objective and self-reported drug use.

Inclusion Criteria:

- Meets DSM-IV criteria for current cocaine dependence

Exclusion Criteria:

- Meet diagnostic criteria for other serious psychiatric symptoms and/or disorders that
would interfere with participation in the treatment study (e.g., psychosis; mania;
suicidal/ homicidal ideation) including other forms of drug dependence, nicotine and
cannabis excepted.

- Medical conditions contraindicating naltrexone therapy (e.g., past history of opioid
use in the 30 days prior to study entry or significant hepatocellular injury)

- Medical conditions contraindicating modafinil therapy (e.g., hypertension, seizures,
arrhythmia, or coronary artery disease)

- Medical conditions contraindicating levodopa/carbidopa therapy (e.g., severe
pulmonary/cardiovascular disease, narrow angle glaucoma, melanoma, history of peptic
ulcer, or renal function impairment)

- Requires certain medications

- Current or recent treatment for substance use or other psychiatric condition

- On parole or probation that requires reports of drug use to officers of the court

- Pending incarceration

- Pregnant or breastfeeding

- Unable to read, write, or speak English

- Plans to leave the study area within 3 months of study entry