A Study of Baclofen ER

Inclusion Criteria: 1. Physically healthy cocaine-dependent (based on DSM-IV- TR criteria) male or female aged 18-60 yrs, voluntarily seeking treatment for cocaine dependence. 2. Females must be non-pregnant, non- lactating and either be of non-childbearing potential (i.e. sterilized via hysterectomy or bilateral tubal ligation or at least 1 year post-menopausal) or of child bearing potential, but practicing a medically acceptable method of birth control. Examples of medically acceptable methods for this protocol include barrier (diaphragm or condom) with spermicide, an intrauterine device (IUD), oral contraceptives, a levonorgestrel implant, intrauterine progesterone contraceptive system, medroxyprogesterone acetate contraceptive injection, and abstinence. 3. Reading level at or above eighth grade. 4. Participants provide voluntary informed consent. 5. Smoking is primary route of cocaine administration. 6. Available for an inpatient stay. Exclusion Criteria: 1. Participation in clinical trial and receipt of investigational drug(s) during previous 60 days, except as explicitly approved by the Principal Investigator. 2. Clinically significant cardiovascular, hematologic, hepatic, renal, neurological or endocrinological abnormalities. 3. History of serious head trauma or injury causing loss of consciousness that lasted more than 3 minutes or associated with skull fracture or inter-cranial bleeding or abnormal MRI. 4. Presence of magnetically active prosthetics, plates, pins, broken needles, permanent retainer, bullets, etc. in patient's body (unless a radiologist confirms that its presence is unproblematic). An x-ray may be obtained to determine eligibility. 5. Claustrophobia or other medical condition that disables the participant from lying in the MRI for approximately 60 minutes. 6. Current or prior gambling problems (assessed by participants self-report) 7. Non-removable skin patches 8. Have received medication that could interact adversely with baclofen, including muscle relaxants (including tricyclic antidepressants), antiseizure medication, CNS depressants (tranquilizers, sleeping pills), MAO inhibitors), within the time of administration of study agent based on the study physician's guidance (e.g. 5 half lives) 9. Have known or suspected hypersensitivity to baclofen. 10. Be taking baclofen for any reason currently or during the past year.