• Cocaine use as measured by self report on the Time-Line Follow Back and confirmed with urine drug screen. [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
  
• Safety and tolerability as measured by adverse events, weekly evaluations, physical exams and laboratory testing. [ Time Frame: 8 weeks ] [ Designated as safety issue: Yes ]
  

The primary objective of the trial is to evaluate the safety, tolerability and efficacy of acamprosate for the treatment of 60 treatment seeking cocaine dependent outpatients. The study will be an exploratory, double-blind, placebo-controlled 9-week trial, with a 2-cell design (30 subjects per cell) in which either 1998 mg/day of acamprosate (666 mg TID) or placebo will be given. Study medications will be given by medical practitioners, trained to provide NIAAA's COMBINE Medical Management. In addition, patients will receive weekly individual psychosocial treatment sessions utilizing Cognitive Behavioral Therapy (CBT) at the University of Pennsylvania Treatment Research Center (TRC).

Primary Hypotheses:

1. Efficacy: Acamprosate-treated subjects will demonstrate less cocaine use during the medication/placebo treatment phase, compared to placebo-treated subjects. Cocaine use will be measured by self-report from the TLFB confirmed with urine assay for benzoylecgonine (BE)
2. Safety and Tolerability: Acamprosate-treated subjects and placebo-treated subjects will report similar rates of adverse events, assessed by weekly evaluations, physical exams and laboratory testing.

Secondary Hypotheses:

1. Acamprosate-treated subjects, compared to placebo-treated subjects, will report less craving for cocaine, measured by lower scores on the Brief Substance Craving Scale (BSCS) (Somoza et al, 1995) and Multiple Choice Procedure (MCP) (Griffiths et al., 1993) during the medication treatment phase.
2. Acamprosate-treated subjects, compared to placebo-treated subjects, will report fewer withdrawal symptoms, measured by the Cocaine Selective Severity Assessment (Kampman et al., 1998).
3. Acamprosate-treated subjects, compared to placebo-treated subjects, will report fewer mood and anxiety symptoms, measured by the Hamilton Depression Rating Scale (HAM-D) (Hamilton, 1967), Hamilton Anxiety Rating Scale (HAM-A) (Hamilton, 1969), and Clinical Global Impression Scale (CGI).
4. Subjects who are highly acamprosate-adherent (>80% pills taken, verified by combining patient report with blister cards) will have more cocaine non-use days during the medication treatment phase, compared to those who are less acamprosate-adherent (<80% pills taken).

Inclusion Criteria

1. Male and females 18 years of age or older.
2. Subject meets DSM-IV criteria for current diagnose of cocaine dependence, determined by The Structured Clinical Interview for DSM-IV (SCID-IV).
3. Subject used cocaine in the past 30 days totaling at least $200 worth of cocaine. Cocaine use will be determined by utilizing the modified Timeline Followback, crosschecked with the ASI, which inquires about dollar amounts spent on drug use.
4. Subject lives a commutable distance from the TRC and agrees to attend all research visits, including follow-up visits.
5. Subject speaks, understands, and prints in English.
6. Written informed consent signed by the subject.

Exclusion Criteria

1. Subjects mandated to treatment based upon a legal decision or as a condition of employment.
2. Subjects with evidence of current substance dependence other than cocaine, alcohol or nicotine dependence, as determined by the SCID-IV.
3. Subjects who meets DSM-IV criteria for current alcohol dependence who require a medical alcohol detoxification.
4. Requires treatment with any psychoactive medications, including any anti-seizure medications (with the exception of Benadryl used sparingly, if necessary, for sleep).
5. Has a lifetime DSM-IV diagnosis of bipolar affective disorder, schizophrenia or any psychotic disorder, or organic mental disorder. Has current DSM-IV diagnosis of any other clinically significant psychiatric disorder that will interfere with study participation, as determined by the study physician or PI (Drs. Kyle Kampman and Helen Pettinati).
6. Female subjects who are pregnant or lactating, or female subjects of childbearing potential who are not using acceptable methods of birth control. Acceptable methods of birth control include: barrier (diaphragm or condom) with spermicide, intrauterine progesterone contraceptive system, levonorgestrel implant, medroxyprogesterone acetate contraceptive injection, and oral contraceptives.
7. Clinical laboratory tests (CBC, blood chemistries, urinalysis) outside normal limits that are clinically unacceptable to the Principal Investigator. EKG-1st degree heart block, sinus tachycardia, left axis deviation, and nonspecific ST or T wave changes are allowed; liver function tests [LFTs] < 5 x ULN are acceptable. Eligibility will be determined by most recent lab results collected prior to randomization.
8. Subjects with impaired renal function as indicated by corrected creatinine clearance below 80 ml/min/70 kg as determined by the modified Cockcroft equation (Center for Disease Control, 1986).
9. Subjects who have any disease of the gastrointestinal tract, liver or kidneys that could result in a possibility of altered metabolism or excretion of the study drug. As it is not possible to enumerate the many conditions which might impair absorption, metabolism, or excretion, the investigators will be guided by evidence such as: History of major gastrointestinal tract surgery (gastrectomy, gastrostomy, bowel resection, etc) or a history of an active peptic ulcer or chronic disease of the GI tract (ulcerative colitis, regional enteritis, or gastrointestinal bleeding).
10. History of significant heart disease (an arrhythmia which required medication, angina pectoris, documented history of myocardial infarction, or heart failure).
11. Known hypersensitivity to acamprosate.
12. Subjects having participated in any investigational drug trial within 30 days prior to randomizing into the study.
13. Subjects with any serious illnesses that may require hospitalization during the study, as determined by the study physician or PI.