The purpose of this study is to assess potential interactions between intravenous (IV) cocaine and treatment with lofexidine.

To determine the safety of daily oral lofexidine alone and concurrent with IV cocaine infusions of 20 mg and 40 mg in cocaine-experienced, non-opiate-addicted volunteers.

Inclusion Criteria:

• Be volunteers who meet Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) criteria for cocaine abuse or dependence and are non-treatment seeking at the time of the study.

• Be between 18 and 50 years of age, inclusive.

• Be currently use cocaine. Use must be confirmed by a positive urine test for cocaine metabolites once within the outpatient screening period.

• Be able to verbalize understanding of the consent form and provide written informed consent.

• Females must have a negative pregnancy test within 72 hours prior to receiving the first infusion of cocaine. They must also be postmenopausal, have had a hysterectomy, been sterilized, or agree to use one of the following methods of birth control:

  • diaphragm and condom by partner
  • intrauterine device (that does not contain progesterone) and condom by partner
  • sponge and condom by partner
  • complete abstinence from sexual intercourse

Note: Oral contraceptives, Depo-Provera, Norplant, Patch, and intrauterine progesterone contraceptive system are not allowed.

Exclusion Criteria:

• Please contact site for more information