Interactions Between Intravenous (IV) Cocaine and 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