Phase 1 Naltrexone-Bupropion-Methamphetamine Interaction Study

Inclusion Criteria: * Are MA experienced but not dependent, males or females aged 21-to-50 years. * Reported use of MA during the past six months without experiencing an adverse consequence plus a life time MA or amphetamine use history of at least four occasions of use. * Have a body mass index (BMI) between 18 and 30. * Are willing and able to give written consent. * Are not currently a subject (including still in the follow-up period) of another drug research study. * Have no medical contraindications determined by the following: an adequate medical history, a physical examination including vital signs, 12-lead ECG, hematology, blood chemistry, and urinalysis. * Have a negative drug test for barbiturates, benzodiazepines, opiates, cocaine, amphetamines and ethanol at the time of hospital admission (Day 0). * Are females who have a negative pregnancy test at hospital admission. * Are of either non-childbearing (tubal ligation or total hysterectomy) or of childbearing potential using one or more of the following barrier methods of contraception: male or female condoms (with/without spermicide), diaphragm (with spermicide) and/or copper containing intrauterine device (with/without spermicide). No other contraceptives are acceptable. Exclusion Criteria: * Please contact site for more information