The intent of this study is to see if the rate that the body breaks down l-methamphetamine (l-MA) could be used as an accurate estimate for the rate that the body breaks down d-methamphetamine (d-MA). l-MA is sold over the counter as a nasal decongestant where as d-MA is the commonly abused form of methamphetamine.

Subjects will screen at St. Luke's Hospital in San Francisco to determine their eligibility.

Once enrolled the study will take two weeks. During the first week subjects attend daily, hour-long outpatient visits at San Francisco General Hospital. At these visits subjects will receive an oral dose of l-methamphetamine, have their vitals read, answer questionnaires and receive a blood draw.

During the second week of the study subjects are admitted to San Francisco General Hospital for a week long inpatient stay. During this stay the subject continues to receive l-methamphetamine but also receives three doses of d-methamphetamine on three separate days. In addition the subject receives blood draws, has their urine collected, and answers questionnaires.

Inclusion Criteria:

• Healthy Males and Females Between the Ages of 18 and 50
• Must have some experience with methamphetamine