Effects of Labetalol on Nicotine Administration in Humans - 14

The purpose of this study is to determine whether labetalol, an alpha and beta adrenergic
blocker, will block the subjective and physiological effects of intravenously administered
nicotine in humans. A total of 12 subjects will participate in the double blind placebo
controlled, outpatient study. Subjects will have 3 separate experimental sessions 3-9 days
apart. On each of the experimental sessions, a single oral dose of low (100mg) or high dose
of labetalol (200mg ), or placebo will be administered. Two hours after labetalol or placebo
treatment, subjects will receive 15 variance grams nicotine base/kg intravenously. Several
physiological endocrine and subjective measures will be obtained during the sessions. We
propose that blockage of adrenergic receptors by labetalol will significantly block the
physological and subjective effects of nicotine.

Inclusion Criteria:

Male/Female, aged 21-55 years with a smoking history of at least 1 pack of cigarettes
daily for at least 1 year. In good health as verified by medical history, screening
examination, and screening laboratory tests.

Exclusion Criteria:

History of heart disease, peripheral vascular disease, COPD, any other medical condition
which physician investigator deems inappropriate for subject participation. Pregnant or
lactating or not using adequate birth control methods. Use of regular psychotropic
medication (antidepressants, antipsychotics, or anxiolytics and recent psychiatric
history). Chronic use of systemic steroids or antihistamines. Abuse of alcohol or any
other recreational or prescription drug. Regular use of any other tobacco products,
including smokeless tobacco and nicotine products.