Effects of Labetalol on Human Cocaine Use - 8

The goal of this study was to investigate the safety and utility of labetalol an alpha and
beta adrenergic block, for cocaine dependence in humans. A total of 12 subjects were
enrolled in this double blind, placebo controlled outpatient study. After baseline measures
are obtained, three experimental sessions were held at least 2 days apart. Subjects were
administered a single low (100 mg) or high dose of labetalol (200mg) or placebo on each of 3
experimental sessions. The labetalol doses were given in ascending order and the placebo
treatment were randomly inserted into the sequence. A single dose of smoked cocaine (0.4
mg/kg) was administered 2 hrs after labetalol or placebo treatment. During the sessions,
several subjective, behavioral and physiological measures were obtained.

Inclusion Criteria:

Male/Female ages 20-55. History of smoked or intravenous cocaine use on the average of at
least once a week over a six month period. Current history of good health and normal EKG.
Not pregnant as determined by pregnancy screening nor breat feeding and using acceptable
birth control methods (e.g. birth control pills diaphragm, condoms, plus foam) during the
study.

Exclusion Criteria:

Current problems with major psychiatric illnesses including bipolar disorder,
schizophrenia, or anxiety disorders. Current dependence on alcohol or on durgs other than
cocaine. History of major medical illnesses including asthma and chronic obstructive
pulmonary disease. Currently on a drug related parole or probation. Treated for chemical
dependency within the past 6 months.