Acute Withdrawal From Smoked Cocaine - 9

Although there are clearly identifiable withdrawal syndromes following cessation of a number
of abused drugs such as alcohol and heroin, it is unclear whether a withdrawal syndrome
follows the cessation of crack cocaine. A laboratory model of withdrawal from smoked (crack)
cocaine would provide a safe and systematic method of testing the efficacy of behavioral or
pharmacological treatments for withdrawal symptoms following cocaine smoking cessation.
Therefore, this study investigated acute behavioral, subjective, and physiological
withdrawal symptomatology for 6 hrs following 7 deliveries of 2 dose sized (0.07 vs. 0.4
mg/kg) of smoked cocaine. The behavioral measure was performance on a computerized reaction
time task, subjective measures included participant and observer ratings of mood and
withdrawal symptomatology, and physiological measures comprised heart rate and blood
pressure. It was hypothesized that signs and symptoms of withdrawal from smoked cocaine
would be greater following the 0.4 mg/kg dose size, compared to the 0.07 mg/kg dose size.

Inclusion Criteria:

M/F ages 21-45 with a history of smoked cocaine use at least twice a week for the past six
months, including 0.5 g of cocaine in a 24hr period on at least one occasion. In good
health as evidenced by physical exam and complete blood count, chest X-ray and electrolyte
and liver function tests, with a normal resting 12-lead electrocardiograph (ECG) and blood
pressure of less than 140/90 mmHg. Using an acceptable method of birth control. Having a
urine toxicology screen positive for cocaine metabolites.

Exclusion Criteria:

Any DSM-IV Axis I disorder other than cocaine abuse or dependence, or dependence or daily
use of psychoactive drugs other than nicotine or caffeine. A history of violence and/or
currently on probation, parole or awaiting trial. Pregnant as determined by serum
pregnancy screen, lactating or having delivered a child in the past 12 months.
Seropositive tests for the human immunodeficiency virus (HIV) or hepatitis B. History of
seizure disorder.