The purpose of this study is to determine the effects of phenytoin on the
self-administration of smoked cocaine.
The purpose of this study was to determine the effects of phenytoin on smoked cocaine-base
self-administration using our laboratory self-administration model. A total of 12 patients
randomized, 6 to phenytoin and 6 to placebo treatment group. There were 2 phases in this
10-day inpatient study. Phase 1 subjects underwent one cocaine self-admin session.
Randomization took place at the start of Phase 2, Day 4 where subjects received either
placebo or phenytoin. The subjects assigned to phenytoin treatment received an oral loading
dose (20mg/kg) aimed at achieving plasma phenytoin concentration of (10-20 mg/L). During
Phase 2, subjects had the opportunity to self-administer cocaine on Days 5, 7, and 9. The
plasma phenytoin levels were expected to decrease gradually during Phase 2 which provided an
opportunity to study the effect of decreasing phenytoin plasma concentrations on cocaine
Males/Females between the ages of 20-40. History of smoked cocaine use on the avg. of at
least 2 times/week over a 6 month period. Have currently used at least 1 g of cocaine
within a 4-6 hr period. Current history of good health, normal serum albumin levels and
normal QTc intervals. Nonreactive for HIV. No participation in any of our studies for the
past 6 months. For females: 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).
History of suicide attempt, bipolar disorder, schizophrenia, or generalized anxiety
disorder. Current problem with major depressive disorder. Current use of alcohol or other
durgs on a daily basis. History of major medical illnesses. Currently on parole, probation
or a legal history of violence. Treated for chemical dependency within the past 6 months.
Use of any psychotropic drugs including MAOIs in the past 6 months.