A New Pharmacotherapy for Alcohol Dependence: Olanzapine

The first goal of the study is to determine whether olanzapine is effective at reducing
cue-elicited craving (i.e., subjective craving as well as activation of the midbrain and
prefrontal cortex after exposure to alcohol cues) for alcohol and reducing alcohol use in a
sample of alcohol dependent subjects. The second goal is to test the putative mechanism of
change by determining whether the effect of olanzapine on alcohol use behavior is mediated
by the effect of olanzapine on cue-elicited craving. The final goal will be to examine
whether genetic differences moderate the effects of olanzapine. [The polymorphism examined
here involves the D4 dopamine receptor gene (DRD4), which has a variable number of tandem
repeats (VNTR) in exon 3 (Van Tol et al., 1992). With respect to the DRD4 VNTR, individuals
with at least one copy of an allele with 7 or more repeats are hereafter referred to as DRD4
L individuals, and individuals with alleles that have fewer than 7 repeats are hereafter
referred to as DRD4 S individuals.]

In addition to laboratory studies on dopamine antagonists and alcohol craving (e.g., Modell
et al., 1993; Hutchison et al., 2001), recent clinical reports have suggested that
clozapine, a potent D4 receptor antagonist, reduces substance abuse among individuals with
comorbid substance abuse/dependence (Green et al., 1999; Zimmet et al., 2000; Lee et al,
1998) and specifically, alcohol use (Drake et al., 2000). Animal studies have also suggested
that clozapine reduces the voluntary intake of nicotine (Kameda et al., 2000). Given some of
these early findings, we conducted a laboratory test of the effects of olanzapine on
cue-elicited craving and craving after alcohol consumption among heavy social drinkers
(Hutchison et al., 2001). We decided to test olanzapine because it also targets the D4
receptor, although not as strongly as clozapine, and because olanzapine had the best side
effect profile among FDA approved medications that target dopamine receptors more broadly,
and the D4 more specifically. This initial test demonstrated that olanzapine attenuated the
effects of alcohol cues on two separate measures of urge to drink across two separate
experimental sessions and that olanzapine prevented increases in urge to drink after alcohol
consumption. With respect to the effects on urge to drink, the findings of this study are
generally consistent with the theoretical premise that this appetitive behavior is partially
mediated by mesolimbic dopamine activation.

To replicate and extend our previous results with olanzapine, a second study was designed to
examine whether olanzapine (5 mg) reduced craving as compared to cyproheptadine (4 mg),
which was used as an active control medication. It is important to note that there are no
other published studies (to our knowledge) that have used such a stringent experimental
control in a test of a pharmacological agent that targets alcohol craving in humans. For
example, previous studies with naltrexone have utilized a placebo control only. The results
from this investigation indicated that olanzapine and cyproheptadine produced equivalent
levels of sedation. However, olanzapine significantly reduced craving before and after
consuming alcohol, as compared to cyproheptadine (Hutchison et al., 2003). Moreover, there
was a significant medication by DRD4 VNTR polymorphism interaction such that olanzapine
reduced alcohol-elicited craving, particularly among DRD4 L individuals. To extend these
findings, we conducted a 12 week, randomized, double-blind trial of olanzapine in the
treatment of alcohol dependence (Hutchison et al., in press). Consistent with our previous
studies, the results suggested that olanzapine reduced cue elicited craving and alcohol
consumption significantly among DRD4 L individuals, but not DRD4 S individuals. Both of
these last two studies were conducted at the Boulder GCRC.

Here, a double-blind, placebo-controlled 3 (Medication: olanzapine 5 mg, olanzapine 2.5 mg,
vs. placebo) x 7 (Time: Baseline, 2, 4, 8, 12, 24, 36 weeks) mixed factorial design, where
medication is a between-subjects factor and time is a within-subjects factor, will be used
to test the treatment outcome hypotheses. Subjects will be randomly assigned to receive
either olanzapine (5 mg), olanzapine (2.5 mg), or placebo for a period of 12 weeks such that
there are equal numbers of DRD4 L individuals in each medication group. All subjects will
also receive 7 sessions of medication management / supportive therapy (detailed below).
Follow-up assessments will be obtained at 4, 8, 12 weeks (the end of treatment), 24 weeks,
and 36 weeks.