Aripiprazole, a drug used in the treatment of bipolar disorder and schizophrenia, may also help in treating alcohol dependence, a new study has found.
The study, led by Henry R. Kranzler, a professor in the department of psychiatry at the University of Connecticut Health Center, discovered that aripiprazole significantly and dose-dependently increases the sedative effects of alcohol and, to a lesser degree, decreases the euphoric effects of alcohol.
"Aripiprazole is a dopamine partial agonist. Since dopamine is involved in the rewarding effects of alcohol, we thought that aripiprazole might reduce those effects," said Kranzler.
"Aripiprazole is an unusual drug in that it has different pharmacological effects at different doses and it might do one thing acutely and another during chronic dosing. In general, it appears to have the potential to reduce drinking if you get the dose right for an individual patient. More work needs to be done to 'fine tune' its effectiveness, which is what this study attempts to do," said Raymond F. Anton, professor and director of the Clinical Neurobiology Laboratory at the Medical University of South Carolina.
For the study, 18 social drinkers from the community were recruited including nine men and nine women between the ages of 21 and 45 years of age. All of them had to undergo three experimental sessions in a randomized sequence; receiving on the day before the laboratory session either no medication, or 2.5 mg or 10 mg of aripiprazole.
During each session, participants consumed three standard drinks, for a total of 0.8 g/kg of alcohol for the men, and 0.7 g/kg for the women. Throughout the laboratory sessions the researchers regularly measured breath alcohol concentrations, heart rate, blood pressure, static ataxia (body sway), and subjective effects.
"Findings show that aripiprazole made the drinkers sleepier and they experienced less pleasure from alcohol than they might have without it," said Kranzler.
Anton added: "Aripiprazole might 'shift the balance' from alcohol being more stimulating to being more sedating. This has implications for both treatment and side-effect management for people taking this medication, [becoming] a balance of useful versus aversive effects. Most other dopamine-blocking drugs have too many aversive [or side] effects that make them not suitable for treatment of alcohol-use disorders. Aripiprazole might be more tolerated and have less long-term negative effects."
Kranzler further explained: "Other antipsychotic drugs - such as haloperidol and, olanzapine, which are full dopamine antagonists - reduce the pleasurable effects of alcohol, but they are associated with more adverse effects than aripiprazole is. The list of side effects associated with most medications that exert powerful enough effects to be of value in treating psychosis is long. The ones that occur substantially more commonly than with placebo are headaches, insomnia, nausea, dizziness, and vomiting."
"These findings help to demonstrate that alcohol has effects on many different brain chemicals and, as such, that many different treatment approaches for alcohol dependence may be useful. That having been said, it's unclear whether aripiprazole will be very useful in this effort because its side effects may outweigh its beneficial effects," he concluded.
The results of this study are published in the latest issue of Alcoholism: Clinical and Experimental Research.