March 14, 2011 (Vienna, Austria) — The atypical antipsychotic agent quetiapine (Seroquel, AstraZeneca) appears to provide no benefit for the treatment of cocaine addiction, new research suggests.
Presented here at EPA 2011: 19th European Congress of Psychiatry, the study showed that quetiapine was no more effective than placebo for treating cocaine dependence in nonpsychotic individuals undergoing cognitive behavioral therapy (CBT).
"In clinical settings where cognitive behavioral groups are available, it does not appear that prescribing additional quetiapine is warranted since it would expose the individual to the risks of an antipsychotic medication without the expectation of benefit beyond the efficacy of group therapy," Andre Tapp, MD, director of ambulatory psychiatry at the Veterans Affairs Puget Sound Health System in Tacoma, Washington, told Medscape Medical News.
It is estimated that in the United States approximately 1.5 million people are cocaine dependent. However, despite the ongoing epidemic of cocaine use, there are no US Food and Drug Administration–approved medications for cocaine dependence.
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| Dr. Andre Tapp |
Several psychoactive compounds, including dopamine agonists, dopamine antagonists, antidepressants, and mood stabilizers, have been tested for this indication. Some of these compounds have shown promise in open-label studies, but few have demonstrated efficacy in randomized controlled trials.
Dopaminergic and serotonergic neurotransmitter systems are involved in cocaine use and cravings. Because atypical antipsychotics act on these neurotransmitter systems, there has been a lot of interest in their potential use for the treatment of cocaine addiction.
In a prior study of 22 nonpsychotic male veterans with cocaine dependence, these same investigators found that open-label quetiapine treatment reduced cravings and improved some aspects of cocaine dependence.
In the present study, 60 male and female veterans and nonveterans were randomized to 12 weeks' treatment with either quetiapine or placebo. In all cases, their diagnosis of cocaine dependence had been confirmed using the Structured Clinical Interview for DSM-IV disorders at screening, and all of participants reported using cocaine within the prior 30 days.
Participants who had been assigned to quetiapine initially received 50 mg/day, which was titrated up to 400 mg/day by the end of the second week. If an individual was not able to tolerate the prescribed dosage during the titration phase or at any time during treatment, the active drug was reduced to 300, 200, 100, or 50 mg/day as tolerated. If an individual was unable to tolerate the 50-mg/day dose, he/she was removed from the drug portion of the study.
Subjects presented to the clinic each week for group CBT and a urine drug screen. They were also asked about their cocaine use and money spent on cocaine during the past week.
Overall, 68% of individuals dropped out of the study prematurely. However, this rate is typical for individuals with cocaine dependence, Dr. Wood said. There were no significant differences in dropout rates between the 2 groups (χ2 [1] = 0.20, P = .65).
The analysis showed a main effect for reductions in self-reported cocaine use (F2,21 = 4.71, P = .02; partial x = .31) and self-reported money spent on cocaine (F2,21 = 4.20, P = .03, partial x = .32) during the study. However, group differences were not significant (all P >.25).
The most common adverse effects were drowsiness/hypersomnia and dry mouth, both of which were more common in the quetiapine group.
"While subjects as a whole improved by decreasing their cocaine use, the quetiapine group did not show any significant differences from the placebo group," said Dr. Tapp. "The data thus indicate that quetiapine was not effective for reducing cocaine use."
He added that because all subjects in this study underwent CBT, it is not possible to determine from this study how quetiapine would perform against a true placebo in which case patients would receive no treatment.
He called for future studies to examine whether quetiapine can help patients with cocaine dependence in settings where CBT is not available.
"Unfortunately, no medication has proven effective in the treatment of cocaine dependence," Merrill Herman, MD, program director of the Addiction Psychiatry Fellowship and associate clinical professor, Department of Psychiatry and Behavioral Sciences at Albert Einstein College of Medicine-Montefiore Medical Center in New York City, told Medscape Medical News.
"As the study demonstrates, quetiapine is not effective for cocaine addiction. However, preliminary studies suggest that the wakefulness agent modafanil may hold some promise."
For now, said Dr. Herman, the only modalities shown to be effective for cocaine dependence are of a nonpharmacologic nature, including CBT with relapse prevention techniques.
"Maybe a medication will be developed in the future to work in conjunction with psychosocial approaches," he added.
The study was funded by an Investigator-Initiated Grant from AstraZeneca Pharmaceuticals and received institutional support through the Mental Illness Research Education and Clinical Center at the VA Puget Sound Health Care System. Dr. Tapp is a member of the AstraZeneca Pharmaceuticals LP Speakers Bureau.
EPA 2011: 19th European Congress of Psychiatry: Abstract 861. Presented March 13, 2011.
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