Ritanserin reduces abuse of alcohol, cocaine, and fentanyl in rats.

Rats that had received 3% alcohol, 0.01% cocaine, or 0.002% fentanyl as the only beverage over 10 days showed marked preference for the drug solution when water was made available as a second fluid in a separate bottle. Treatment with low doses of ritanserin, a specific central serotonin 5-HT2 antagonist, rapidly reversed drug preference without changing total fluid intake. Quantitatively, the reduction in drug consumption was greater for alcohol than for cocaine and greater for cocaine than for fentanyl. This is probably related to differences in the reinforcing potential of the three drugs.