Weight loss drug shows potential to treat opioid abuse

A new study suggests that the prescription weight-loss drug lorcaserin has potential as a new treatment for opioid use disorder. Tests on rats reveal that it not only reduces self-administration of oxycodone but also that it can weaken reaction to drug-taking cues, which are often associated with relapse.

The study – led by Kathryn A Cunningham, a professor of pharmacology and director of the Center for Addiction Research in the University of Texas Medical Branch at Galveston – is published in the journal ACS Chemical Neuroscience

Opioids are substances that attach to opioid receptors in parts of the brain that control painb and emotion. Examples include heroin, morphine, and certain prescription pain relievers such as oxycodone, codeine, and fentanyl.

While treatments for opioid use disorder exist, they are not ideal because they are often associated with high relapse rates and too many people stopping treatments early, note the authors of the new study.

One of the problems with many of the current treatments is that while they reduce the feeling of euphoria that results from taking opioids such as oxycodone, they do not address “cue reactivity” – the powerful effect that a familiar drug-taking environment can exert on anticipation of the drug experience.

Cue reactivity is often the reason that people on opioid misuse treatment relapse when they encounter the people, places, situations, and equipment that they associate with their opioid use. It results from the repeated pairing of these stimuli with the experience of the drug use.

In their new research, which takes the form of a preclinical study, the team shows that the prescription weight-loss drug lorcaserin reduced not only the use but also the craving for oxycodone

So, for the new study, the researchers allowed rats to give themselves oxycodone when they were exposed to a particular pattern of lights and sounds – thus creating a specific drug-taking environment.

After a period during which the rats got used to self-administering oxycodone in the drug-taking environment, the team withdrew the oxycodone. They exposed the rats to their familiar drug-taking environment and gave some of them lorcaserin and the rest a placebo.

They then allowed the rats to self-administer oxycodone again.

To confirm that this effect was due to lorcaserin, the researchers gave lorcaserin to a group of rats, plus a drug that blocks its effect by denying access to serotonin 2C receptors. These rats then “tried very hard” to self-administer the oxycodone.

The researchers say that the study shows that lorcaserin appears not only to reduce oxycodone self-administration, but also cue reactivity associated with relapse.

Professor Cunningham said that “The effectiveness of lorcaserin in reducing oxycodone seeking and craving highlights the therapeutic potential for lorcaserin in the treatment of opioid use disorder.”

The team is now planning to carry out further studies on drugs such as lorcaserin in order to better understand how they might help to tackle the opioid epidemic.