Navigation Links
Possible Reason for Rimonabant's Side Effects Discovered
Date:3/12/2008

Weight-loss drug not approved in U.S. may block brain receptor among some users

WEDNESDAY, March 12 (HealthDay News) -- The weight-loss drug rimonabant has been associated with troubling psychiatric side effects, and now researchers think they have discovered why.

A receptor in the brain called TRPV1, which is central to learning and memory, may be blocked by large doses of rimonabant (Acomplia), resulting in depression, anxiety and suicidal thoughts among some people taking the drug, a new study shows.

"We think that changes in the strength of connections between neurons in the brain underlie all kinds of important changes in the brain like learning, the development of the nervous system and many other adaptations to the environment, such as responses to pain and responses to drugs," said lead researcher Julie Kauer, an associate professor of molecular pharmacology, physiology and biotechnology at Brown University in Rhode Island.

The report was published in the March 13 issue of Neuron.

In experiments with rat brains, Kauer's group found that TRPV1 controls a brain mechanism called long-term depression, which is thought to be a key component in memory. The team thinks this finding may relate to the psychiatric side effects that have been seen with Acomplia.

"We found that rimonabant blocked TRPV1, and also another receptor CB1. It's possible that when the patient takes the drug, and the dose range is correct, it may not affect TRPV1 at all," Kauer said. "However, in some patients, Acomplia could be hitting TRPV1 and may well have an effect on activating this receptor," she said.

Acomplia is used widely outside the United States. To date, the U.S. Food and Drug Administration has not approved Acomplia because of its psychiatric side effects.

In addition, the researchers found that a new class of painkillers may interfere with learning and memory, because they also block TRPV1.

"They're all these other drugs that are supposed to target peripheral pain, and there hasn't been a lot of attention paid to whether they cross into the brain, Kauer said. That's something that needs to be paid attention to, because now we're showing that these drugs are depressing brain synapses," she said.

One expert thinks the study may have identified the reason for mood disorders associated with Acomplia, but it doesn't speak to the issue of whether the drug's benefits outweigh the risks.

"This is an interesting study which is important in potential mechanisms that could explain the higher incidence of mood disorders associated with rimonabant use," said Dr. Raj Padwal, an assistant professor of general internal medicine at the University of Alberta in Canada.

However, Padwal, who has studied the risks and benefits of weight-loss drugs, thinks there are still questions about whether the drug causes mood disorders or not.

"If it does cause mood disorders, what is the increased risk? Does the increased risk of mood disorders then outweigh the potential benefits of the drug such that the drug should not be approved?" Padwal asked.

This study is nice in elucidating potential mechanisms but not really helpful in teasing out whether the drug should be approved, Padwal said. "For approval, I'm sure the FDA is looking for post-marketing surveillance data from Europe and other countries of the world in which the drug is being used," he added.

More information

For more on obesity, visit the National Institutes of Health.



SOURCES: Julie Kauer, Ph.D., associate professor, molecular pharmacology, physiology and biotechnology, Brown University, Providence, R.I.; Raj Padwal, M.D., assistant professor, general internal medicine, University of Alberta, Edmonton, Canada; March 13, 2008, Neuron


'/>"/>
Copyright©2008 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Teamsters Warn of Possible Work Stoppages, Service Disruptions at AmerisourceBergen
2. Researchers find possible target to treat deadly bloodstream infections
3. Brain stress system presents possible treatment
4. Good Outcomes Possible for Older Lung Transplant Patients
5. Yale study offers insight into possible cause of lymphoma
6. Vaccine for stomach flu may be possible, UNC research shows
7. Childrens Hospital scientists identify possible target for prevention and treatment of pneumonia
8. Model found to determine cause, possible treatment of nerve tumors
9. Contact lenses with circuits, lights a possible platform for superhuman vision
10. Protein a possible key to allergy and asthma control
11. Possible Cure for Rare Lymphoma Reported
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Possible Reason for Rimonabant's Side Effects Discovered 
(Date:6/25/2016)... , ... June 25, 2016 , ... Conventional wisdom preaches ... success. In terms of the latter, setting the bar too high can result in ... than just slow progress toward their goal. , Research from PsychTests.com ...
(Date:6/24/2016)... ... ... was in a crisis. Her son James, eight, was out of control. Prone to extreme ... “When something upset him, he couldn’t control his emotions,” remembers Marcy. “If there was ... other children and say he was going to kill them. If we were driving ...
(Date:6/24/2016)... ... June 24, 2016 , ... Comfort Keepers® of San Diego, CA is excited ... To Recovery® program to drive cancer patients to and from their cancer treatments. ... highest quality of life and ongoing independence. Getting to and from medical treatments ...
(Date:6/24/2016)... ... June 24, 2016 , ... The Haute ... Dr. Barry M. Weintraub as a prominent plastic surgeon and the network’s newest ... world, and the most handsome men, look naturally attractive. Plastic surgery should be ...
(Date:6/24/2016)... ... June 24, 2016 , ... Venture Construction Group (VCG) ... held on June 20th at the Woodmont Country Club at 1201 Rockville Pike, Rockville, ... dedicated to helping service members that have been wounded in battle and their families. ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... 2016 Dehaier Medical Systems Ltd. (NASDAQ: ... markets and sells medical devices and wearable sleep respiratory ... strategic cooperation agreement with Hongyuan Supply Chain Management Co., ... June 20, 2016, to develop Dehaier,s new Internet medical ... Dehaier will leverage Hongyuan Supply Chain,s sales platform to ...
(Date:6/24/2016)... , June 24, 2016 ... Market by Type (Standard Pen Needles, Safety Pen Needles), ... (Insulin, GLP-1, Growth Hormone), Mode of Purchase (Retail, Non-Retail) ... MarketsandMarkets, This report studies the market for the forecast ... to reach USD 2.81 Billion by 2021 from USD ...
(Date:6/24/2016)...  Arkis BioSciences, a leading innovator in the ... cerebrospinal fluid treatments, today announced it has secured ... led by Innova Memphis, followed by Angel Capital ... Arkis, new financing will accelerate the commercialization of ... of its in-licensed Endexo® technology. ...
Breaking Medicine Technology: