Navigation Links
Paxil Blocks Tamoxifen, Lowers Survival Odds Against Breast Cancer

Patients should avoid taking the two drugs together, researchers say ,,

MONDAY, Feb. 8 (HealthDay News) -- Women with breast cancer who take both tamoxifen and the antidepressant Paxil may increase their risk of dying because Paxil reduces tamoxifen's effectiveness, Canadian researchers report.

"Paxil can deprive women of the benefit of tamoxifen, especially when it is used in combination with tamoxifen for a long time," said lead researcher Dr. David Juurlink, division head of clinical pharmacology and toxicology at Sunnybrook Health Sciences Center in Toronto.

"Patients who are on tamoxifen and who require an antidepressant should probably be given something different," he added.

Paroxetine (Paxil) is a selective serotonin reuptake inhibitor (SSRI) that significantly inhibits an enzyme called cytochrome P450 2D6, which is needed to metabolize tamoxifen into its active form. But this dampening effect was not seen with certain other SSRIs evaluated, including citalopram (Celexa) and venlafaxine (Effexor), the researchers said.

Patients taking Paxil and tamoxifen should talk with their doctors about changing their antidepressant, Juurlink said.

But he advised against abruptly discontinuing Paxil.

"There is a very real danger to stopping Paxil suddenly. There is a well-described withdrawal syndrome and the risk of depression becoming more severe," he said.

In addition, any transition to another antidepressant should be done gradually over several weeks, he said.

The report is published in the Feb. 8 online edition of the British Medical Journal.

For the study, Juurlink's group looked at the medical records of 2,430 women with breast cancer who began taking tamoxifen between 1993 and 2005. About 30 percent of the women were also taking an antidepressant, Paxil being the most common. Antidepressants are often prescribed to reduce hot flashes associated with tamoxifen in addition to easing symptoms of depression.

Paxil plus tamoxifen was linked to an increased risk of dying from breast cancer, and the risk increased with the amount of time the drugs were taken together, the researchers found.

Taking Paxil for 41 percent of the time that tamoxifen was also taken resulted in one extra death from breast cancer within five years of stopping tamoxifen among every 20 women taking the drugs simultaneously, Juurlink's team estimated. The more time the drugs were taken together, the greater the risk, they added.

SSRIs inhibit CYP 2D6 to varying degrees, the authors said, noting Paxil is "exceptionally potent" in that respect.

Dr. Frank Andersohn, a senior research associate at the Institute for Social Medicine, Epidemiology, and Health Economics at Charite University Medical Center in Berlin, Germany, and author of an accompanying journal editorial, said that "physicians should be aware that paroxetine and other strong 2D6-inhibiting drugs should be avoided in women treated with tamoxifen."

Fluoxetine (Prozac) is also a strong 2D6 inhibitor, the authors noted.

Another expert, Dr. Harold J. Burstein, said this paper adds to the substantial literature suggesting that drugs that affect the metabolism of tamoxifen might affect breast cancer outcomes for women taking tamoxifen.

"While the results should not alarm patients currently taking SSRIs, they do suggest that, as a practice style, patients on tamoxifen who also need SSRIs should probably seek out agents such as Effexor in preference to Prozac or Paxil," said Burstein, clinical investigator in the breast oncology center at Dana-Farber Cancer Institute, Brigham and Women's Hospital in Boston.

"The findings are also a reminder that each drug that a patient takes should be thought through carefully. If there are drugs that aren't needed, then they aren't needed and can be omitted," he added.

More information

For more information on breast cancer, visit the American Cancer Society.

SOURCES: David Juurlink, M.D., Ph.D., division head, clinical pharmacology and toxicology, Sunnybrook Health Sciences Center, Toronto; Frank Andersohn, M.D., senior research associate, Institute for Social Medicine, Epidemiology, and Health Economics, Charite University Medical Center, Berlin; Harold J. Burstein, M.D., Ph.D., clinical investigator, breast oncology center, Dana-Farber Cancer Institute, Brigham and Women's Hospital, and associate professor, medicine, Harvard Medical School, Boston; Feb. 8, 2009, British Medical Journal, online

Copyright©2010 ScoutNews,LLC.
All rights reserved

Related medicine news :

1. Ennis & Ennis, P.A. Announces Nationwide Free Legal Consultations For Users of Paxil
2. Glaxo Official Memo Urged Scientists to Withhold Information About Paxils Risks, Trial Hears; Pharmaceutical Industry Today Offers Complete News Coverage
3. Proposed Settlement Will Make Up to $28 Million Available to Individuals Who Purchased and Companies That Reimbursed for Paxil CR(R)
4. Prolactin blocks oncogene associated with poor prognosis in breast cancer
5. Idahos Health Care Woes Need Solutions, Not More Roadblocks
6. Drug Combo Blocks HIV Infection in Mice
7. Undocumented Hispanics Face Health Care Roadblocks in U.S.
8. New chemo cocktail blocks breast cancer like a strong fence
9. U.S. Leadership in Medical Innovation Depends on Education and Immigration Policy, Say Experts at Capitol Hill Briefing on Education & Immigration: Building Blocks of Innovation
10. Council for American Medical Innovation to Host Capitol Hill Breakfast Briefing on Education and Immigration: The Building Blocks of Innovation
11. Federal Judge Orders Schwarzenegger Administration to Comply with Order That Blocks State Reduction for IHSS Worker Wages
Post Your Comments:
(Date:6/27/2016)... Park, KS (PRWEB) , ... June 27, 2016 , ... ... in retailers of Eyeglasses . , Millions of individuals in the United States ... eyeglasses have become a way to both correct vision and make a fashion statement. ...
(Date:6/26/2016)... ... ... a legally blind and certified personal trainer is helping to develop a weight loss fitness ... to fix the two major problems leading the fitness industry today:, , ... They don’t eliminate all the reasons people quit their exercise program ...
(Date:6/25/2016)... ... 25, 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX users can ... CEO of Pixel Film Studios. , ProHand Cartoon’s package transforms over 1,300 hand-drawn ... X . Simply select a ProHand generator and drag it above media or text ...
(Date:6/25/2016)... ... June 25, 2016 , ... Conventional wisdom preaches the benefits of moderation, whether ... latter, setting the bar too high can result in disappointment, perhaps even self-loathing. However, ... their goal. , Research from reveals that behind the tendency ...
(Date:6/24/2016)... ... June 24, 2016 , ... ... Scientific Sessions in Dallas that it will receive two significant new grants to ... came as PHA marked its 25th anniversary by recognizing patients, medical professionals and ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... , June 23, 2016  MedSource announced ... as its e-clinical software solution of choice.  This ... best possible value to their clients by offering ... The preferred relationship establishes nowEDC as the EDC ... for MedSource,s full-service clients.  "nowEDC has long been ...
(Date:6/23/2016)... 23, 2016 Research and Markets ... Market by Type (Organic Chemical (Sugar, Petrochemical, Glycerin), Inorganic ... Coating, Parenteral) - Global Forecast to 2021" report ... The global pharmaceutical excipients market is projected to ... of 6.1% in the forecast period 2016 to 2021. ...
(Date:6/23/2016)... 2016 Research and Markets has announced ... Analysis 2016 - Forecast to 2022" report to their ... contains up to date financial data derived from varied research ... trends with potential impact on the market during the next ... which comprises of sub markets, regional and country level analysis. ...
Breaking Medicine Technology: