Tamoxifen Side Effects Can Hamper Memory, Cognitive Ability: Study
Published: February 17th, 2010 • Comments: 13
The results of a new study suggest that side effects of tamoxifen, a breast cancer drug, can lead to decreased cognitive abilities and memory loss.
Women who took tamoxifen for a year or more were found to score lower on verbal memory and executive functioning tests, according to researchers at the Netherlands Cancer Institute in Amsterdam. Their results were published this month in the online version of the Journal of Clinical Oncology.
Tamoxifen was first approved by the FDA in 1971 for the treatment of breast cancer. Originally developed by AstraZeneca under the brand name Nolvadex, it is now sold under a variety of brand names, including Istubal and Valodex, and is also sold as a generic. Tamoxifen works by inhibiting the development of estrogen, which is believed to stimulate the spread of breast cancer. As of 2004, it was the largest selling hormone-based breast cancer treatment drug in the world.
Dutch researchers, funded by Pfizer, tested 299 women, including 80 women prescribed tamoxifen and 99 women taking Pfizer’s competing Aromasin (exemestane). They found that tamoxifen users had a statistically significant drop in verbal memory and executive functioning skills when compared to healthy control groups. Aromasin users showed no significant cognitive differences, researchers said.
Executive functioning includes the ability to shift attention between two different parts of a task. Verbal memory is the ability to retain and recall spoken information.
Researchers were at a loss to explain why tamoxifen caused a drop in cognitive abilities, but there have been a number of studies that link estrogen with verbal memory, including a 2004 study by U.S. researchers who found that estrogen boosted long-term memory in men, and other studies that suggest women tend to have better verbal memory skills than their male counterparts.
The results of the new study comes on the heels of other research involving the drug, published in the most recent issue of the British Medical Journal, which found that selective serotonin reuptake inhibitors (SSRIs), like Paxil, can interfere with tamoxifen, reducing or completely mitigating the breast cancer drug’s effects. SSRIs are often prescribed to breast cancer patients to combat depression.
Comment by Cathy on 19 February 2010:
There have been no studies of the side effects of Tamoxifen use in men but I now have an explanation for the cognitive loss my husband suffered while receiving this treatment for Male Breast Cancer.
Comment by Elizabeth on 7 March 2010:
I have been on tamoxifen since 10/07.
Recently I have wondered if I have been experiencing a form of early dementia…I am currently teaching at the ocllege level and I have poor recall of the material that I presented at prior classes, my writing has suffered, I don’t have the saame abilities to ‘multi-task’—I have to do things in a much nore linear fashion…and not do too many things. An obgyn nurse practitioner mentioned this study. I’m not sure where to go from here…I am also on Zoloft. Any thoughts out there?
Comment by Cyndi on 14 April 2010:
I took Tamoxifen for 5 yrs. I do have memory loss now. I also just found out that taking tamoxifen & antidepressents make the tamoxifen not work. Took Prozac while taking tamoxifen. Now I am wondering what might happen next, if the tamoxifen didn’t work. I am going to talk with my onocoligist.
Comment by Julia on 5 May 2010:
I had a double mastectomy on 2001 after kemo treatment I took Arimidex for 4 years and the doctor change it to Aromasin due to a lot of pain in my joints. After taking Aromasin for 6 years I had develop Parkinson’s and my doctor decide to cancel the Aromasin on 2009 because my Neurology think that what have create my Parkinson’s is the Aromasin pill . Now I have been with the Parkinson’s since 2007 and I am with dissabily retirement because of the tremors on my left side.
Comment by Robin on 14 May 2010:
I have been taking tamoxifen since Jan. 2008 and have noticed reduction in memory skills, i.e., losing the “right” word in conversation, short term memory recall.
Comment by Susan on 28 May 2010:
May be this explains why I now frequently misspell words. I was always at the top of my class in spelling when I was in school. Now I always have to use spell check. This started after taking tamoxifen.
Comment by Linda on 11 June 2010:
I also have memory loss of words , misspell words, Had my vitrious of both eyes detach, have had personality changes, and have had to stop work. I only took temoxifen for a year and stopped when the vitrous detachment occured,because my optomatrist told me only very old persons had this condition and i was 57 at the time not 84. The doctor told me that the tomoxifen would block the hormons from reaching my breast , he did not tell me that all hormone production would stop. I had not started menopause at the time. The hot flashes have been debilitating. Any one else out there with these problems.? Has there been a class action law suit.???
Comment by Linda on 1 July 2010:
Any one with information on the long term side effects of Tamoxifen please lets talk about it . Memory and Eye problems for me.
Comment by Mitch on 13 July 2010:
Elizabeth, I’m not sure what you’re taking Tamoxifen for but I’ve tried it 3 times now for breast cancer & recently stopped it again bc of severe cognitive problems. I’m a grad student & need my brain at full capacity. On Tam. I feel like the village idiot. The alternative given by my onco (Lupron) is not tolerable for me either due to wild mood swings. I’m having to decide how important quality of life is to me. It seems to be a choice of increased chance of cancer reoccurence & feeling relatively normal vs. decreased chance & feeling crazy. If you’re an academic, the side effects can prove extremely difficult to live with.
Comment by Helene on 31 July 2010:
I too am experiencing terrible memory loss following tamoxifen. I can’t count the amount of times I said to my husband I think I’m starting with dementia. Im 55 years old and used tamoxifen for 3 1/2 years then quit due to the side effects. Sometimes I feel like I sound like an idiot. Simple words won’t come to me. There are days I could just cry out of frustration.
Comment by Diane on 4 August 2010:
I thought I was the only one with this problem of memory loss after starting tamoxifen. I have been on it for 3 years and feel my memory is getting worse. Hot flashes, depression, swelling, joint pain, but the one I hate the most is the memory loss. I just found this site but hope others post their reactions and any alternatives.
Comment by lynn on 20 August 2010:
Been on Tamoxifen for 2.5 years. Noted in past 6 months, an increasing inability to remember words (usually nouns/nasmes of objects). Also mood swings have worsened. “Flash” in anger over trivial incidents, followed by “emotional flatness.” My oncologist indicated (I see him in 5-6 months) that we will “talk” about the length of time I should stay on the drug. Fibve years, it seems, is not necessarily set in stone. ASK YOUR DOCTOR if you’re suffering cognitive loss.
Comment by wendy on 31 August 2010:
im permantly disabled. memory loss sezuires bone loss you name it i have had every bad side affect other than liver cancer!!!!