Tamoxifen and Mood Swings: What Users Say

• Jul...
• Taken for 6 months to 1 year
• February 25, 2019

For Breast Cancer "About 3 weeks after starting tamoxifen, I would wake up at night with night sweats and just insomnia. I noticed that I was definitely more hungry and craving junk food, which in turn caused me to gain about 5 pounds. I could have lived with these side effects, but then I started flying off the handle with my children at the drop of a hat. My reactions were crazy. I am normally generally mellow and easy-going. Then after about 4 months, I noticed I was having trouble focusing at work and was in a brain fog. It was mild at first but continued to progress to where I would fall asleep regularly at my desk. I decided for the sake of my new job (I am a widow and sole provider) that I needed to go off it for a while. After about 2 weeks, my life started returning to normal. I occasionally try to take it again, but then after a few weeks of starting it, the side effects return. I really wish more options were available to me to prevent the recurrence of breast cancer."

• Anonymous
• Taken for 5 to 10 years
• October 23, 2014

For Breast Cancer "I'm on my 6th year taking tamoxifen. I was on it for 5 years, and stopped - at that time it was thought I should only take it for 5 years. A year after being off and the new research came out that I should do it another 5 years. I've been back on now for about 6 months and I'm seriously considering stopping. Side effects are so bad that I'm having a hard time getting through life. Mood swings and bone pain are my 2 main issues. The thing is, I'm cancer free and of course want to stay that way. I think that if my doctors were more realistic (honest) about the side effects, it would be a little easier to deal with them. Reading some of the statements here is helpful actually - I feel a little less alone."

• 100...
• Taken for 2 to 5 years
• March 5, 2018

For Breast Cancer "I had breast cancer in 2004, ductal in situ, so I was very lucky. I had a breast removal, then radiation, and 5 years on tamoxifen. I was 48 at the time but very fit and had already gone through an early menopause, so the drug did give me symptoms, although I had not suffered any when going through the menopause. I had hot flushes, mild night sweats, mood swings, and put on a lot of weight! But it was all worth it to survive, and I soon got my figure back when I stopped it after 5 years. All I would say is treat these side effects as the menopause, and you will find they ease. Avoid spicy food, alcohol, and wear layers of clothes so when you get hot you can slip something off. Stay very active, my own weight gain happened when I slowed up my exercise. Also, I found sage tea very good for cooling down. Please, ladies, stick with it and stay well."

• Mai...
• Taken for less than 1 month
• October 2, 2019

For Breast Cancer, Prevention "Was prescribed 5 mg/day based on the recent Italian study that showed this dosage was equally effective as 20 mg/day, with side effects similar to placebo. Happy to report zero side effects after the first month. No mood swings, no hot flashes, no night sweats. I'm 57, postmenopausal, and only have had a few mild hot flashes ever before Tamoxifen."

• Anonymous
• March 19, 2014

For Breast Cancer "I'm 29, was diagnosed with breast cancer when I was 26. I have probably been on tamoxifen for a year. I have a hard time taking it regularly because of the side effects. The hot flashes are almost unbearable, my mood swings push people away, and my sex drive has decreased extensively. I am taking this medicine to prevent my cancer from returning. I have a 3-year-old boy that I live and breathe each day for, and the reason I will continue taking the medicine. But tamoxifen does make me miserable."

• Sil...
• Taken for 6 months to 1 year
• May 21, 2015

For Breast Cancer "I have male breast cancer. I do find it uncomfortable to only read about ladies' issues, but understandable. I have found that I feel depressed and have mood swings for sure. Upset tummy is common, so try to keep hydrated. I seem to get lethargic and tired around 3-5 pm, but I take my medication just before bed, 10-11 pm. I may consider changing this. Given the alternatives and worrying how my family would cope without me as the breadwinner makes the decision to continue to take it an easy one. I am not going to give in to it. I'm 59 and lost my brother to it aged 39. I played my first 70-minute game of tennis today in 14 months and really found it made a difference. So maybe keeping fit is one way of fighting back."

• tlc...
• September 1, 2010

For Breast Cancer "Though this medicine may give you a chance at living longer, the mood swings are massive. I feel depressed and have no energy. I am always nauseous. Everything hurts. My sex drive is basically gone, and my periods are slight if not altogether absent. I have shrunk inside a bit, so now sex is painful. I have hot flashes that keep me awake at night and make me very unhappy during the day."

• Ang...
• July 4, 2016

For Breast Cancer "It's one year I'm on Tamoxifen. I will manage all side effects that I have such as hot flashes, joint pain, back pain, mood swings. My goal is to live longer and see my son's future. I'm a 46-year-old. I try not to think about pain and side effects until I'm really tired from pain. The only thing I'm scared of is pain. The rest I will manage. Good luck to all of you! Life is beautiful, and fight for it."

• Anonymous
• March 4, 2010

For Breast Cancer "I have been on tamoxifen for 10 months now. I have had hot flashes, night sweats, mood swings, heavy menstrual bleeding, discharge, headaches, and now back pain. But I want to decrease my chance of possibly getting invasive breast cancer or DCIS in my other breast, so I will continue to take it."

• bas...
• August 10, 2015

For Breast Cancer, Prevention "I have been on Tamoxifen for 4 1/2 years. I have insomnia, mood swings, and other small side effects. I can't wait till my 5 years are up. I stayed on this pill because I want my risk of cancer to be low. My family has been very kind and patient with me. The worst side effect is cramping throughout my body."

• Bev...
• Taken for 1 to 6 months
• September 8, 2019

For Breast Cancer "Cancer Center of America told me to take tamoxifen with melatonin (20 mg). I take 10 mg both at night before I go to bed. It's been hard with the hot flashes and mood swings. It's been a month, and I'm trying to follow Dr. orders. Every day I want to stop taking it, but I don't. Say a prayer before taking it and pray for no side effects."

• jwi...
• Taken for 6 months to 1 year
• May 1, 2017

For Breast Cancer "I have been on Tamoxifen for about a year now. I have the hot flashes and the sweats, and oh yes, the mood swings, but now I'm experiencing severe temporomandibular joint pain (TMJ). I'm wondering if anyone else has experienced this problem on this medication. If so, what did you do to make it go away? Two weeks of this condition is two weeks too long. Any advice would be greatly appreciated. Thanks so much for any suggestions you may have."

• Ney...
• July 27, 2021

For Breast Cancer "I was diagnosed with breast cancer last year at the age of 32 and had my mastectomy on Oct 28, 2020. I began taking the tamoxifen in Feb this year (2021) and stopped after a few days. After visiting my oncologist, I realized how important it was that I continue with the medication. I’ve taken the medication consistently for two months, and within the months, I’ve experienced hot flashes, insomnia, leg pains, and mood swings that have interfered with my life. Counseling is a great help along with my support system. On top of this, I can’t begin freezing my eggs until after being on the medication for three years. There are a lot of sacrifices I have to make and realities that I have to face at now age 33. I want to live and will do what’s necessary to make sure that I give myself that chance to."

• Jen...
• Taken for 5 to 10 years
• October 29, 2021

For Breast Cancer "I am so happy to have found a forum about this drug. There aren't many blog groups about Tamoxifen, and I would love to bounce my side effects off of others. I am 44 years old, and I have been on Tamoxifen for almost two years. I feel like I am experiencing every side effect on the list. I was diagnosed with DCIS. After a lumpectomy and lymph node removal surgery, I underwent 25 rounds of radiation, and here I am for a recommended 5 years' worth. I have been experiencing shortness of breath, lightheadedness, severe mood swings (like 0-60 in seconds), discharge comes and goes. Some days it is worse than others. I was having severe night sweats in the very beginning, but when I told my doctor about it, she suggested I take a 2-week break to 'reset' my system. After the 2-week break, I went back on the Tamoxifen, and the night sweats were a lot less! Even if I have to throw the covers off a little bit, I sleep a lot better now than I did."

• SCM...
• Taken for 5 to 10 years
• April 17, 2025

For Breast Cancer "I have been on tamoxifen for a year and a half and have found that once I stay active and eat mostly whole foods the side effects are minimal or none at all. I have had instances where I'm unable to exercise for a few days and the mood swings, fatigue, and hot flashes hit me like a stack of bricks. Once I'm able to find the energy to start exercising again, the side effects usually go away."