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Femara and Brain Fog: What Users Say

Brain fog: mentioned by 7 users (10.4%)

Based on user experiences from 67 Femara reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

joint pain 44.8%
hot flashes 22.4%
hair loss 19.4%
pain 19.4%
muscle pain 11.9%
brain fog 10.4%
weight gain 10.4%
bone pain 9.0%
fatigue 7.5%
night sweats 7.5%

Reviews for Femara

Commonly mentioned side effects
  • Chi...
  • Taken for 1 to 6 months
  • January 26, 2015

For Breast Cancer "Had Grade A Breast Cancer that was caught early. Had a mass and one lymph node removed. Went on Femara on Nov. 8, 2014, the day after I finished radiation. At first, I didn't notice anything. Slowly the pain in my feet started, then other joints in my body. I felt like I was having trouble getting air into my lungs. I started feeling like I was in a fog. I already had been diagnosed with depression years ago which was under control with medication. I started experiencing depression a couple of weeks ago which included waking up and crying. That turned into suicidal depression. Without pain medication, I couldn't move around well. The bottom of my feet were killing me. I work full time. I quit the Femara 2 days ago."

1 / 10
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220 Report
  • tin...
  • Taken for 6 months to 1 year
  • April 29, 2023

For Breast Cancer "Awful! I've been on Femara for about 8 months. And since I started, I seem to have every single side effect. My joint and muscle pain is excruciating. In no particular order, I suffer with body pain (fingers, hands, shoulders, chest, back, sides, hips, legs, feet - basically everything head to toe). Plus, weight loss, hot flashes, headaches, dizziness, thinning of hair, dry mouth, high BP, night sweats. Even my scalp is tender. Chest pain that radiates to upper arms, shortness of breath, overall depression. Chills, insomnia, intestinal pain - sharp pains, plus dull aching. Constant feelings of nausea, diarrhea, constipation. I'm afraid to eat but also have little appetite. Brain fog, shortness of breath. Feeling that I am just going to die. Sitting up in pain all night. I hurt everywhere - too sick to move; too sick to cry. Feels like I am going to have a heart attack. Can’t lie down, can’t stand up. Full body chills, hands shaking. Haven't slept through the night in months."

1 / 10
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46 Report
  • dog...
  • Taken for 2 to 5 years
  • July 19, 2014

For Breast Cancer, Adjuvant "I was diagnosed in 2009, had lumpectomy, chemo, radiation. Managed to continue working through it all. Then took tamoxifen for 2 1/2 years... had horrible muscle cramping and hot flashes, switched to letrozole after determining I was postmenopausal. The major muscle cramps lessened considerably, as did the hot flashes. I took this for 2 1/2 years, just stopping 3 weeks ago. I have muscle, joint, bone achiness 24/7, no energy, tired always, feel like I'm in a fog, tinnitus, heartburn, slow metabolism with weight gain. How long will it take to reverse all of these side effects now that I no longer take it? I even quit taking ibuprofen because it doesn't do anything for the pains. I am now 2 months from being 50 years old."

5 / 10
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141 Report

Frequently asked questions

  • min...
  • September 12, 2015

For Breast Cancer "In 2011, I was diagnosed with stage 3A invasive ductal breast cancer. I went through chemo for 4 months and had a double mastectomy in March 2012, followed by 6 weeks of radiation. I was put on tamoxifen for a year and then Femara, which I currently take now. The biggest thing with Femara is feeling constantly tired and 'foggy'. I can handle the hot flashes (we live in Minnesota, where the winter lasts for 6 months) - I just walk around outside with a t-shirt on, and I'm good to go! Lately, I have been experiencing hair loss, and I don't know if it's due to the Femara. Anyone else have this problem? Please let me know. Hang in there, beautiful ladies (& men)."

7 / 10
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96 Report
  • apr...
  • March 21, 2016

For Breast Cancer "I have been on this drug for about 3.5 months now. I was on Aromasin (exemestane) for 2.5 years prior to starting letrozole. I was so hopeful that some of the horrible side effects would not affect me like they did on the exemestane...and for a while, it was not too bad. Now, in month 3, the side effects of severe joint pain, brain fog, and shortness of breath are back with a vengeance, and the last 3 times my blood pressure was taken, it was inching back up even though I started BP meds after the exemestane raised my BP. I never had any issues with my BP prior to taking these aromatase inhibitors. I guess my PCP will have to raise my dose of BP meds. I am also peeing constantly on letrozole, and my hair is coming out more on my brush! UGH!"

2 / 10
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90 Report

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  • Con...
  • Taken for 1 to 2 years
  • July 9, 2021

For Breast Cancer "Male had breast cancer removed. Lymph nodes clear, but started on this after I had a bad MRI for an eye issue. Started taking letrozole as insurance. Recently have been having more brain fog, unexplained black eye, yellow bruises on legs, and one on my arm. Will probably stop taking. Also just diagnosed with glaucoma like someone else here. Good luck. It seems this drug works for many, and doesn't fit for a lot too. Make up your own mind for what is best for you. Good luck."

3 / 10
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14 Report
  • jki...
  • November 30, 2010

For Breast Cancer, Metastatic "Had to get off of this. I still work and could not get past the 'brain fog' and severe joint pain."

1 / 10
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107 Report

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Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.