Yes however mine informed me to take Claritin and my head felt better !

There are definitely some changes. Depending on how far past menopause, and what level of estrogen is still in your body at the time you start tamoxifen can make a difference. For me, at 67 with fairly low estrogen levels and 17 years after menopause, I could feel my body making adjustments. The first week I had some warm flashes and moodiness and feeling “off”. That increased at week 3 - that’s about the time the full affect of the tamoxifen is in your body because of the 7-10 day half life of tamoxifen. The drug accumulates every day until it evens off. I pretty much quit having regular warm flashes and the moodiness evened out. At 3 months I felt more changes - I think by this time all the body’s organs and functioning has adjusted to the tamoxifen, and it affects parts differently.
I’d suggest waiting to see how it goes, manage the things that you can (headache), give yourself some grace to deal with the mood changes, and see how your body adjusts. Unless of course there is a really bad issue, then the doctor needs to know. Our bodies are all different, it’s hard to know exactly what side effects you’ll have.

I have been on Tamoxifen 5mg daily now for about 4 months I couldn’t tolerate 20 or 10 mg Changed manufacture and reduced dosage to 5 mg I started to experience heartburn no relief with Tums Oncologist said to try Prevacid It did stop
the heartburn in one week but on day 8 nonstop diarrhea
So quit taking wondering if anyone has had insomnia and really crazy dreams with this low dose this has been happening recently along with some anxiety and I have always had a good memory even at my age but lately can’t find the word searching for in a conversation Yesterday stopped for a cup of coffee and a donut couldn’t remember name of donut I always get, had to describe it
The hot flashes are less and so is the joint pain of course aging skin, well I’m 82 now just had a birthday Of course getting up multiple times a night to urinate is still present
Sorry such a long story wanted to try to give the total picture Thank you for any input
Sally in CA

I had such a terrible time with Anastrozole that I took nothing for a full 9 months. Then, on the one-year anniversary of my lumpectomy, I paid out-of-pocket for a HerScan ultrasound here in Texas where we winter and it did not go well. I was sent for a diagnostic mammogram and they wanted to do a stereotactic biopsy. I had a stereotactic biopsy in 2018 and it was extremely painful and took months to heal. I had a second biopsy on Dec. 7, 2021 that found the 11 mm. tumor, but it was NOT a stereotactic biopsy. The needle used looked like a pig's curly tail and it was far easier on me. I also knew that they could gather all of my annual mammograms to see if there had been any changes from mammogram to mammogram, and I held out for that, which took a while, but did not involve plunging a 3-foot long needle into my right breast. (There is still calcification on both sides.) My new Texas oncologist went to war to get the oncotype I should have had back at the beginning, which my Illinois oncologist refused to order, saying simply, 'You don't need one." At that time, I knew so little about b.c. that I thought HE was the expert and certainly would do what was in my best interest(s), but I did not know that he had a reputation for never ordering anything expensive that might get him into trouble with Medicare. ("He doesn't want to get dinged by Medicare.") So, no oncotype for me, even though they have been standard of care since 2013. When my Texas oncologist got me the oncotype, in the spring of 2023, 17 months had passed and my score was 29, which is NOT a "good" score. (36% chance of a recurrence without 5 years on Tamoxifen; 18% chance of you take Tamoxifen for 5 years.) So, I agreed to begin taking Tamoxifen, but I told my Texas oncologist, honestly, that I had had such a bad experience on Anastrozole (crippled me and put me in a wheelchair for 6 months, among other side effects) that I would tip-toe into the Tamoxifen waters taking only 10 mg. And, on top of that, after reading about the half life, I took 10 mg. only every other day, for a grand total of 40 mg. weekly, versus the 140 that I was told I should be taking. For 2 months, in effect (April 23, 2023 to June 23, 2023) I was on 5 mg. daily. The biggest thing I noticed was that I had to pee ALL the time! I am a Type II diabetic, as well, and with these 2 diseases I spent every moment making sure a bathroom was nearby. Everything below the waist felt dry and itchy. But I was handling it fairly well until my Texas oncologist called me up on June 23 and said that the Italian Women's Study of 700 women that took a "BabyTam" dosage was comparing apples to oranges, as their tumors were in situ and mine had broken through. He said that the only clinical evidence of efficacy they had was for 20 mg. and I should move up to that dosage ASAP, which I did. So, from June 23 until Aug. 30 (2023) I took 20 mg. On 20 mg. I could not stay up for more than 3 hours. I had extreme fatigue and no amount of sleep alleviated it. (We were supposed to go floating down a river here in Texas in inner tubes, but it took 3 and 1/2 hours, and I would have probably been at the bottom of that river if I had attempted to joint the family reunion group that made that trek.) I then started getting UTIs and the worst one was right before New Year's Eve. Nothing in my normal arsenal of meds touched it. I took Amoxicillin. Nothing. I was given another strong antibiotic (started with the letter "N") and nothing. I suffered with the itchiness and discomfort that a UTI brings with it for over 2 weeks and finally had to throw myself on the mercy of my oncologist and go in, in person. They got the UTI under control, but the strong antibiotic left me with a fungal infection which required ANOTHER medication. Bloodwork was done, and the bloodwork done on March 7, 2023, which had been fine, was now, on Aug. 30, 2023, after 5 months on Tamoxifen, was not fine. Ten (10) things were "off" and the fatigue and itchiness and dryness and discomfort and constant nagging urge to urinate were all part and parcel of the experience. I went off everything on Aug. 30, 2023. Of course I am apprehensive about not taking anything, with the onco score of 29 and a 95% estrogen positive tumor, but I'm 78 years old (79 in July). While I don't doubt that the "clinical evidence" says you have to take 20 mg., there are so few women in their 70s even IN those studies that I question whether it wouldn't have been a better idea to have let me struggle along on the 10 mg. every other day (or 5 mg. daily). As it is, I quit everything and am concerned about finding a good test to keep track of some spread. There don't seem to be any until you experience symptoms of the cancer having spread, which is not encouraging. I've asked about the C-27 or whatever it is and the Signaterra and I have had mammograms every 6 months (although my Texas oncologist said, "I'm not worried about it coming back in your breast; I'm worried about it going somewhere else." So am I, but what are my options? I cannot tolerate A.I.'s and should never have been put on them, as I was an over 20 year participant in a study for people with a strong family history of arthritis and damaged joints. Anastrozole crippled me and my left knee will never be 'right' again. It also gave me excruciating joint pain (actually had to have shots in my left knee and Tramadol for pain), brain fog, blurry vision from dry eyes, dry skin, teariness, mood swings, insomnia and vivid violent nightmares. Two doctors here in Texas have told me I should never have been put on A.I. drugs with my well-documented over 20 year history in the MOST study and I believe them. So, that leaves Tamoxifen, and on 20 mg. of that I cannot function and face serious consequences from UTIs run amok. One of "Charlie's Angels" (Tonya somebody) died from a UTI infection at the age of 62 and she was an athlete and a runner, plus my best friend Nelson Peterson died from a UTI infection, the result of cancer that left him dependent on a colostomy bag and, subsequently, he had repeated UTIs and was hospitalized for same many times. If anyone knows of a test that will "track" cancer in our bodies (beyond the annual mammogram) please share that information. I need "protection" from the drugs we have been told will "protect" us and I can't see spending my last couple (hopefully) decades of life crippled and uncomfortable and laid up with excruciating bone and joint pain and/or extreme fatigue, on the off chance it might prevent the universally dreaded recurrence. I would really like to get into one of the studies now ongoing to find errant cancer cells in our survivors' bodies and stomp them out.