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Best time to take Arimidex--morning or evening??

tami48 Member Posts: 270

I'm starting Arimidex either tonight or tomorrow morning.  I'm just not sure which would be the best time.  I'm worried if I take it tonight that it may interfere with sleep--- am having problems sleeping as it is.  Then I wonder if I take it in the mornings will it mess up my whole day. 

Any ideas, ladies?  What time of day do you take it?  Any problems or difference with taking it am or pm?



  • Trish03
    Trish03 Member Posts: 65

    I take mine at night, and it doesn't seem to affect my sleep. At first, I took it in the morning, and I often had diarrhea. That changed when I switched to night.

    All the best to you,


  • candie1971
    candie1971 Member Posts: 2,467

    I take mine in the morning and have been since I started 18 months ago. I take it along with my bood pressure pill. So far, so good.

    I wish you the best,also,


  • tami48
    tami48 Member Posts: 270

    I took my first pill this morning.  If it bothers me alot then I'll try taking it at night.


  • otter
    otter Member Posts: 757

    tym, I don't think it matters what time of day you take your Arimidex pill.

    According to the package insert, you can take it with or without food; and there is nothing I saw to indicate that it should be taken in the morning vs. evening.  I have been on Arimidex for about 2-1/2 weeks, and I take mine at lunch plus or minus an hour or so.  It's just easier for me that way, because I have another unrelated med I need to take first thing in the morning on an empty stomach, and some others I take in the evening right before bedtime.

    Arimidex has been on the market, or at least in testing, for quite a few years now, so there actually is a lot of information available about it.  For example, according to the clinical pharmacology info on, once you start taking Arimidex on a daily basis (1 mg per day), it takes about 6 days for the concentration of the drug in your blood to level off.  If you continue to take it daily after that, the concentration of the drug in your blood doesn't fluctuate very much during the day or from day-to-day. 

    Arimidex stays in your body for quite awhile after you take the pill--the half-life of the drug is 50 hours.  That means once you take the pill and the drug enters your bloodstream, it takes more than 2 days for the concentration of drug in your blood to go down by 50%.  At that rate, it would take 5 half-lives, or 10 days, for most of the drug (97%) to be excreted from the body.  When the half-life of a drug is that long, changing the time you take the drug by a few hours would have very little effect on the blood levels once the steady-state is reached.

    What's really important is what Arimidex is doing to our estrogen (estradiol) levels.  The amount of estradiol in post-menopausal women is low anyway, and Arimidex will cause it to drop to an almost undetectable level.  Arimidex affects estrogen synthesis pretty quickly.  Just 24 hours after taking your Arimidex pill, the amount of estrogen (estradiol) being synthesized by your body will have decreased by 70%.  However, once you've been taking Arimidex for more than a few days and its concentration has stabilized, if you stop taking it suddenly, your body won't begin making estrogen again for about a week.

    I have heard women on these boards say Arimidex interferes with their sleep or upsets their stomach.  I'm glad to say I haven't had any problems from it, so far.  I realize it is still early, and some of the more serious SE's like joint pain and certainly the bone thinning, take awhile to develop.


  • tami48
    tami48 Member Posts: 270

    Otter, thanks for all the info.  Sounds as if you've been reading up on this.  I'm glad you haven't had any problems--hopefully you won't!  

    I'm not sure how long it should take before I know if the Arimidex works okay with me.  My Onco gave me a 28 day supply, so I'm thinking I'll know within 4 weeks. 

  • akjs19
    akjs19 Member Posts: 2
    This is my first time on this sight and I already got the answers for my questions. I have been on Arimidex for about four months. I am tired, have joint pain, and just feel a lot older than I am. I was wondering if the time that I take the medication would affect the side effects. From the answers that I read, I guess that it does not matter. It just surprises me that some days are worse than others. Does anyone have the same results or anyone know why?? I was on three different medications nine years ago. I was fine on two of them, but Aromasin made me feel the same way. I continued for seven and a half years and then stopped. One year later, I had a new breast cancer on the other side. I am thinking of stopping the Arimidex, but of course, I do not get much support for that decision. Anyone feel the same or have any thoughts on what to do?  Thanks for reading this and I hope to get some 'sisterly' advice.
  • krisbee1
    krisbee1 Member Posts: 1

    I am terrified to take the Arimidex due to all the side effects.  I was diagnosed in April for the 2nd time with Stage II cancer, no lymph node involvement and had a masectomy.  The last time I had breast cancer, in the same breast, was 26 yrs ago at a Stage I and had a lumpectomy and radiation.  I have never had to have chemo.  I have extreme sensitivity to all drugs and I am not sure that this pill does more good than bad?  Has anyone taken it for the full 5 yrs and not had a recurrence for a least 5 yrs?

  • figgy652
    figgy652 Member Posts: 5

    HI,  I have been taking Arimidex for about 5 months.  I am also very sensitive to drugs. It's a curse, really.  I had a difficult time in the beginning.  I didn't feel well, I was very tired, I wasn't sleeping well and I had didn't have a good attitude about taking it.  I went to see my doctor and told him I just couldn't hack it.  He told me to give it awhile longer and then go off if I needed to.  Low and behold during the 3rd month I started to feel much better.  I was also very resistant to taking the drug.  I really didn't commit to it in my mind and kept thinking I was going off.  I didn't like the idea of every bit of estorgen in my body being supressed.  I think it was really difficult for me to adjust physically and mentally to Arimidex but I have adjusted and feel fine.  Give it a go...and think of me if you have trouble and how I told myself everyday I was going to go off.  

    I do also think I read too much in the discussions from women who had a terrible time with Arimidex for a variety of reasons.  I finally realized the women on the discussion were, of course, the ones having the most trouble. Many, many women take this drug very sucessfully and they are not on the discussion boards. I feel very sympathetic to all those struggling with aromatase inhibitors.  Some have really significant joint pain etc . I was able to overcome my fear and the intial side effects.  Good Luck! Hang in there.

  • akjs19
    akjs19 Member Posts: 2
    I finally remembered to come back to this site and see if there were any responses. The last post was very encouraging and helpful. Today happened to be a great day. I think that the way you described the idea of going off it making you feel better is true. I know that I should stay on it and I think that I have to change my thinking. One of my doctors told me to stay on it forever!!! That did not sit too well with me. But, we will see. Thanks for your feedback.
  • Kheng
    Kheng Member Posts: 11

    Dear skjs 19

    ******Your doctor's advice is of goodwill

     If you Google "the optimistic traveller", you will learn that this 65  yrs old lady is taking Arimidex for 10 years with no side effects

     She is stage 3, grade 3, about 18 lymph nodes infected but she is happily travelling on holidays

     I felt tired and suffering from fatigue every now and then

    Depression follows behind fatigue as they are twins

    It is not just due to Arimidex but due to the invasive chemotherapy and radiotherapy

    I stopped taking lexapro after 3 months, as I do not want to be addicted

     I consulted traditional Chinese medical oncologist, and takes the herbal tea daily to calm my nerves and to helps blood circulation as my 18 lymph nodes has been removed

     Over - suppression of estrogen can cause nervousness, fatigue, joint pains, etc

     Never give up, I learn from this forum, then I requested my oncologist to prescribe 1000 mg of vitamin D3 and 600 mg calcium caltrate plus glucosamine

     The bone pain and triggered fingers disappears after I take glucosamine, vitamin D3 with calcium caltrate

     Arimidex cause loss of appetite and weight loss as I am 5 kg below BMI 

     This September 19, is my two years on Arimidex, I just learn to take vitamin B complex after breakfast with Ester-C

     Upon waking up, I will take one tablespoon of barley green with 1 dessert spoon of black strap molasses and 1 lemon juice, then add filtered boiled water to 500 ml, then drink slowly with a straw

    Will go for power walk or an hour of "Praise and Joy Dance" in the park about 3 times a week

    At times, I forget to take Arimidex but I knew that this drug remains in our bloodstream for 2 days therefore when I feel depressed then will stop the medicine temporary and go to wellness centre for 5 days 

    My blood works at the wellness centre show that I am well except that my blood cells need vitamin B complex

    Anybody worries about side effects should start to exercise and take health supplements

     I take 2 capsules of cracked spores lingzhi half an hour to an hour before dinner

    If you feel depressed and loss of motivation, quickly take vitamin B complex with Ester-C or go to wellness centre for 10 days

    Do not give up as Arimidex gives HOPE

    Last year, 26 October, I lost my aunt (Lung cancer)

    This year, 20 January, I lost my youngest brother (Lung cancer)

    Any medicine with side effects is always better than no medicine as side effects can be overcome by herbs and health supplements

     Read Jeremiah 33:6

    John 7:37-38


     Listen to your body, when tired, rest and sleep 

     Life after such invasive barbaric medical treatments, makes a difference like a caterpillar be transformed into a butterfly

     Do learn to enjoy and exercise when your energy level is high and quickly rush to bed when you feel tired, just lie on bed and closed your eyes to talk to God even if you could not sleep

    It is time for me to go for power walk, then cook dinner 

    Every meal must have carbohydrates, protein and vegetables

     Will take Omega 3 after dinner and 20 types of brewed herbal medicine

     I take Arimidex during bedtime as our estradiol is high while we sleep

    Take care of yourself and pray for God's love and wisdom

  • Rosemoongarden
    Rosemoongarden Member Posts: 1

    I was taking Arimidex in the morning. It was hard for me to remember if I had taken it, had anxiety that was increasing, and was having

    periods of depression, which occasionally sort of lifted. Now I take it at night, and I think I sleep through all the bad feelings. The diarrhea has improved.

    Have only been taking it in the evening for a week, so I hope this continues.


  • Having_Faith
    Having_Faith Member Posts: 6

    Thank you for all the information. I start Arimidex this week and have been a little nervous due to all the side effects i keep hearing about.

  • Having_Faith
    Having_Faith Member Posts: 6

    Thank you for your inspiring story.

  • muska
    muska Member Posts: 224

    I don't think timing of arimidex matters. I would just pick a time of day that fits your routine so that you don't forget taking it. If you take other meds in the morning I would take it in the morning. If you take your meds at night and nothing in the morning I would do it at night.

    Since I only take arimidex and vit D3 it is much easier for me to swallow it in the morning and be done with it.

  • Alaskaraven
    Alaskaraven Member Posts: 1

    After a scary bout of dizziness, my pharmacist told me to stay well hydrated and not let myself get too hungry between meals to even out metabolism and minimize side affects of arimidex. This seems to help the swings in side affects I was experiencing. That as well as a concerted effort to eat healthy foods. Maybe this will help you too? Best wishes

  • denise-g
    denise-g Member Posts: 353

    I switched to nighttime because of dizziness with Arimidex. It helped. If I don't drink enough water, I feel it.

    Thanks for your post!

  • justmetoo
    justmetoo Member Posts: 4

    Today is my 7th day on Arimidex and I had a bout with dizziness, wondering if taking it at night helped those who had dizzy spells, and what causes the dizziness

  • 4happygirl
    4happygirl Member Posts: 9

    I started off taking it in the morning. Then he joint pain started, and the swelling and pain seemed worst around 6 hours after I took the med. So, I started taking it at night so I would be off my feet for the first 7 hours of it. It made night sweats worse when I took it at night, so I would also take an ibuprofen to counteract the swelling and keep me asleep through the night sweats. You'll just have to experiment and see which time of day is the most comfortable for you depending on if you have SEs and which ones you have.