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Old 09-25-2016, 07:52 PM   #1
Teal55
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Aromatase Inhibitors: Personalized dosing?

Hi Ladies,

I was on ARIMIDEX for 6 months but had to stop last week due to side effects. My onco wants to switch to AROMASIN but I am holding off until I get a second opinion. I'm wondering if anyone of you know if these drugs are every compounded on an individual basis. I don't think I am able to tolerate the "standard dosage." Has anyone seen any studies that pertain to how the dosage is determined? Can you please share your experience regarding switching from one Aromatase to another. Arimidex to Aromasin
I don't understand how "one side pill" fits everyone? I am slender 118 lbs and finding it difficult to tolerate Arimidex. I'm scarred to try the steroid Aromasin. Please share your experience and any research you've come across.
How are dosages determined for patients?
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Old 09-25-2016, 11:12 PM   #2
donocco
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Re: Aromatase Inhibitors: Personalized dosing?

Teal

I'm sorry you are having these problems with Arimidex. if they are joint problems taking Vitamin D and getting a blood level of 66-70ng/ml might help.

As far as dosages go Arimidex(1mg/day) Letrozole (2.5mg/day) and Extramestane (Aromasin) 25mg /day are the standard dosage for each drug. As they are different molecules you cant compare the doses between them. The basic chemical structure of Aromasin is a steroid like estrogen. I believe the others have a molecule that consists of a pentagon made up of 4 nitrogen atoms and one carbon atom/

I am going to assume (dangerous word) that the "standard" dosage of each is that dosage that lowers the estrogen content sufficiently. So again I'm going to assume (dangerous word) that 1mg Arimidex=2.5mg Letrozole=25mg Aromisin.

Ill see what I can find tomorrow. Hope this helps a bit, particularly the Vitamin D part.

What you are talking about is potency. Potency is that dose of a drug that is effective. However a more potent drug is not more effective than a less potent one. You just need a lower dose ie 1mg Arimidex vs 25mg Aromisin

Paul
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Old 09-26-2016, 11:32 AM   #3
Teal55
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Re: Aromatase Inhibitors: Personalized dosing?

Thank You Paul for all the information.
If by chance you come across any data about proper dosage based on age, weight, size, BMI, ethnicity, PLEASE keep me posted! It just doesn't make sense to me how "one size fits all." Where is the data? I've seen studies as it applies to overweight/obese women. What about slim low BMI women?

I am going for a second opinion. I don't know if I'm going in circles, but I need to get more answers. My onc says there is no difference regarding dosage or between Arimidex and Aromasin, but what I read, and what you shared...there are differences....Isn't Aromasin a steroid? It's rebound is different as well etc... Arimidex has made me very achy and mentally depressed and down. Our brains and body needs some estrogen...

Where did you see the proper estrogen levels? Any data or articles you can send me? That's what I'm trying to find. The data.

Hope you are doing well. Are you a cancer patient or advocate for someone?

Thank you for your time and input!

Teal
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Old 09-26-2016, 11:36 AM   #4
Teal55
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Re: Aromatase Inhibitors: Personalized dosing?

I'm wondering, regarding Vit.D levels, can you send me information about this. This is making sense. I wonder why doctors don't recommend Vitamin D to help during hormonal treatment. My doctors don't.??? Thanks again!
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Old 09-26-2016, 12:59 PM   #5
donocco
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Re: Aromatase Inhibitors: Personalized dosing?

Teal

I learned a lot of this in pharmacy school and continuing education. Some info may be fuzzy. I should research before I say anything but using the puter is not what it was in the past. You focus on an article and literally minutes pass before you can scroll up or down as the many advertisements click on. This makes me a bit lazy. Not good.

The Vitamin D info is fresh. It seems that a blood level of the active vitamin D metabolite measured should be 65-70ng/ml. It may help with the joint pains caused by Aromatase Inhibitors and it might be valuable, along with appropriate oncology drugs to slow down the breast cancer. When they measure things like 10 year survival the women (99% of breast cancer patients are women) with the highest Vitamin D Blood levels do the best. Many doctors see a Vitamin D level of 30ng/ml as "normal" when it should be higher in patents with breast cancer. Some docs fear Vitamin D toxicity and hypercalcemia but the toxic blood level of Vitamin D is over 150ng/ml. Have your Vitamin D level checked. If it is below 66ng/ml, the doctor can prescribe the prescription Vitamin D 50,000 units once a week and after a few weeks check your level again. It it is still below 66mg/ml he could prescribe the drug 2 days per week, etc etc. Patients with rickets have been known to take over one million units Vitamin D daily.

As far as how low do you need the estrogen level to be brought down I think it is the same level of a woman in menopause. I don't know the specific number but will research it if you want to know. I assume you ovaries have been shut down. Usually they use a drug called Zoladex once a month. The Aromatase Inhibitors stop estrogen formation in the adrenal and fat tissue. I'm pretty sure the ovaries have to be shut down (or removed) before you can use Aromatase Inhibitors. If I'm wrong someone will jump in and say so.

Yes Aromasin (Extramestane) is a steroid compound. The body takes a weak Androgen called Androstenedione and makes it into a weak Estrogen called Estrone using the enzyme Aromatase. Since both Androstendione and Estrone are steroids it was thought that a steroid form Aromatase Inhibitor would be more effective than the non steroid ones like Femara (Letrozole)
and Arimidex (Anastrazole). Docs still use a lot of the non steroid Aromatase Inhibitors, particularly Femara so thde "steroid advantage" of Aromasin may be more theoretical than real. different patients respond differently to different drugs. I will research the idea of a lower dosage of aromatase inhibitor but my guess is you need the standard dosage to get the estrogen level down to a postmenpausal state. Well see.

Paul
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Old 09-26-2016, 01:25 PM   #6
donocco
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Re: Aromatase Inhibitors: Personalized dosing?

Teal
I checked up on Aromatase Inhibitor doses. For your own info go to Pub Med and type in doses of Aromatase Inhibitors . Look at the 4th article. They did an experiment. The standard dose of Letrozole is 2.5mg daily. So tjhey tried othr doses. One dose was 2.5mg letrozole only on Monday, Wednesday and Friday. The second dose was 1mg daily on Monday Wednesday and Friday, and the 3rd ose was 0.25mg daily on Monday Wednesday and Friday. Even the lowest dose was effective. Print out the article.

This was one experiment. I think its going to be quite a battle getting an oncologist to try this but you can show him (her ) the info and dicuss it.

Paul
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Old 09-27-2016, 07:07 AM   #7
Hopeful
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Re: Aromatase Inhibitors: Personalized dosing?

Trying to recall the name of an older thread on this board that dealt with a similar question, only it had to do with how quickly the body metabolizes a drug. As I recall it, for all drugs, there are fast metabolizers and slow metabolizers. There is a certain level of the drug that is supposed to be sustained in the body during treatment. The standard dosing for the drug is based on the clearance rate of the fastest metabolizers, in order to make sure that everyone who uses the drug gets the benefit they are supposed to from it. Unfortunately, the slower metabolizers wind up with a higher level of the drug in their body because they can't clear it as quickly. This may result in more prominent side effects from it. So, it is not just a body mass question but a metabolizing speed question to determine the optimum individual dosing.

Hopeful
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Old 09-27-2016, 10:02 AM   #8
donocco
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Re: Aromatase Inhibitors: Personalized dosing?

That's a good point. Ill check what enzyme primarily metabolizes each of the three Aromatase Inhibitors and see if there are large diffefrences from ethnic group to ethnic group and or (more important) from person to person.

A good example of an ethic diffefrence is acetylation. The antibuberculosis drug, Isoniazid
is acetylated and Asians tend to be slow Acetylators. Asians are more likely to experience toxicity with Isoniazid.

A good example of person to person difference is the Enzyme Thiopurine Methyltransferase. This enzyme changes the anti-leukemic drug, 6 Mercaptopurine into its active form. Those children (we are talking about Acute Lymphoblastic Leukemia) with a more active Thiopurine Methyltransferase system need lower doses of the 6-Mercaptopurine. "Normal" doses in the active Thiopurine Methyltransferase children are too high and there is a greater chance of bone marrow toxicity. This enzyme is now routinely tested on all Leukemic children getting 6-mercaptopurine as maintenance therapy.

Paul
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Old 10-18-2016, 12:41 PM   #9
Hopeful
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Re: Aromatase Inhibitors: Personalized dosing?

Saw this in one of the news forums and thought I would add it to the thread: http://www.medicalnewstoday.com/releases/313566.php

Hopeful
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Old 10-19-2016, 12:35 AM   #10
Teal55
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Re: Aromatase Inhibitors: Personalized dosing?

Thank you for all this valuable information. I stopped Arimadex for 1 month but 2 doctors said I should go on Aromasin. The doctor w the longest experience said o should go on tamoxifen for 2 yrs then switch. This has all been so frustrating. Bottom line I'm so afraid of all the short b love g term side effects. It's been non stop treatment. I've read about so many serious side effects from Tamoxifen.

Have you read about how a person's fear n doubt can influenence outcome? Poor outcome if you didn't trust the medicines. Interesting!

Let's keep this thread going. I'm all for personalize care n personalize medicine dosing as well. This is all valuable information. We need to continue to question n research. Thank you for sharing!
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Old 10-26-2016, 09:41 PM   #11
Teal55
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Als & brain damage?

I had a second and third opinion after stopping Arimidex for one month. Two of the three doctors suggested I switch to Aromasin. If side effects are too harsh they want to switch me to Tamoxifen. I started last Friday. Finger's crossed that I have no horrible side effects. Decided that if my "gut" says to stop again, I will listen. Realized at the end of the day, it's our bodies that are taking these drugs, not the doctors.

Thank you everyone for all your support and sharing information. If you come across anymore studies and information about Als impact on the brain please post. I know that it impacts more than just our bones.....

Wishing all of you good health!
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Old 10-27-2016, 02:36 PM   #12
Juls
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Re: Aromatase Inhibitors: Personalized dosing?

Hi Teal

Re Vit D

I think Vit D & Calcium should be taken even when not on AI's. There are some studies on pub med etc that actually recommend taking Vit D when on AI's particularly Femara.

https://www.ncbi.nlm.nih.gov
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