Aromatase Inhibitors: How to choose and manage side effects?

Yes - the side effects of some of our best cancer medications are really no fun. I'm taking anastrozole and have found walking for 30min+ each day really helps for joint pain (motion is lotion!) as well as my overall fitness and mental health. I also do acupuncture which helps with joint pain and hot flashes. I began drinking a basic bagged melatonin tea that you can buy at the grocery store at night to help me fall sleep and then learned from my physician that it's actually the catnip in the tea that is helping with sleep. I swear by it. I trust my oncology team's expertise and I also look at medical studies on my own and bring questions when I have them. While our diagnoses can be similar, each patient is unique in how their body reacts to the medication, tolerance to side effects and varied quality/length-of-life perspectives. I wish you the best in finding what works best for you.

I just had lumpectomy last week 1.2 cm stage 1 no lymph nodes no margins!
E&P positive - her2-neg I have decided on 5 day radiation with No hormone receptor pills
2025!!! Should have much better options with less side effects.

I am on Letrozole and at first I had a dull headache for about a week. That went away but now I am having joint pain and sometimes when I eat, things taste like soap. I had to play around with when I took it as well as when I took it at night, I couldn't sleep. I take it now at noon.

I started AIs in Dec 2024. First was Letrozole--gave me terrible tinnitus, then Exemestane, again terrible tinnitus. Med. Onco. suggested taking Exemestane every other day, but that didn't help much. Switched to Anastrozole in March 2025. No problems at all. I never tried Taxomifen. I have no idea why I got along with Anastrozle, but not with the other two. Also there's Fulvestrant, but it's injectable (not a pill)--never tried it.

Also, Anastrozole seems to disturb my sleep, so I take it in the morning. I also take Kisqali (ribociclib--not an AI, but a CDK4/6 inhibitor because I have a fairly aggressive cancer) which seems to make me tired, so I take it at night.

My advice: don't give up on AIs until you've tried them all. Also see if morning dosing or night works better for you.

After 24 years “cancer free”, I developed a rather large lump that was ignored for well over a year but was finally acknowledged after seeing Ob/Gyn for endometriosis (at age 78 following MRI when hospitalized w/pneumonia). I was sent through a battery of tests/scans/biopsy and found great oncologist/surgeon. I am taking letrozole also without any problems thus far (2mos.) Important to get doctor/oncoligist/surgeon you are comfortable with. I was initially told I would need mastectomy but am now going to have lumpectomy once tumor shrinks from taking letrozole, in 6-9 months. Wishing you a healthy outcome and proper guidance for treatment!

I have been on them for 5 years.................that's long enough!

From what I've seen, there is really no way to tell in advance which aromatase inhibitor will have the fewest side effects for you personally. Your oncologist will probably start off with the one best suited to fight your cancer. You can take it from there. I suggest trying it, and if it is intolerable, discuss again and try a different one. I think you have at least a fifty percent chance of doing ok with the first one. I was given letrozole 2 1/2 years ago and have had no side effects. My bone density remains normal. I went in with stage 3B kidney disease, and that is stable. Hope all goes well for you, and that you can go forward with ease.

My first oncology appointment is in 3 weeks but I wanted to get information from women who have been on different hormone blockers so I can make an educated decision about what, if any, blocker that might work best for me with little side affects. Thank you for your feedback.

I moved your question to this related existing discussion where you can connect with others who faced a similar decision:
- Aromatase Inhibitors: How to choose and manage side effects https://connect.mayoclinic.org/discussion/ai-inhibitors/

@clemonsmjn1, you're asking good questions and ultimately the decision is yours to make with your oncologist and kidney specialist. The more information you have specific to your risk factors and related health conditions, the more tailored the answer will be to you and your situation. Of course, your personal preferences are also come into the informed decision making.

Like @celestebradham says, some people have no side effects or some side effects that can be managed. And there are several different hormone blockers to choose from. While one may cause side effects that negatively affect quality of life, another type may not. It's good to keep in mind that forums like this one can make it appear that side effects affect everyone. That is because the women who experience side effects often seek tips and support to help manage the side effects.

It's not an easy decision. @clemonsmjn1 have you talked to oncologist or oncology pharmacist to find out about any drug impact on your kidneys?

Thank you for your comment and details. It’s helpful to hear of what others decide and the experience. I appreciate your feedback.
Blessings to you.