I developed carpal tunnel in both hands and trigger thumbs after taking letrozole for only 4 months. My oncologist suggested a break, so I have been off it since early May. I used a system called the Carpal Solution to help with the Carpal tunnel. It is much better, but not completely resolved. My hands still go numb, but the thumbs have not improved. I'm going to try some kinesiology tape and I'm taking one tablespoon of apple cider vinegar in water once a day and 50mg of Vitamin B6 (P-5-P) twice a day to see if it will resolve. All suggestions I found on the internet. I'm also doing lots of exercises and PT. It's very painful and keeps me from doing all the things I love to do.