I have changed from letrozole to exemestane as I could not tolerate the side effects of letrozole the worst being depression and brain fog along with joint pain. 

Exemestane is causing less joint pain but I am suffering from nausea and constipation

 The oncologist has given me anti nausea tabs which help but can make you feel tired. I really dont want to end up on a cocktail of drugs. Another oncologist said they call it pharasoup.

I am going to give it a go as having had breast cancer twice on the same side even though I had a mastectomy I feel it is wise.

I will see how it goes.

I hope you manage to recreate the new drug.