Tykerb and weight gain

[Basilic]

I am on Tykerb/Herceptin combo for neo-adjuvent therapy. I have gained several pounds since starting treatment, but recently discovered that my TSH was very elevated. I think that the Tykerb might have been blocking some of my levoxyl as I was taking them together on an empty stomach. My endocrinologist agreed with me and we raised my levoxyl up a little to counteract it. Not even 3 weeks into the adjustment, my weight was down for the first time since January. Also my fatigue wasn't as pronounced. I had been blaiming everything on the treatment, but more likely it was low functioning thyroid in my case.