Letrozole and radiotherapy

I started my course of Letrozole 3 days ago. My surgery was 4 weeks ago and I have recovered well and apart from the first few days have not felt tired or poorly at all. Since I started the Letrozole though I have felt completely wiped out. It suddenly hits me like a wall half way through the day. I did go for my Radiotherapy planning session yesterday so not sure if that could have contributed to the tiredness although all I did was went in and out the scanning machine. 

has anyone else had this side effect from Letrozole? If so how long can I expect it to last. 

Hi Wendy . I’m the same 3 months in…keep telling myself it’s the after effects of chemo and rads as well…my Onc said give it 6 months for side effects to settle down and what you are left with is what it will be… for me, it doesn’t seem worth changing brands because of fatigue when Im Not getting other side effects…but I may change my mind later down the line.  Sorry I’ve nothing helpful to add.   I finished my rads in February and they did cause noticeable fatigue so it may be a bit difficult to see which is rads side effects and which is letrozole, for a bit.  

hope your radiotherapy goes well

Just a follow up from the other replies. 

I began Letrozole in January and started Radiotherapy in February.  I can’t say I was any more tired when I began the Letrozole.  It was during and after the RT that I got very tired and can say I am still getting tiredness some days.  Like yesterday I met a friend for a walk and chat, and had a lie down later that afternoon and then this morning I was not out of bed before 10.00am.  I do take my Letrozole in the evening now and this has stopped any hot flushes I had been experiencing.  But I can say the RT tiredness continues for a very long time after treatment finishes.