Hi, currently looking for answers to explain my symptoms. I have been on Letrozole for nearly 8 months and over the last three months have experienced multiple side effects from the long list attributed to this drug including shortness of breath to the point where I feel as though I may pass out. On 31st October I was blue-lighted into hospital with a rapid heart rate and was found to be very anaemic. I’m still in hospital, the medics are now looking for reasons for the anaemia but I can’t help wondering if the Letrozole is to blame for everything as I have a history of drug intolerance. Has anyone else been affected like this?
I have been on Letrozole since my diagnosis in April. The side effects have been dreadful. I had a check up with the oncologist after my radiotherapy and I told her about my issues. I am off it for four weeks then will start on Exemestane. The list of side effects are similar but I was told that we all react differently and it’s not unusual to try different variations of the drug. My issues are terrible hot flushes or shivers, trigger finger, terrible joint pain - I already have arthritis so that’s not great. I already have Atrial Fibrillation not related to the cancer meds and that has not worsened.
I do think the cancer treatment generally affects things like iron, vitamin B12 and vitamin D.
I get my first bone infusion in two weeks and a whole raft of blood tests have to be taken by my GP next week.
I do sympathise with you. I felt that the Letrozole was worse than surgery and radiotherapy! Yet a former workmate is also on it and is totally fine!
I really wanted to give up but my cancer surgeon said my tumours shrunk by 50% while I waited for surgery ( I needed heart scans and other tests on top of all the rest) . He says that shows the drug really works for me so I need to keep on with it!
Thanks for sharing your story. I had surgery in the middle of June and got hold of my pre-op assessment blood test results today. My iron readings were ok then so the anaemia has developed since surgery and radiotherapy. I have a routine appointment with the oncologist next week and will be asking for a break from the Letrozole and then a change in medication. Hope you get on well with your new meds.
Whatever cancer throws your way, we’re right there with you.
We’re here to provide physical, financial and emotional support.
© Macmillan Cancer Support 2025 © Macmillan Cancer Support, registered charity in England and Wales (261017), Scotland (SC039907) and the Isle of Man (604). Also operating in Northern Ireland. A company limited by guarantee, registered in England and Wales company number 2400969. Isle of Man company number 4694F. Registered office: 3rd Floor, Bronze Building, The Forge, 105 Sumner Street, London, SE1 9HZ. VAT no: 668265007