Sleep problems and night sweats on endocrine therapy

Tamoxifen and aromatase inhibitors lower oestrogen or block its effects. That affects the brain's temperature control, triggering hot flushes and drenching sweats, often at night. Each episode can wake you, and repeated waking leads to broken, unrefreshing sleep. Joint pain, needing to pass urine, worry about the cancer and low mood can make sleep worse still. Poor sleep then feeds tiredness, irritability and difficulty concentrating during the day. The good news is that sleep problems on hormone therapy are very treatable with practical changes, talking therapies and, for some women, medicines.

Why sleep deserves attention

Good sleep supports mood, memory, energy, weight and the ability to keep taking hormone therapy. Many women who stop their tablets early mention exhaustion from poor sleep as part of the reason.

What helps most

Keeping the bedroom cool, reducing triggers, a regular sleep routine and cognitive behavioural therapy for insomnia have good evidence. Medicines that reduce night sweats, such as gabapentin or venlafaxine, help some women.

When night sweats need checking

Sweats with fever, unexplained weight loss, a new cough or feeling unwell should be reported, as infection or other causes need to be ruled out.

Most women can reduce night sweats and improve sleep noticeably, though it may take several changes working together, and a few weeks, to see the full benefit.

Sleeping tablets are not a long-term fix

Traditional sleeping tablets can cause dependence, daytime drowsiness and falls, and they do not treat night sweats. They are usually used only briefly, if at all.

Talking therapy works well

Cognitive behavioural therapy for insomnia has strong evidence in cancer survivors. Its effects often last longer than medicines, because it changes habits and thoughts that keep insomnia going.

Some medicines need care with tamoxifen

Certain antidepressants used for flushes can weaken tamoxifen. Your team will choose options that are safe with your treatment.

What this page cannot tell you

It cannot tell you why your own sleep is poor. Ask your team to look at all the possible causes, including pain, mood and other medicines.

A run of disturbed nights can leave you exhausted. Managing the day well also helps the next night's sleep.

Stay active

Even when tired, a walk in daylight improves energy and helps sleep later.

Plan demanding tasks

Schedule important work or chores for the time of day you usually feel most alert.

Be careful driving

If you feel very sleepy, avoid driving or operating machinery until you are rested.

CBT for insomnia is a structured programme, usually over several weeks, that tackles the habits and thoughts that keep poor sleep going. It is recommended as a first treatment for long-term insomnia, including in women after breast cancer.

Keeping a sleep diary

You record when you go to bed, how long it takes to fall asleep, how often you wake and how rested you feel. This shows patterns and measures progress.

Resetting the sleep window

Time in bed is matched more closely to the sleep you actually get, then gradually extended. It can feel tiring at first, but it strengthens the body's drive to sleep.

Changing unhelpful thoughts

Worries such as "I will never sleep again" or "tomorrow will be a disaster" raise tension. The therapy teaches calmer, more balanced ways of thinking about sleep.

Where to find it

Ask your team about psychologists who offer it, or reputable online programmes, which have also shown benefit.