Hot flushes and sweats in women

Cancer or cancer treatment can lower the levels of sex hormones in the body. This can lead to hot flushes and sweats.

The main female sex hormones are oestrogen and progesterone.

Hot flushes are one of the most common symptoms women have when they go through the menopause. But hot flushes can also happen because of treatment for cancer.

Women having a natural menopause may find their hot flushes start before the menopause. They usually become less frequent and less severe during the 5 years after their last period. But for many, the hot flushes can go on longer.  

Hormone therapy to treat breast cancer 

Most women have hot flushes after hormone therapy for breast cancer treatment. This is because the treatment lowers or stops sex hormone production.

Chemotherapy and hot flushes 

If you are close to the age that you would naturally start the menopause when you have chemotherapy, you are more likely to go into the menopause. This means you are also more likely to have symptoms, such as hot flushes during your treatment.

How hot flushes may feel

Hot flushes can vary from one person to another. They can start as a sudden feeling of warmth in your neck or face. This often spreads to other parts of your body. You might have:

• reddening of the skin
• light or heavier sweating
• feelings of your heart beating in your chest (palpitations) 
• feelings of panic or irritability
• chills and shivering 

Hot flushes can last between 2 to 4 minutes but can be longer for some. How often you have them varies from person to person. You might have only 1 to 2 a day or several. Hot flushes are also common at night. And they can continue for many months or years. 

They can also make sleeping difficult, which can make you feel tired or anxious.

Causes of hot flushes

It's not exactly clear how hormonal changes cause hot flushes. The part of the brain called the hypothalamus controls the production of many hormones. It also controls our body temperature. There is more and more evidence that when oestrogen levels are low, nerve cells called KNDy neurons become overactive in the hypothalamus. The hypothalamus then becomes oversensitive. When there is a slight increase in the temperature around the body, the body overreacts by sweating and flushing in trying to cool down.

Researchers have been looking at using treatments that target KNDy neurons. One such drug is fezolinetant. It has been approved by the Medicines and Healthcare Products Regulatory Agency (MHRA) in the UK. So it is available on private prescription.

The National Institute for Health and Care Excellence (NICE) is reviewing this drug as a treatment for hot flushes and night sweats. If approved, it might be available through the NHS.

Tips to help with hot flushes

Some of the following tips might help to reduce the frequency or intensity of flushes.

• Keep your room cool – use a fan if necessary.

• Wear layers of light clothing so you can easily take clothes off if you overheat.

• Have layers of bedclothes to remove as you need to.

• Wear natural fibres such as silk or cotton instead of synthetic (artificial) fabrics.

• Spray your face with a cool water in a spray bottle, use a cold gel pack or use a handheld fan.

• Have a lukewarm shower or bath instead of a hot one.

• Put a towel on your bed so you can easily change it if you sweat a lot at night.

• Cooling pads or pillows can help to keep you cool.

• Try to stay calm under pressure as heightened emotions can cause a hot flush to start.

• Sip cold or iced drinks.

• Cut out or reduce alcohol and caffeine drinks such as tea and coffee.

• Reduce or stop smoking (nicotine).

• Cut out or reduce the spicy foods you eat.

Hot flushes usually start to improve over time.

Treatment for hot flushes

If you are finding it difficult to manage your hot flushes, do talk to your doctor or specialist nurse. There are medicines that may help, but not all treatments are suitable for everyone.

Keeping a diary

Hot flushes are often triggered by certain foods or drinks. Some people find that keeping a diary of their hot flushes can help them manage this problem. You can show the diary to your doctor or specialist nurse. 

Drug treatment for hot flushes

Antidepressants

Research has shown that certain antidepressant medicines can be helpful in treating hot flushes. 

The most effective ones are:

• venlafaxine
• paroxetine
• citalopram

They can reduce the number and severity of hot flushes. 

But doctors don’t recommend fluoxetine or paroxetine if you are taking tamoxifen. They may interfere with how well tamoxifen works.

The dose you have for hot flushes is usually lower than the dose used to treat depression. Remember that all drugs have some side effects. Antidepressants can cause:

• a dry mouth
• headaches
• feeling sick
• loss of appetite

Gabapentin

Gabapentin is used to treat seizures and nerve pain. Studies found that it can also help to reduce hot flushes.

Side effects of gabapentin include dizziness and drowsiness. Some women also develop a rash and fluid retention.

Clonidine

Clonidine is a drug used for a variety of conditions, including high blood pressure.

It can reduce the number of hot flushes. But it doesn’t reduce their severity or how long they last. Doctors usually recommend trying other treatments before starting clonidine. 

Side effects include:

• dizziness
• a dry mouth
• constipation
• drowsiness
• difficulty sleeping

Oxybutinin

Oxybutinin is a drug used to treat an overactive bladder. Several studies have shown that it can reduce the number of hot flashes. Side effects may include:

• a dry mouth and eyes
• dizziness
• your bladder not emptying completely (urinary retention)
• drowsiness
• constipation
• vision changes
• feeling sick

Hormone replacement therapy (HRT)

One way to help control hormonal symptoms is to take hormones to replace the ones your body is no longer producing. Hormone replacement therapy (HRT) is an effective treatment for many women. But some treatments for breast cancer aim to either stop the body producing sex hormones, or block their action. If you are having these treatments, you can’t unfortunately take HRT.

Doctors don’t routinely recommend that you take HRT if you have a hormone dependent cancer, such as breast cancer. Even if you have finished treatment there is concern that HRT may increase the risk of cancer coming back. Talk to your specialist if you are finding it difficult to cope with your symptoms. They can explain the risks and benefits of HRT and if this is an option for you.

Other therapies

Cognitive behavioural therapy (CBT)

CBT is a talking therapy. It can help you manage your problems by changing the way you think and behave. CBT for hot flushes can help you with how you think about and control them. It focuses on:

• calming your body and mind
• keeping a positive outlook towards menopause
• improving your sleep

You can ask your doctor or specialist nurse whether CBT is available in your area.

Acupuncture

Acupuncture has been researched as a treatment for hot flashes in women. Researchers did a systematic review and meta analysis in 2021. They found that:

• compared to hormone replacement therapy (HRT), acupuncture was not better in reducing the number of hot flushes
• acupuncture increased the quality of life of women

The researchers said that acupuncture could be used to treat hot flushes but that we need better quality research.

Supplements

There are many supplements available for the relief of hot flushes. Generally, the evidence for their use is mixed or limited. But some women have found them useful.

It is worth bearing in mind that products can vary in terms of the dose and what they contain. And some may interact with other medicines you are taking, making these less effective or causing side effects. So always check with your doctor or pharmacist first.

Soy and red clover are phytoestrogens. They work in the body in a similar way to the hormone oestrogen. So it is not certain how safe these are for those who have breast cancer, or have had it in the past. Speak to your doctor if you are thinking of taking these.

Some studies show that Black Cohosh helps with hot flushes, but it can cause severe side effects such as:

• constipation
• changes to your heart rhythm
• weight gain
• tummy cramps 

Black Cohosh also interferes with the way tamoxifen works. So it should be avoided if you are taking tamoxifen for breast cancer.

There is some evidence that St John’s Wart helps with hot flushes. It is not clear what dose is best and for how long it would be effective. There is also a risk of serious interactions with other medicines. It may change how well a medicine is processed by the body, including the drug tamoxifen.

St John’s Wart is not recommended for people with a history of, or at higher risk of, breast cancer.