Cancer or its treatments can sometimes make you feel sick or be sick. Chemotherapy, radiotherapy, hormonal therapy and targeted therapy can all cause sickness. Physical changes can cause these side effects too. For example, this might be because of damage to the liver or pressure on the brain. If you’re feeling anxious about cancer and your treatment, this can also make you feel or be sick.
There are many different types of drugs that help treat sickness. These are called anti-emetics. They can be given as a tablet, an injection, a suppository or a skin patch. If you’re having a cancer treatment which is known to cause sickness, you should start taking anti-emetics before your treatment starts.
Being sick can be a problem when you have diabetes. Because you may not be able to eat or drink, you could become dehydrated. This can be more serious for people with diabetes.
You will need to check your blood sugar more often, possibly every two to four hours. You may need to check for ketones if your blood sugar is very high and you use insulin to control your diabetes. Ketones are chemicals that can sometimes build up in the body when there is a severe lack of insulin. Ketones are toxic to the body and large amounts can be very serious. If you have ketones, you should contact your diabetes team for advice straight away.
If you use insulin, you will usually have this before eating. But if you are sick, you may not absorb enough food and your blood sugar may drop too low. If you are sick after eating, check your blood sugar and try to eat something to stop the blood sugar getting too low. It is a good idea to have a fast-acting carbohydrate to hand, such as glucose tablets, sweets or fruit juice.
If you are being sick, you may need to change the dose of your insulin or change the type of insulin you use. You should not stop taking it.
If you use tablets to manage your diabetes, you may need to stop taking them while you are being sick. Your diabetes team can give you more advice.
Tips to help you cope with sickness
- It is important to plan ahead. Before you start any cancer treatment, talk to your cancer doctor or specialist nurse. Explain that you have diabetes and that you need to prevent sickness as much as possible.
- Ask your diabetes team for advice about managing sickness before it happens. They can tell you how to manage your diabetes when you are ill, known as the 'sick-day rules'. It is helpful for family or friends to know how to manage things too.
- Take your anti-sickness medicines as they are prescribed, even if you are not feeling sick. It is easier to prevent sickness before it starts than control it.
- Tell the doctor if the anti-sickness medicines are not working. They can give you different medicines that may work better.
- Try to stick to your normal diet and eat the same amount of carbohydrates that you normally do. But if you are struggling to do this, it is okay to eat foods you wouldn’t normally eat.
- Try eating dry foods and avoid greasy, fatty or fried foods.
- Ginger can help reduce sickness. Try drinking ginger tea or eating ginger biscuits.
- Eat cold foods, such as yogurt and ice cream, or foods at room temperature, such as tinned fruit, dry toast and plain biscuits.
- If the smell of cooking makes you feel sick, eat cold meals or food from the freezer that only needs heating up.
- If feeling sick is putting you off food or you can’t keep food down, replace meals with snacks or drinks that contain carbohydrates, such as glucose tablets, fruit juice or non-diet fizzy drinks.
- Try to keep drinking even if you can’t manage to eat. Aim to drink a cup of fluid every hour.
If you can’t keep any fluids down, contact the hospital as soon as possible. It is important to prevent dehydration.
You should talk to your diabetes team if you are worried about coping with sickness. They will be able to give you more advice.