A dry mouth can be a distressing side effect of cancer treatments and if prolonged can lead to pain and soreness. A dry mouth can lead to secondary infection and bleeding. Lack of saliva then causes difficulty swallowing as it is hard to chew food and form a bolus. A dry mouth also causes problems with speech as the tongue tends to stick to the side or roof of the mouth. This page describes the common causes of a dry mouth during or after cancer treatments and suggests some practical tips which may help.

Common causes of a dry mouth:

• Mouth breathing e.g. a blocked nose
• Painkillers - opiates, codeine
• Antisickness - hyoscine
• Antidepressants or amtitrypiline
• Damage to the salivary glands - particularly after radiotherapy to the head and neck area
• After prolonged chemotherapy regimens, saliva production can temporarily reduce
• Dehydration from any cause
• High calcium in blood stream (hypercalcaemia)
• Previous medical conditions e.g. autoimmune diseases affecting the gland

Tips for a dry mouth

Good mouth care when you have a dry mouth can help to keep the mouth clean, moist and comfortable. It is especially important to take good care of your mouth while you are receiving treatment: Careful attention to mouth care will help reduce the risks of infection and the following instructions are designed to help you keep your mouth clean and comfortable. If a dry mouth becomes inflamed this is called oral mucositis often can be painful, and this in turn can make it difficult to eat and drink.  

Clean teeth thoroughly but gently after each meal and before going to bed. If the gums are delicate it is better to use a soft toothbrush (baby/infant).

Brand name antibacterial mouthwashes such as Corsodyl may be used but are quite strong and may damage the fragile lining of your mouth whilst on treatment. Check with nursing staff for further advice.

Saline mouthwashes are recommended if tolerable; 5 mls salt: 500 mls tepid water; (1 tsp. salt: one pint tepid water). If you are suffering from a mark dry mouth, this supervising doctor needs to be told, otherwise, the following suggestions may help:

• Have frequent drinks, even just a few sips at a time to keep your mouth moist.  Fizzy drinks may be most refreshing
• Avoid alcohol or smoking
• Try sucking ice cubes/ice lollies (these can be flavoured with cordials, fruit juice or juice based supplements
• Try making home-made lollies or in the freezer using fruit juice and/or supplements
• Moisten food with lots of  gravy or sauces, butter, custard, cream
• Some people report that chocolate and pastry stick to the roof of the mouth-avoid them if they do
• Try sucking sugar free boiled sweets, fruit drops/pastilles, chewing gum or try eating pineapple chunks or grapefruit segments to increase saliva flow
• Artificial saliva preparations are available and can be prescribed by your doctor if   felt appropriate
• Use a mouthwash and brush your teeth regularly
• Keep lips moist with lip balm
• Avoid wearing denture

It may be necessary to change the diet to foods which are soft and moist. Also if there are signs of secondary infection further treatment may be needed.

Signs of infection in the mouth:

• red areas
• pain and swelling
• blisters
• white spots
• coated tongue
• bleeding

Treating a painful mouth

• Treat infection
• Fundal (candida) with antifungals such as fluconazole
• Saline mouthwashes (see above) - Use two tablets in tepid water, swill around the mouth for two to three minutes but do not swallow. Useful before meals but it is best not to eat or drink anything for 10 minutes after using the mouthwash, to gain maximum effect from it. May be used frequently during the day, provided they are not swallowed.
• Soluble Paracetamol mouthwash/gargle.
• Sore lips may be helped with Paracetamol mouthwash.
• Vaseline is also useful to prevent dryness and cracking. 
• Oral barrier gels (e.g.gelclair)
• Painkilling brand name mouthwashes, e.g. Difflam may be useful but please check with nursing staff before using as some consultants prefer not to prescribe them
• In some cases you will be advised to suck ice/ice-lollies immediately prior to and during chemotherapy. This is to reduce damage from certain drugs.

Further information