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Patient Information Leaflet

Dapsone

What are the aims of this leaflet?

This leaflet has been written to help you understand more about dapsone.  It tells you what it is, what causes it, how it can be used to treat skin conditions, and where you can find out more about it.

What is dapsone and how does it work?

Dapsone is an antibacterial medicine belonging to the sulphonamide class, which is available on prescription from your doctor. It was originally used for treatment of leprosy. More recently it has been used as a treatment for several other skin conditions.

Which skin conditions are treated with dapsone?

Dapsone is used to control inflammation in a variety of conditions such as dermatitis herpetiformis, pyoderma gangrenosum, vasculitis, Henoch Schönlein purpura, Sweet's disease and other diseases.

When should you not use dapsone?

If you know that you are allergic to dapsone, or have had serious reactions to the sulphonamide group of tablets, you should not take dapsone. Let your doctor know if you have significant heart or lung disease because the dose of dapsone may then have to be lower than usual. 

What are the potential side effects of dapsone?

Some people experience mild headaches or sickness. Changes in the red blood pigment (haemoglobin) can lead to a bluish discolouration of lips and fingertips that does not cause other symptoms.

More important problems require medical monitoring but fortunately are rare. They include anaemia, shortness of breath and tiredness. This is much more prominent if you have a genetic condition called glucose-6-phosphate dehydrogenase (G6PD) deficiency. People of Mediterranean, African and Asian ancestry are especially at risk and can be tested for this deficiency before dapsone is started.  

Rarely, a serious fall in the blood count can cause fever, mouth ulcers, a sore throat or bruising. Allergy to dapsone can cause fever, a rash and swelling of glands in the neck.   Dapsone should be stopped if an allergy is suspected.

Are there any other side effects if dapsone is taken for a long time?

Rarely, prolonged use can lead to impaired function of nerves in the limbs, causing weakness of muscles in the hands and feet.  

What dose should I take?

Your doctor will advise you here. Dapsone is available in tablet form at strengths of 50mg and 100mg.  Normal doses would be in the range of 50 to 200 mg daily.

How will I be monitored for the side effects of dapsone treatment?

You will need blood tests to make sure that your blood and liver are working normally before starting dapsone. These tests will take place frequently after starting it, and thereafter every three months while you remain on the dapsone. An urgent blood count needs to be taken in between if you develop any of the symptoms or side effects mentioned above.  

Does dapsone affect fertility or pregnancy?

Dapsone can reduce the number of sperm and their mobility. It does not affect the development of the growing baby. Dapsone should be avoided in pregnancy if possible, but has been used safely. The greatest risk to a baby in the womb is in the last 3 months, and can be reduced if folic acid, a vitamin, is taken. Dapsone enters breast milk and can be harmful to babies with G6PD deficiency.

May I drink alcohol while taking dapsone?

Yes 

Can I take other medicines at the same time as dapsone?

The more important drug interactions are with probenecid which increases dapsone levels and with the antibiotics trimethoprim and rifamycins which lower blood levels.

It is important that you always tell your doctor and pharmacist that you are taking Dapsone

Where can I find out more about dapsone?

This information sheet does not list all the side effects this type of drug can cause. For fuller details, please look at the drug information leaflet that comes with your medicine. Your doctor will assess your medical circumstances and draw your attention to side effects that may be relevant in your particular case. 

The British Skin Foundation fund vital research into all skin diseases.  To find out how you can help, please visit the British Skin Foundation website here.

(While every effort has been made to ensure that the information given in this leaflet is accurate, not every treatment will be suitable or effective for every person. Your own doctor will be able to advise in greater detail).

BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED SEPTEMBER 2007