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, how it can be used to treat skin conditions, and where you can find out more about it.
What is dapsone and what conditions are treated with it?
Dapsone is a sulphonamide antibiotic. It is available only on prescription. It acts as an anti-inflammatory drug and has been used successfully as a treatment for several skin conditions such as dermatitis herpetiformis, pyoderma gangrenosum, Sweet’s syndrome and vasculitis for many years. It can, under supervision of your dermatologists, also be used for other inflammatory skin conditions that are not mentioned here if none of the standard treatments are effective.
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 medicines, you must not take dapsone. The dose of dapsone may need to be lower than usual if you have a heart or lung disease, have a condition called G6PD deficiency (see below) or if you are anaemic. It is important to tell your doctor about these conditions.
What are the potential side effects of dapsone?
Dapsone is usually well tolerated, but should be started cautiously. Some people experience mild headaches or sickness. Changes in the red blood pigment (haemoglobin) can lead to the lips and fingertips having a bluish appearance. Rarely, it may cause bone marrow suppression (a decrease in the ability of the bone marrow to produce cells) which can cause fever, mouth ulcers, a sore throat, bruising or prolonged bleeding.
Dapsone may cause anaemia, shortness of breath and tiredness, especially in those with a genetic condition called glucose-6-phosphate dehydrogenase (G6PD) deficiency which is more common in those with Mediterranean, African and Asian ancestry. The level of G6PD can be tested for this deficiency before dapsone is prescribed. Your doctor should check whether you have G6PD deficiency before prescribing dapsone.
Allergy to dapsone can cause fever, a rash and swelling of glands in the neck, armpits and groins (lymphadenopathy). Please stop dapsone if you have an allergic reaction and seek advice from your GP or dermatologist.
Are there any other side effects if dapsone is taken for a long time?
Rarely, prolonged use of dapsone over months or years at a high dose 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 on the correct dose to take. Dapsone is available in tablet form at strengths of 50 mg and 100 mg. The usual dose would be in the range of 50 to 200 mg daily.
How will I be monitored for the side effects of dapsone treatment?
It is important to have a blood test to make sure your blood counts, liver and kidney functions are normal before starting dapsone. Blood tests will take place frequently after first starting dapsone and can be reduced to every three months when the dose is stabilised. An urgent blood count needs to be taken immediately if you develop any symptoms as outlined 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. If dapsone has to be taken in pregnancy then mother should take folic acid 5 mg daily.
Does dapsone affect breast feeding?
Yes, dapsone can be found in breast milk but the risk to babies is very small unless they have G6PD deficiency.
May I drink alcohol while taking dapsone?
Yes, always in moderation.
What other medicines I should avoid when taking dapsone?
You should avoid probenecid (a treatment for gout), the antibiotics trimethoprim and rifampicin, saquinavir (a treatment for HIV infection) and typhoid vaccine.
It is important that you always tell your doctor and pharmacist 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.
For details of source materials used please contact the Clinical Standards Unit (firstname.lastname@example.org).
This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.
This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel
BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED SEPTEMBER 2007
UPDATED DECEMBER 2010, JANUARY 2014, DECEMBER 2016, MAY 2020
REVIEW DATE MAY 2023