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 which is available only on prescription. While classified as antibiotic, dapsone acts as an anti-inflammatory drug and has been used  as a treatment for several skin conditions, such as dermatitis herpetiformis, pyoderma gangrenosum, Sweet syndrome and vasculitis for many years. It can, under the supervision of healthcare professionals, 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 healthcare professional about these conditions.

What are the potential side effects of dapsone? 

Dapsone is usually well tolerated, but the treatment should start with some caution, considering how your body responds to it and if you experience any side effects. Some people experience mild headaches or sickness. Changes in haemoglobin (the pigment that gives blood its colour) can make the lips and fingertips appearing slightly blue.

Rarely, dapsone may cause bone marrow suppression (a decrease in the ability of the bone marrow to produce blood cells) which can lead to fever, mouth ulcers, a sore throat, bruising or prolonged bleeding.

Dapsone may cause anaemia (low red cell count or low haemoglobin) shortness of breath and tiredness, especially in those with a genetic condition called glucose-6-phosphate dehydrogenase (G6PD) deficiency. This results in low levels of an enzyme called G6PD. This condition is more common in those with Mediterranean, African and Asian ancestry. The level of G6PD enzyme can be tested for this deficiency before dapsone is prescribed. Your prescribing healthcare professional 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 immediately if you have an allergic reaction and seek advice from your GP or dermatologist as soon as possible.

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

In rare cases, using dapsone for a long time at a high dose can affect the nerves in the limbs. This can result in weakness of the muscles in the hands and feet. However, it is important to note that this is uncommon and occurs only after months or even years of continuous use. If you experience any unusual weakness or muscle problems while taking dapsone, it is best to consult your healthcare provider.

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 before starting dapsone. This is to make sure your blood counts, liver, and kidney functions are normal. Initially you will start dapsone at a low dose which gradually may be increased if this is necessary. Your healthcare professional will discuss this with you. After you start taking dapsone, you will need to have blood tests frequently at first. Once your dose is stable, the tests can be done every three months. If you experience any of the symptoms mentioned earlier, you must have an urgent blood count test immediately.

Does dapsone affect fertility or pregnancy? 

Dapsone may lower the number and movement of sperm. It does not affect the developing baby. Studies on dapsone use during pregnancy have not shown an increased risk of birth defects. However, dapsone should only be taken during pregnancy when the benefits outweigh the risks. If dapsone is to be taken during pregnancy, it is recommended to also take 5 mg of folic acid 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.

However there may be other medication that you need to avoid which are not on this list, so it is important that you always tell your healthcare professional 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.

http://dermnetnz.org/treatments/dapsone.html

http://www.emedicinehealth.com/drug-dapsone/article_em.htm

http://www.drugs.com/uk/pdf/leaflet/137510.pdf

https://www.medicines.org.uk/emc/files/pil.5769.pdf

Jargon Buster: https://www.skinhealthinfo.org.uk/support-resources/jargon-buster/

Please note that the BAD provides web links to additional resources to help people access a range of information about their treatment or skin condition. The views expressed in these external resources may not be shared by the BAD or its members. The BAD has no control of and does not endorse the content of external links. 

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, SEPTEMBER 2023
NEXT REVIEW DATE | SEPTEMBER 2026