How does it work?

Dapsone is a medication which has an antileprotic and antimalarial action.It works inside the infecting cell to stop the manufacture of a chemical called folinic acid. Folinic acid is necessary for the production of genetic material (DNA). Without the production of DNA the infecting organism is not able to reproduce, and the spread of the infection is stopped.The main use of dapsone is in the treatment of leprosy in combination with other drugs. Through an unknown mechanism dapsone is also effective in treating the rare skin condition known as dermatits herpetiformis.Dapsone is also sometimes used in combination with the drug pyrimethamine and chloroquine for the prevention of malaria in certain areas where there is a high risk of chloroquine resistant Plasmodium falciparum malaria.

What is it used for?

• An itchy blistering rash due to gluten allergy (dermatitis herpetiformis)
• Leprosy
• Prevention of Plasmodium falciparum malaria

Warning!

• This medicine may rarely cause a decrease in the normal amounts of blood cells in the blood. For this reason you should consult your doctor immediately if you experience any of the following symptoms: unexplained bruising or bleeding, purple spots, sore throat, mouth ulcers, high temperature (fever), feeling tired or general illness. Your doctor may want to take a blood test to check your blood cells.

Use with caution in

• Anaemia
• Heart disease
• Lack of the enzyme G6PD in the blood (G6PD deficiency)
• Lung disease

Not to be used in

• Life long inherited blood diseases which can cause a variety of symptoms, including mental health problems (porphyrias)

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

• This medicine should be avoided in the third trimester of pregnancy, as it may affect the growth and development of the foetus or have harmful effects on foetal tissues. Seek medical advice from your doctor before using this medicine during any stage of pregnancy.
• This medicine passes into breast milk. Seek medical advice from your doctor before using this medicine during breastfeeding.

Label warnings

• Do not stop taking this medication except on your doctor's advice.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

• Headache
• Difficulty in sleeping (insomnia)
• Inflammation of the liver (hepatitis)
• Loss of contact with reality (psychosis)
• Disorder of the peripheral nerves causing weakness and numbness (peripheral neuropathy)
• Nausea and vomiting
• Loss of appetite
• Destruction of red blood cells (haemolysis)
• Rash with a fever and a decrease in numbers of certain immune cells (Dapsone syndrome).
• Inability of red blood cells to transport oxygen due to disorders of haemoglobin (methaemoglobinaemia)
• Sudden severe deficiency in the number of white blood cells in the blood (agranulocytosis)
• Allergic dermatitis

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

The blood concentration of dapsone is reduced by rifampicn and rifabutin.The removal of dapsone from the body by the kidneys is reduced by probenecid and so increases the risk of side effects.