In Canada—

Another commonly used name is DDS.

• Antibacterial, antileprosy agent
• Antifungal, systemic
• Antiprotozoal
• Dermatitis herpetiformis suppressant

Dapsone (DAP-sone) , a sulfone, belongs to the family of medicines called anti-infectives.

Dapsone is used to treat leprosy (Hansen's disease) and to help control dermatitis herpetiformis, a skin problem. When it is used to treat leprosy, dapsone may be given with one or more other medicines. Dapsone may also be used for other conditions as determined by your doctor.

Dapsone is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For dapsone, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to dapsone or sulfonamides. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies have not been done in humans or animals. However, reports on the use of dapsone in humans have not shown that this medicine causes birth defects or other problems.

Breast-feeding—Dapsone passes into the breast milk. Dapsone may cause blood problems in nursing babies with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Breast-feeding may need to be stopped because of the risks to the baby.

Children—Although there is no specific information comparing use of dapsone in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of dapsone in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking dapsone, it is especially important that your health care professional knows if you are taking any of the following:

• Acetohydroxamic acid (e.g., Lithostat) or
• Antidiabetics, oral (diabetes medicine you take by mouth) or
• Furazolidone (e.g., Furoxone) or
• Methyldopa (e.g., Aldomet) or
• Nitrofurantoin (e.g., Furadantin) or
• Primaquine or
• Procainamide (e.g., Pronestyl) or
• Quinidine (e.g., Quinidex) or
• Quinine (e.g., Quinamm) or
• Sulfonamides (sulfa medicine) or
• Vitamin K (e.g., AquaMEPHYTON, Synkayvite)—Use of dapsone with these medicines may increase the chance of side effects affecting the blood

• Dideoxyinosine (e.g., ddI, Videx)—Use of dideoxyinosine with dapsone may decrease the effectiveness of dapsone

• Anemia (severe) or
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency or
• Methemoglobin reductase deficiency—There is an increased risk of severe blood disorders and a decrease in red blood cell survival

• Liver disease—Dapsone may on rare occasion cause liver damage

For patients taking dapsone for leprosy:

• To help clear up your leprosy completely or to keep it from coming back, it is very important that you keep taking this medicine for the full time of treatment, even if you begin to feel better after a few weeks or months. You may have to take it every day for as long as 3 years or more, or for life. If you stop taking this medicine too soon, your symptoms may return.
• This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. Also, it is best to take each dose at the same time every day. If you need help in planning the best time to take your medicine, check with your health care professional.

For patients taking dapsone for dermatitis herpetiformis:

• Your doctor may want you to follow a gluten-free diet. If you have any questions about this, check with your doctor.

Dosing—

The dose of dapsone will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of dapsone. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking dapsone.

• For oral dosage form (tablets):
  • For Hansen's disease (leprosy):
    • Adults and teenagers—50 to 100 milligrams (mg) once a day; or 1.4 mg per kilogram (kg) (0.6 mg per pound) of body weight once a day. Dapsone should be taken with other medicines to treat Hansen's disease.
    • Children—Dose is based on body weight. The usual dose is 1.4 mg per kg (0.6 mg per pound) of body weight once a day. Dapsone should be taken with other medicines to treat Hansen's disease.
  • For dermatitis herpetiformis:
    • Adults and teenagers—50 mg once a day to start. Your doctor will increase your dose, up to 300 mg once a day, until your symptoms are controlled. Then your dose will be decreased to the lowest dose that will still control your symptoms.
    • Children—Dose is based on body weight. The usual dose is 2 mg per kg (0.9 mg per pound) of body weight once a day to start. Your doctor will increase your dose until your symptoms are controlled. Then your dose will be decreased to the lowest dose that will still control your symptoms.

Missed dose—

You may skip a missed dose if it does not make your symptoms come back or get worse. If your symptoms do come back or get worse, take the missed dose as soon as possible. Then go back to your regular dosing schedule.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is very important that your doctor check your progress at regular visits.

If your symptoms do not improve within 2 to 3 months (for leprosy), or within a few days (for dermatitis herpetiformis), or if they become worse, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• More common
  • Back, leg, or stomach pains;  bluish fingernails, lips, or skin;  difficult breathing;  fever;  loss of appetite;  pale skin;  skin rash;  unusual tiredness or weakness 
  
  

• Rare
  • Itching, dryness, redness, scaling, or peeling of the skin, or loss of hair;  mood or other mental changes;  numbness, tingling, pain, burning, or weakness in hands or feet ;  sore throat;  unusual bleeding or bruising;  yellow eyes or skin 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• Rare
  • Headache;  loss of appetite;  nausea or vomiting;  nervousness;  trouble in sleeping 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not specifically included in product labeling, dapsone is used in certain patients with the following medical conditions:

• Actinomycotic mycetoma
• Granuloma annulare
• Malaria (prevention of)
• Pemphigoid
• Pneumocystis carinii pneumonia
• Pyoderma gangrenosum
• Relapsing polychondritis
• Subcorneal pustular dermatosis
• Systemic lupus erythematosus

For patients taking this medicine for Pneumocystis carinii pneumonia (PCP):

• To help clear up PCP completely or to keep it from coming back, it is very important that you keep taking this medicine for the full time of treatment.
• If you miss a dose of this medicine, take it as soon as possible. This will help keep a constant amount of medicine in the blood. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
• If your symptoms do not improve within 1 week, or if they become worse, check with your doctor.

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.