Before Using This Medicine

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

Other medical problems—The presence of other medical problems may affect the use of dapsone. Make sure you tell your doctor if you have any other medical problems, especially:

• 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