[What do we know today about diaminodiphenylsulfone?]

Diaminodiphenylsulfone or dapsone is a chemical analogue of sulfapyridine, synthesized in 1908. Dapsone is a bacteriostatic agent that proved to be efficient in treating leprosy and malaria, but today it is used in treating dermatologic noninfectious inflammatory diseases.

Dapsone is orally used in a dose of 50-400 mg per day in treatment of dermatologic diseases, and also in a dose of 50-100 mg per day in leprosy treatment. Dapsone is mainly eliminated from the body by urine and smaller part by faeces. Pharmacological interaction was reported when it is used with rifampicin and probenecid.

The bacteriostatic effect of dapsone is well known. It involves inhibition of folic acid synthesis in susceptible organisms. The anti-inflammatory effect of dapsone, which proves to be efficient in treating noninfectious inflammatory diseases, has not been explained completely yet. There are some pieces of evidence that anti-inflammatory action is not connected with its antibacteriological action.

Based on previous studies about therapy efficiency of dapsone in treating some diseases, there are two groups of diseases: the group responding well to dapsone (leprosy, malaria, DH, linear IgA-dermatosis, erythema elevatum diutinum, bullous systemic lupus erythematosus) and a group responding with average good response to dapsone (pyoderma gangrenosum, bullous and cicatricial pemphigoid, acne conglobata, discoid cutaneous lupus erythematosus, subcorneal pustulosis dermatosis, granuloma faciale, rheumatoid arthritis, polychondritis, leucocytoclastic vasculitis).

Adverse effects depend on the dose and they rarely occur at doses less than 100 mg per day. They are mainly shown on skin, nervous system, digestive system, hepatobiliary system, and kidney and hematologic system. The most important adverse effects are hemolytic anaemia and methemoglobinemia. Hemolysis usually occurs at doses of 200 mg and more per day. In patients with glucose-6-phosphate dehydrogenase deficiency, hemolysis may be provoked by a dose less than 50 mg per day. For prevention, before using dapsone in therapy, clinical examination with history, blood parameters, liver and renal parameters and determination of glucose-6-phosphate dehydrogenase level are recommended.

The use of dapsone is absolutely indicated in DH treatment and erythema elevatum diutinum. Because of anti-inflammatory effects, dapsone can also be used in treating other inflammatory noninfectious dermatoses when one should take care about "therapy efficiency/adverse effect" balance using the correct dose, monitoring relevant clinical and laboratory parameters and educating patients.