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  • Dapsone (4,4′-diaminodiphenylsulfone) is a sulfonamide with unique pharmacologic action.

  • It is used as an antiinfective in particular against Hensen disease and selected fungal infections such as actinomycetoma and rhinosporidiosis. It is also used for the treatment of malaria and as a prophylaxis for toxoplasmosis.

  • It is also an antiinflammatory agents and is effective against dermatitis herpetiformis, erythema elevatum diutinum, linear immunoglobulin A dermatosis and chronic bullous disease of childhood, and bullous eruption of systemic lupus erythematosus.

  • It has antineutrophilic effect and used against collagen vascular and autoimmune diseases and recently topically for acne.

  • It is often used as corticosteroid-sparing agent.

  • Significant side effects to watch for include hemolysis and methemoglobinemia, which are frequently observed in patient with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Dapsone should only be given with great caution and in very special circumstances to patients with G6PD deficiency when the benefits outweigh the risks when constant hemoglobin and monitoring of reticulocyte counts is essential.

  • Other serious side effects include drug hypersensitivity syndrome (sulphone syndrome), Stevens-Johnson syndrome, and agranulocytosis.

  • Dapsone is classified as C Pregnancy Category (ie, risk not ruled out).


Dapsone is 4,4′-diaminodiphenylsulfone,1,2 an aniline derivative belonging to the group of synthetic sulfones. Although dapsone is classified as a sulfonamide, cross-reactions occur in only 7% to 22% of sulfa-allergic patients. They are usually mild.3,4

The molecule was synthesized in 1908, but research into dapsone as an antimicrobial agent started only in 1937.5,6 Later it was recognized to possess antiinflammatory effects, and it was investigated predominantly by in vitro studies aiming to get more information on the effect of dapsone on inflammatory effector cells, cytokines, and mediators, such as cellular toxic oxygen metabolism, myeloperoxidase-halogenid system, adhesion molecules, chemotaxis, membrane-associated phospholipids, prostaglandins, leukotrienes, interleukin-8, tumor necrosis factor-α (TNF-α), lymphocyte functions, and tumor growth. The latter capabilities primarily were used in treating chronic inflammatory disorders.

Hence, dapsone has dual functions, combining antimicrobial, antiprotozoal, and antiinflammatory effects resembling those of the nonsteroidal antiinflammatory drugs (NSAIDs).



Dapsone acts by interfering in the folate biosynthetic pathway. It inhibits the synthesis of dihydrofolic acid by competing with para-aminobenzoic acid for the active site of dihydropteroate synthetase.7,8 It has been used for the treatment of Hensen disease since 1945 (often in combination with other antibiotics, eg, rifampicin and clofazimine). It is also used to treat toxoplasmosis and is used for pneumocystis pneumonia (PCP) prophylaxis in immunocompromised patients in whom it is often prescribed in combination with pyrimethamine and leucovorin. It is also used as chemoprophylaxis for Plasmodium falciparum malaria.

In the early 2000s, a topical 5% dapsone gel was reported to be effective against acne without causing clinically significant declines in hemoglobin levels, even in ...

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