Innovative Use of Dapsone

After synthesis of dapsone (4,4′ diaminodiphenylsulfone) in 1908, the compound was known exclusively in chemistry. Following the epoch-making discovery of the antimicrobial potential for sulfonamides emerged, the sulfone class was included in the medical armamentarium. The therapeutic role of sulfones related to both pathogen-caused diseases and chronic inflammatory dermatoses has led to extensive use in dermatology. At present dapsone is the only sulfone congener available for clinical practice. The sulfone is used in rifampin-based multiple-drug regiments to treat multibacillary and paucibacillary leprosy and to treat Pneumocystis jiroveci pneumonia and prevent toxoplasmosis in individuals with AIDS. In dermatology, dapsone is the preferred drug for treating dermatitis herpetiformis (Duhring’s disease) and is useful in the management of a broad range of chronic inflammatory entities, especially autoimmune bullous disorders. With proper administration and monitoring, the sulfone should be considered a useful and safe agent.

In the past, sulfones were used preferentially as antimicrobial/chemotherapeutic agents to treat infections caused by streptococcus, mycobacteriaceae, and other bacteria. Currently, dapsone (4,4′ diaminodiphenylsulfone) is the only remaining sulfone congener used in human therapeutics. Because of its dual mechanism of action—antimicrobial and anti-inflammatory/immunomodulatory effects—dapsone alone or in conjunction with other drugs is used worldwide for preventing and treating pathogen-caused diseases (eg, leprosy, Pneumocystis jiroveci pneumonia in individuals with HIV infection) or chronic inflammatory diseases, especially in the field of dermatology (eg, autoimmune bullous eruptions).

Synthesis of dapsone was reported in 1908 by Emil Fromm ( Fig. 1 ), professor of organic chemistry in Freiburg/Germany, and Jakob Wittmann during their experiments in dye chemistry. When first synthesized, dapsone was not envisioned as a medical agent. In 1937, soon after the discovery of sulphonamides as antibiotics, two research groups (one in England and one in France) were the first to investigate dapsone. Both groups concurrently published the observed anti-inflammatory potency of dapsone in experimentally induced infections in mice. In the narrowest sense, that marked the beginning of the sulfone story.