Dapsone was synthesized in 1908 by Fromm and Wittmann. The drug was approved by FDA for the treatment of such conditions as acne vulgaris, leprosy and dermatitis herpetiformis, also the drug is used off-label for many skin diseases. Although the exact mechanism of dapsone action is unknown, it is speculated that it acts as both anti-inflammatory and antimicrobial agent. It was demonstrated that dapsone suppresses ROS generation, inhibits neutrophil myeloperoxidase and eosinophil peroxidase and also inhibits bacterial dihydropteroate synthase.

Clofazimine (Lamprene®) is a fat-soluble riminophenazine dye used for the treatment of leprosy. It has been used investigationally in combination with other antimycobacterial drugs to treat Mycobacterium avium infections in AIDS patients. Clofazimine (Lamprene®) exerts a slow bactericidal effect on Mycobacterium leprae (Hansen’s bacillus). It inhibits mycobacterial growth and binds preferentially to mycobacterial DNA. It also exerts anti-inflammatory properties in controlling erythema nodosum leprosum reactions. However, its precise mechanisms of action are unknown.