Dapsone

Products

Dapsone is approved in Germany in tablet form (Dapsone-Fatol). In the USA, it is additionally on the market as a gel for the treatment of acne (Aczone). No preparations are currently registered in many countries.

Structure and properties

Dapsone or 4,4′-diaminodiphenylsulfone (C12H12N2O2S, Mr = 248.3 g/mol) is a sulfone and aniline derivative with structural similarities to the sulfonamides. It exists as a white to slightly yellowish white crystalline powder that is very sparingly soluble in water due to its lipophilicity.

Effects

Dapsone (ATC D10AX05, ATC J04BA02) is antibacterial against , and streptococci, antiparasitic against protozoa and plasmodia, and anti-inflammatory. The antimicrobial effects are due to inhibition of folic acid synthesis.

Indications

Dapsone is used in the form of tablets for the treatment of blistering and inflammatory skin diseases, chronic articular rheumatism, leprosy, malaria, pneumocystis pneumonia, and against rheumatism. The gel is applied locally against acne vulgaris. Numerous other possible applications are described in the literature.

Contraindications

Dapsone is contraindicated in hypersensitivity, hypersensitivity to sulfonamides, sulfones, and severe liver disease. For complete precautions, see the drug label.

Interactions

Dapsone is acetylated in the liver to its major metabolite, monoacetyl dapsone. This process is subject to pharmacogenetic differences. Drug-drug interactions have been observed with omeprazole, probenecid, trimethoprim, rifabutin, rifampicin, ursodeoxycholic acid, pyrimethamine, methemoglobin formers, fluconazole, and zidovudine.

Adverse effects

Possible adverse effects include, in descending frequency, headache, gastric discomfort, nausea, methemoglobin formation, hypersensitivity (“dapsone syndrome,” including fever, malaise, skin reactions, jaundice, anemia, renal vasculitis, and hepatitis), peripheral motor neuropathy, hypalbuminemia, agranulocytosis, pancreatitis, photosensitivity, and pneumonitis.