Uses

Dapsone is a sulfone antimicrobial used for the treatment of all forms of leprosy (except confirmed dapsone-resistant cases) and dermatitis herpetiformis. Topical dapsone gel is indicated for acne vulgaris.

Do not use if

Contraindicated in patients with known hypersensitivity to dapsone or its derivatives.

Side effects

Dose-related hemolysis is the most common adverse effect, occurring in patients with or without G6PD deficiency. Other important effects include methemoglobinemia, agranulocytosis, aplastic anemia, and peripheral neuropathy. A dapsone hypersensitivity syndrome (fever, rash, lymphadenopathy) can occur within the first 6 weeks.

Warnings

Monitor complete blood counts regularly due to risk of agranulocytosis and aplastic anemia. Patients should be advised to report sore throat, fever, pallor, purpura, or jaundice immediately. Test for G6PD deficiency before initiation when possible. Use with caution in hepatic impairment.

How it works

Dapsone is bactericidal and bacteriostatic against Mycobacterium leprae by inhibiting dihydropteroate synthase, thereby blocking folate synthesis (similar mechanism to sulfonamides). In dermatitis herpetiformis, the mechanism of action is not fully established but may involve inhibition of neutrophil function. Oral dapsone is rapidly and almost completely absorbed.

Storage

Store at 20°C–25°C (68°F–77°F); excursions permitted to 15°C–30°C (59°F–86°F). Protect from light.