Conditions Dapsone is Used For
Dapsone is FDA-approved for two primary conditions: dermatitis herpetiformis (as primary treatment) and leprosy (as an antibacterial for susceptible cases), but it has extensive off-label use in dermatologic conditions, HIV-related prophylaxis, and autoimmune disorders. 1
FDA-Approved Indications
- Dermatitis herpetiformis: Primary treatment indication 1
- Leprosy: Antibacterial treatment for susceptible cases, typically used in multidrug regimens at 1-2 mg/kg/day in pediatric patients 2, 1
HIV-Related Prophylaxis (Off-Label)
Pneumocystis jirovecii (carinii) pneumonia (PCP) prophylaxis: Alternative to trimethoprim-sulfamethoxazole in HIV-infected adults and children 2
- Daily dosing of 100 mg showed <1% PCP recurrence rate over 16 months for secondary prophylaxis in adults 2
- Weekly dosing (100-200 mg) demonstrated zero failure rate for primary prophylaxis and 8% recurrence for secondary prophylaxis 2
- Particularly useful in patients who cannot tolerate TMP-SMX, with approximately 60% of TMP-SMX-intolerant patients able to tolerate dapsone 2
- Provides added prophylactic benefit against PCP in HIV-positive patients with hidradenitis suppurativa requiring systemic antibiotics 2
Toxoplasmosis prophylaxis: When combined with pyrimethamine, provides protection in HIV-infected patients 2
Dermatologic Conditions (Off-Label)
- Acne vulgaris: Topical dapsone gel 5% is FDA-approved; oral dapsone has established efficacy but limited use due to systemic side effects 3
- Bullous pemphigoid 4
- Behçet's disease 4
- Lupus erythematosus 4
- Psoriasis 5
Other Conditions (Off-Label)
- Toxoplasma gondii infections 5
- Pneumocystis carinii pneumonia in AIDS patients (treatment, not just prophylaxis) 5
Important Clinical Considerations
Dosing Varies by Indication
- Leprosy in children: 1-2 mg/kg/day divided doses 2
- PCP prophylaxis in adults: 100 mg daily or 100-200 mg weekly 2
- PCP prophylaxis in children: 2 mg/kg dose, potentially twice or thrice weekly 6
Key Safety Monitoring Required
- G6PD deficiency screening mandatory before initiating therapy due to hemolysis risk 7
- Complete blood count and liver function tests needed for monitoring due to risks of hemolytic anemia, methemoglobinemia, neutropenia, and hepatotoxicity 7, 5
- Dose-related hemolysis most common when daily doses exceed 200 mg 2
Common Pitfalls
- Hepatotoxicity is underrecognized: Clinicians often focus on methemoglobinemia but should be aware of cholestatic injury and hepatic necrosis potential 5
- Drug interactions in HIV patients: Careful consideration needed when combined with protease inhibitors or other antiretrovirals 2
- Hypersensitivity syndrome ("sulfone syndrome"): Rare but serious reaction characterized by fever, exfoliative dermatitis, hepatic dysfunction, and methemoglobinemia occurring 1-4 weeks into therapy 2