Administration
Dapsone is administered orally. For administration to children, commercially available tablets of dapsone have been crushed and dissolved in strawberry syrup; however, studies evaluating bioavailability of the drug following administration of this preparation have not been published to date.
Dosage
Leprosy
For the treatment of multibacillary leprosy, the World Health Organization (WHO) recommends that adults receive dapsone in a dosage of 100 mg daily in conjunction with rifampin (600 mg once monthly) and clofazimine (50 mg once daily and 300 mg once monthly) given for 12 months.
Children 10-14 years of age with multibacillary leprosy should receive dapsone in a dosage of 50 mg daily in conjunction with rifampin (450 mg once monthly) and clofazimine (50 mg every second day and 150 mg once monthly) given for 12 months, and children younger than 10 years of age should receive an appropriately adjusted dosage (e.g., dapsone [25 mg daily], in conjunction with rifampin [300 mg monthly] and clofazimine [50 mg twice weekly and 100 mg once monthly]) given for 12 months.
The WHO recommends supervised administration of some drug doses included in the regimen (e.g., once-monthly doses). While the 12-month regimen is adequate for most patients with multibacillary leprosy, the WHO recommends that multibacillary leprosy patients with a high bacteriologic index who demonstrate no improvement (with evidence of worsening) of leprosy following completion of the initial 12 months of treatment should receive an additional 12 months of therapy.
If a patient with multibacillary leprosy experiences severe adverse effects related to dapsone, the drug may be discontinued from the regimen and therapy continued with rifampin and clofazimine given in the usually recommended dosages.
For the treatment of paucibacillary leprosy, the WHO recommends that adults receive dapsone in a dosage of 100 mg daily in conjunction with rifampin (600 mg once monthly) given for 6 months. Children 10-14 years of age with paucibacillary leprosy should receive dapsone in a dosage of 50 mg daily given in conjunction with rifampin (450 mg once monthly) for 6 months, and children younger than 10 years of age should receive an appropriately adjusted dosage (e.g., dapsone [25 mg daily] in conjunction with rifampin [300 mg once monthly]) given for 6 months.
If a paucibacillary leprosy patient experiences severe adverse effects related to dapsone, dapsone may be discontinued from the regimen and clofazimine substituted (given in the dosage recommended for the treatment of multibacillary leprosy) for a period of 6 months.
Dermatitis Herpetiformis
Dosage of dapsone for the treatment of dermatitis herpetiformis must be individually titrated to find the daily dosage that most effectively controls pruritus and lesions; daily dosage should then be reduced as soon as possible to a minimum maintenance level.
Dosage in adults is usually initiated with 50 mg daily; if full control is not achieved within the range of 50-300 mg daily, higher dosage may be tried. Maintenance dosage in adults generally ranges from 25-400 mg daily.
For the treatment of dermatitis herpetiformis in children, correspondingly smaller doses of dapsone are used. Occasional new lesions (3 or 4 per week) may occur during maintenance therapy with dapsone and are not generally an indication for altering maintenance dosage of the drug. Maintenance dosage of dapsone can often be reduced in patients who have adhered to a gluten-free diet for 6 months or longer.
Pneumocystis jiroveci (Pneumocystis carinii) Pneumonia Treatment
For the treatment of Pneumocystis jiroveci (formerly Pneumocystis carinii) pneumonia (PCP) in adults, dapsone is given in a dosage of 100 mg once daily in conjunction with trimethoprim (5 mg/kg 3 times daily) for 21 days.
Prevention
Various dosage regimens of dapsone have been recommended for primary prophylaxis against PCP or for long-term suppressive or chronic maintenance therapy (secondary prophylaxis) to prevent recurrence of PCP in HIV-infected adults and adolescents, including daily administration of dapsone alone, daily administration of dapsone in conjunction with weekly administration of pyrimethamine (with leucovorin), or weekly administration of dapsone and pyrimethamine (with leucovorin).
When dapsone is administered alone in HIV-infected adults and adolescents for primary or secondary PCP prophylaxis, the Prevention of Opportunistic Infections Working Group of the US Public Health Service and the Infectious Diseases Society of American (USPHS/IDSA) and other clinicians recommend a dosage of 50 mg twice daily or 100 mg once daily. Alternatively, the USPHS/IDSA and other clinicians state that these individuals can receive a dapsone dosage of 50 mg once daily in conjunction with pyrimethamine (50 mg once weekly) and oral leucovorin (25 mg once weekly) or a dapsone dosage of 200 mg once weekly in conjunction with pyrimethamine (75 mg once weekly) and oral leucovorin (25 mg once weekly).
For primary or secondary prophylaxis against PCP in HIV-infected infants and children 1 month of age or older, dapsone can be administered in a once-daily or once-weekly regimen.
When dapsone is administered daily for primary or secondary prophylaxis, the USPHS/IDSA, AAP, and other clinicians recommend that children 1 month of age or older receive 2 mg/kg (maximum 100 mg) once daily.
Alternatively, these children can receive dapsone in a dosage of 4 mg/kg (maximum 200 mg) once weekly. Current evidence indicates that primary or secondary PCP prophylaxis can be discontinued in certain adults and adolescents responding to potent antiretroviral therapy who have a sustained increase in CD4+ T-cell counts from less than 200/mm3 to greater than 200/mm3. (See Prophylaxis under Uses: Pneumocystis jiroveci [Pneumocystis carinii] Pneumonia.) However, the safety of discontinuing primary or secondary PCP prophylaxis in HIV-infected children receiving potent antiretroviral therapy has not been extensively studied to date.
Toxoplasmosis Prevention
For primary prophylaxis against toxoplasmosis in HIV-infected adults and adolescents, the USPHS/IDSA recommends a dapsone dosage of 50 mg once daily in conjunction with pyrimethamine (50 mg once weekly) with oral leucovorin (25 mg once weekly). Alternatively, the USPHS/IDSA states that HIV-infected adults and adolescents can receive a dapsone dosage of 200 mg once weekly in conjunction with pyrimethamine (75 mg once weekly) and oral leucovorin (25 mg once weekly).
For primary prophylaxis of toxoplasmosis in HIV-infected children 1 month of age or older, the USPHS/IDSA recommends a dapsone dosage of 2 mg/kg or 15 mg/m2 (maximum 25 mg) once daily in conjunction with pyrimethamine (1 mg/kg once daily) with oral leucovorin (5 mg once every 3 days). Limited data suggest that primary prophylaxis against toxoplasmosis can be discontinued in certain adults and adolescents whose CD4+ T-cell count increases to greater than 200/mm3 in response to potent antiretroviral therapy.
However, the safety of discontinuing primary toxoplasmosis prophylaxis in HIV-infected children receiving potent antiretroviral therapy has not been extensively studied to date.