Avlosulfon (Dapsone)


Avlosulfon (Dapsone) is an oral medication used to treat a certain type of skin disorder (dermatitis herpetiformis). As an anti-infective medicine, it can sometimes be used for other purposes.

Indications And Clinical Uses

  • Leprosy;
  • Dermatitis herpetiformis;
  • Actinomycotic mycetoma.


Sulfones are contraindicated in patients with advanced amyloidosis of the kidneys.


Dapsone should be used with caution in patients with cardiac, pulmonary, hepatic or renal disease. Routine hematologic analysis should be carried out during long-term therapy with sulfones, because of the danger of hemolytic anemia. The hemolytic effect of sulfones may be exaggerated in glucose-6-phosphate dehydrogenase deficient individuals.

Drug Interactions

Rifampicin has been reported to increase the plasma clearance of dapsone, and probenecid has been reported to decrease excretion of dapsone. Administration of dapsone with chloroquine and/or primaquine may lead to an increase of methemoglobin levels in individuals predisposed to methemoglobinemia.

Reaction States: Leprosy patients receiving effective chemotherapy may suffer episodes of acute or chronic inflammation. Generally, antileprosy chemotherapy should be continued unchanged but these reactions must be adequately treated since they may result in crippling deformity.

Nonlepromatous Lepra Reactions: Complications may include severe peripheral neuritis with accompanying cutaneous sensory loss and paralysis. In the management of acute neuritis corticosteroids may be considered.

Lepromatous Lepra Reactions: Complications may include neuritis, an increase in muscle weakness, lymphadenitis, iridocyclitis, orchitis and more rarely nephritis and large-joint arthritis. In the management of these reactions, corticosteroids, and clofazimine may be considered.

Adverse Reactions

Most adverse reactions are dose-related and uncommon at dosages up to 100 mg daily. They include anorexia, nausea, vomiting, headache, dizziness, tachycardia, nervousness, insomnia and skin disorders. Agranulocytosis, peripheral neuritis and psychosis have also been reported. Varying degrees of dose-related hemolysis and methemoglobinemia occur in most individuals given more than 200 mg daily. Dosages up to 100 mg daily are unlikely to cause hemolysis, but individuals with glucose-6-dehydrogenase deficiency may be affected by dosages above 50 mg daily. Rare reactions include the “dapsone syndrome” and hypoalbuminemia.

The “dapsone syndrome” is hypersensitivity reactions which develop rarely and tend to occur during the first 6 weeks of therapy. Symptoms may include fever, eosinophilia, mononucleosis, lymphadenopathy, leukopenia, jaundice with hepatitis, and exanthematous skin eruptions which may progress to exfoliative dermatitis, toxic epidermal necrolysis, or Stevens-Johnson syndrome. Although patients usually improve if dapsone is withdrawn fatalities have occurred. Fixed drug eruptions occur in dark-skinned people. Although agranulocytosis has been reported rarely for dapsone when used alone, reports have been more common when the drug has been used with other agents in the prophylaxis of malaria. Other miscellaneous reactions such as peripheral neuropathy, nephrotic syndrome and renal papillary necrosis have been reported.

Pregnancy and Lactation

The sulfone drugs are generally contraindicated in pregnancy and therefore the use of dapsone during pregnancy should be avoided unless, in the judgment of the physician, potential benefit outweighs the risk. Dapsone in high doses has been reported to be carcinogenic in rats and mice, but negative in salmonella mutagenicity assays. The relevance of this finding to human exposure is unclear. Dapsone is excreted in breast milk in therapeutic amounts. Sulfones may cause hemolytic anemia in glucose-6-phosphate dehydrogenase deficient neonates.

Symptoms And Treatment Of Overdose

Symptoms and Treatment: In cases of severe overdosage the stomach should be emptied by aspiration and lavage. There is no specific antidote and therefore treatment should be symptomatic e.g., i.v. methylene blue 1 to 2 mg/kg body weight, i.v. ascorbic acid 0.5 to 1 g and oxygen for the methemoglobinemia plus general supportive measures. The repeated administration of activated charcoal has been reported to increase the elimination rate of dapsone and its metabolite following overdosage.

If someone has overdosed and has severe symptoms such as trouble breathing or fainting, call 911. Otherwise, call a poison control center at 1-800-222-1222 right away (US residents).

Dosage And Administration

Take Avlosulfon by mouth with or without food, usually once daily or as directed by a health professional.

Leprosy: Adults: The standard dose is 100 mg daily (1 to 2 mg/kg body weight).

Children: Dosage should be adjusted according to body weight.

The modern treatment of leprosy involves the use of multiple drug regimens to avoid the development of resistant strains. The World Health Organization has made the following recommendations for standard adult treatment regimens (with dosage adjustments according to body weight): Multibacillary leprosy: rifampicin: 600 mg once-monthly, supervised; dapsone: 100 mg daily, self-administered; clofazimine: 300 mg once-monthly, supervised and 50 mg daily, self-administered.

Paucibacillary Leprosy: rifampicin: 600 mg once a month for 6 months, supervised; dapsone: 100 mg daily for 6 months, self-administered.

Further information on treatment regimens is contained in “Chemotherapy of Leprosy for Control Programmes” W.H.O. Technical Report Series 675 (1982).

Dermatitis Herpetiformis: Adults: The usual maintenance dosage is 50 to 100 mg daily, but as little as 50 mg weekly may be adequate. Dosages of up to 300 mg daily may be considered, but efforts should be made to reduce this to the minimal maintenance dosage as soon as possible.

Actinomycotic Mycetoma: Adults: Published reports suggest that a dose of 100 mg should be given twice daily and continued for some months after the clinical symptoms have disappeared.


Store at room temperature. Protect from light. Keep away from children and pets.


IMPORTANT: This is a summary and does NOT have all possible information about this medicine. This information does not assure that this medicine is safe or appropriate for you. This information cannot be used as a substitute for medical advice. Consult your health care provider if you have any health condition. Always ask your health care provider for complete information about this medicine and your individual health needs.

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