dapsone

Dapsone is a medication used to treat leprosy, a chronic infectious disease caused by Mycobacterium leprae, a type of slow-growing bacteria, and dermatitis herpetiformis, an itchy blistering skin condition caused by celiac disease, an autoimmune gastrointestinal inflammatory condition triggered by gluten.

Dapsone works by preventing bacterial growth in leprosy, while it works as an anti-inflammatory and immunomodulatory agent in the treatment of dermatitis herpetiformis.

Dapsone arrests the growth of bacteria by inhibiting the synthesis of folic acid that they require to survive and grow. In the treatment of skin conditions, dapsone inhibits the activity of neutrophils, types of immune cells that are inflammatory, damage skin tissue and cause lesions. Neutrophils release free radicals to kill pathogens, which also damage tissue in the affected region. Dapsone reduces neutrophil-induced damage in skin lesions.

The uses of dapsone include:

Adults

FDA-approved:

• Leprosy (adults and children)
• Dermatitis herpetiformis

Off-label:

• Severe aphthous ulcers
• Bullous systemic lupus erythematosus
• Immune thrombocytopenia
• Pemphigus vulgaris
• Pyoderma gangrenosum
• Relapsing polychondritis
• Pneumocystis (Carinii) Jiroveci (adults and children)
• Pneumocystis pneumonia prophylaxis in patients with HIV
• Pneumocystis pneumonia treatment in patients with HIV
• Toxoplasma gondii encephalitis prophylaxis in patients with HIV

• Do not take dapsone if you are hypersensitive to any of the components in the formulation.
• Dapsone can cause blood disorders including anemia and agranulocytosis. Monitor patients closely.
• Patients with severe anemia should first be treated for anemia before initiating dapsone therapy.
• Dapsone may destroy red cells and the reduced survival time of red cells may result in artificially lower HbA1c values.
• Prolonged dapsone treatment may lead to fungal and bacterial superinfections, including Clostridium difficile-associated diarrhea and pseudomembranous colitis.
• Use with caution in hemoglobin M deficiency.
• Use with caution in patients with hypersensitivity to sulfonamides.
• Dapsone may cause peripheral neuropathy or severe skin reactions such as toxic epidermal necrolysis.

Common side effects of dapsone include:

• Methemoglobinemia, a condition with excessive blood levels of methemoglobin, a form of hemoglobin that does not deliver oxygen to tissues
• Low red blood cell count due to rapid destruction (hemolytic anemia)
• Low blood count of neutrophil immune cells (neutropenia)
• Severely low count of granulocyte immune cells (agranulocytosis)
• Increase in immature red cell count (reticulocytosis)
• Abdominal pain
• Nausea
• Vomiting
• Rapid heart rate (tachycardia)
• Kidney disorders including:
  • Nephrotic syndrome
  • Renal papillary necrosis
• Excessive albumin excretion in urine (albuminuria)
• Low blood albumin levels (hypoalbuminemia)
• Male infertility
• Infectious mononucleosis
• Headache
• Vertigo
• Insomnia
• Psychomotor impairment
• Psychosis
• Blurred vision
• Ringing in the ears (tinnitus)
• Lupus-like syndrome

Less common side effects of dapsone include:

• Blood disorders including
  • Anemia due to lack of red cell production (aplastic anemia)
  • Decreased hemoglobin
  • Low count of all types of blood cells (pancytopenia)
• Pancreas inflammation (pancreatitis)
• Liver injury
• Liver inflammation (hepatitis)
• Jaundice due to impaired bile flow (cholestatic jaundice)
• Increase in levels of liver enzyme (transaminases)
• Increased bilirubin levels in blood (hyperbilirubinemia)
• Acute kidney injury
• Peripheral nerve damage (neuropathy)
• Fever
• Hypersensitivity skin reactions including:
  • Phototoxicity
  • Maculopapular rash
  • Fixed drug eruptions
  • Acute generalized exanthematous pustulosis (AGEP)
  • Toxic epidermal necrolysis
  • Stevens-Johnson syndrome
• Drug reaction with eosinophilia and systemic symptoms (DRESS)
• Lung inflammation due to eosinophilia (eosinophilic pneumonitis)

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Tablet

• 25 mg
• 100 mg

Adult:

Dermatitis Herpetiformis

• 50 mg orally once daily, titrate to 300 mg once daily or higher to achieve desired effect
• Reduce dose to minimum effective dose within the range of 50-300 mg once daily as soon as possible

Leprosy

• 100 mg orally once daily, in combination with other antileprosy drugs

Tuberculoid or Lepromatous Disease

• 100 mg orally once daily with rifampin 600 mg orally once daily

Pneumocystis (Carinii) Jiroveci (Off-label)

Prophylaxis

• 100 mg orally once daily or divided twice daily as monotherapy, OR
• 50 mg orally once daily in combination with weekly pyrimethamine and leucovorin

Treatment

• 100 mg orally once daily in combination with trimethoprim for 21 days

Pediatric:

Leprosy

• 1-2 mg/kg orally once daily; not to exceed 100 mg/day in combination with other antileprosy agents  

Dosing considerations

• Administer for 3 years (minimum) in combination with multidrug regimen (i.e., rifampin)

Pneumocystis (Carinii) Jiroveci (Off-label)

Prophylaxis

• Children above 1 month old: 2 mg/kg orally once daily; not to exceed 100 mg/day, OR  
• 4 mg/kg/dose orally once a week; not to exceed 200 mg/week
• Adolescents: 100 mg orally once daily or divided twice daily as monotherapy, OR 50 mg orally once daily in combination with weekly pyrimethamine and leucovorin

Treatment

• Children above 1 month old: 2 mg/kg orally once daily in combination with trimethoprim for 21 days
• Adolescents: 100 mg orally once daily in combination with trimethoprim for 21 days

Overdose

• Dapsone overdose may result in methemoglobinemia, which may be treated with vitamin E and C, cimetidine, or intravenous (IV) methylene blue.

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Dapsone has no known severe interactions with other drugs.
• Serious interactions of dapsone include:
  • abametapir
  • aluminum hydroxide
  • apalutamide
  • BCG vaccine live
  • calcium carbonate
  • dapsone topical
  • famotidine
  • fexinidazole
  • ibuprofen/famotidine
  • idelalisib
  • ivosidenib
  • lansoprazole
  • sodium bicarbonate
  • sodium citrate/citric acid
• Dapsone has moderate interactions with at least 52 different drugs.
• Dapsone has mild interactions with at least 77 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider about all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or healthcare provider if you have any questions about the medication.

• Studies indicate dapsone does not affect female reproductive capacity, but can cause male infertility.
• Dapsone should be used during pregnancy only if clearly needed and potential maternal benefits outweigh possible fetal risks. Dapsone may increase bilirubin levels in the newborn and the associated risk of brain damage (kernicterus). There also have been reports of hemolytic anemia in the fetus/infant.
• Dapsone is excreted in breastmilk. The decision should be made to discontinue nursing or dapsone, based on the importance of the treatment to the mother, because of the potential for serious adverse reactions in the breastfed infant.

• Take dapsone exactly as prescribed.
• You will need to undergo periodic tests while on treatment. Do not miss your appointments and follow up with your doctor.
• Inform your physician immediately if you develop:
  • Symptoms of infection
  • Easy bruising or bleeding
  • Liver injury symptoms such as jaundice, abdominal pain, and dark urine
• Dapsone may cause diarrhea that can develop even up to two months after the last dose. Notify your physician if you have watery or bloody stools, with or without stomach cramps and fever.
• Store safely out of reach of children.
• In case of overdose, seek medical help or contact Poison Control.