See Available Brands of Dapsone in India

P - Caution when used during pregnancy
L - Caution when used during lactation

Dapsone (diamino-diphenyl sulfone) is a pharmacological medication most commonly used in combination with rifampicin and clofazimine as multidrug therapy (MDT) for the treatment of Mycobacterium leprae infections (leprosy). It is also used to treat Pneumocystis carinii pneumonia (PCP) caused by Pneumocystis jiroveci (formerly P. carinii). Dapsone is used in combination with pyrimethamine in the treatment of malaria.

Pharmacodynamics

Pharmacokinetics

Dapsone inhibits folic acid synthesis by preventing normal bacterial utilization of PABA (PABA).

Absorption

Completely absorbed from the GI tract (oral); peak plasma concentrations after 2-8 hr.

Distribution

Saliva, crosses the placenta and enters breast milk. Protein-binding: 50-80% (plasma proteins); 100% (monoacetylated metabolite).

Metabolism

Acetylated to monoacetyldapsone (major metabolite and other mono and diacetyl derivatives); hydroxylation (to hydroxylamine dapsone); undergoes enterohepatic recycling.

Excretion

Via urine (20% as unchanged drug).

Dapsone Indications / Dapsone Uses

Information Not Available

Dapsone Adverse Reactions / Dapsone Side Effects

Anaemia, peripheral neuropathy, haemolysis and methaemoglobinaemia (dose-related), nephrotic syndrome, psychological changes, hepatitis. Others: Nausea, vomiting, anorexia, headache, maculopapular rash, toxic epidermal necrolysis, Stevens-Johnson syndrome. Potentially Fatal: Agranulocytosis, serious cutaneous hypersensitivity reactions, exfoliative dermatitis.

Precautions

Monitor

Ensure that CBC and differential are performed and eva luated prior to starting therapy, weekly for the first month of therapy, then monthly for 6 mo, and every 6 mo thereafter during treatment.

Overdosage

Symptoms: nausea, vomiting, hyperexcitability (within a few min to up to 24 hr later), methemoglobin-induced depression, haemolysis (7-14 days after ingestion), seizures and severe cyanosis. Treatment: activated charcoal (20g four times daily) and haemolysis may enhance elimination of dapsone and its monoacetyl derivative. For patients without G6PD deficiency, methemoglobinemia may be treated with methylene blue 1-2 mg/kg given by slow IV injection (repeated if methemoglobin reaccumulates) or in less severe cases, 3-5 mg/kg every 4-6 hr orally.

Special Precautions

G6PD deficiency, methaemoglobin or Hb M. Perform regular blood counts and monitor liver function regularly. Pregnancy and lactation.

Other Drug Interactions

Decreased serum conc of dapsone when used with rifampicin. Increased plasma conc with probenecid, trimethoprim. Antagonize clofazimine.

Other Interactions

Information Not Available

Dosage

Oral

Primary and secondary prophylaxis of pneumocystis pneumonia Adult: 50 mg daily, with pyrimethamine 50 mg once wkly. Alternatively, 100 mg with pyrimethamine 50 mg twice wkly. Child: 1 mth-18 yr: 2 mg/kg daily (max: 100 mg daily) or 4 mg/kg wkly (max: 200 mg wkly).

Oral

Multibacillary leprosy Adult: 100 mg daily with clofazimine 50 mg daily, together with rifampicin 600 mg and clofazimine 300 mg once a mth for 12 mth. <35 kg: dapsone dose: 1-2 mg/kg/day. Child: and child 10-14 yr old: daily doses of dapsone 50 mg, or 1 to 2 mg/kg if their body-weight is low

Oral

Paucibacillary leprosy Adult: 100 mg daily with 600 mg rifampicin once a mth, both given for 6 mth. Child: Reduce dose as for multibacillary leprosy.

Oral

Dermatitis herpetiformis Adult: Initially, 50 mg daily increased gradually to 300 mg daily if required.

Food(before/after)

Should be taken with food

List of Contraindications

Dapsone and Pregnancy

Caution when used during pregnancy

Category C: Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Dapsone and Lactation

Caution when used during lactation

Dapsone and Children

Oral

Children are treated on the same schedule as adults, but with correspondingly smaller doses. Dapsone is generally not considered to have an effect on the later growth and functional development of children.

Topical

Safety and efficacy not established in children younger than 12 yr of age.

Dapsone and Geriatic

Information Not Available

Dapsone and Other Contraindications

Hypersensitivity. Severe anaemia, porphyria

Storage

Oral

Store at 15-30

Lab interference

Information Not Available