Dapsone

MECHANISM OF ACTIONS:

PHARMACOKINETICS:
  • Dose of Dapsone is 1-2 mg/kg
  • Absorption: It is completely absorbed after oral administration
  • Distribution:Approximately 70% bound to plasma protein. The main metabolite, monoacetyl dapsone, is nearly 100% protein bound.
  • Metabolism:Dapsone is acetylated in the liver, the degree of which is genetically determined.
  • Elimination:
  1. Metabolites are excreted in bile & urine
  2. Elimination takes 1-2 weeks or longer
  3. The plasma t1/2 is variable, though often>24hrs
USES:
  • Mycobacterium leprae infections (leprosy)./hansen’s disease 
  • WHO regime for paucibacillary leprosy is 100 mg Dapsone daily + Rifampcin monthly (600 mg)
  • Acne.
  • Pneumocystis pneumonia.
  • Generalised lichen planus
  • Dermatitis Herpetiformis.
  • Toxoplasmosis - Prophylaxis
DRUG INTERACTIONS:
  • Folic acid antagonists (such as pyrimethamine), nitrofurantoin, primaquine.
  • This medication may decrease the effectiveness of combination-type birth control pills.
ADVERSE ACTION:
  • Mild haemolytic anaemia
  • Gastric intolerance-nausea & anorexia
  • methaemoglobinaemia, headache, paresthesias, mental symptoms & drug fever
  • allergic rashes, fixed drug eruption, hypermelanosis, phototoxicity& rarely exfoliative dermatitis
  • Hepatitis & agranulocytosis
  • Dapsone reaction/sulfone syndrome
Exam Question
  • Dapsone is used in the treatment and therapeutic diagnosis of dermatitis herpetiformis
  • Both Dapsone & Systemic steroids drugs is used in generalised lichen planus
  • Rifampicin, dapsone and clofazimine are used if HIV infected patient develops multibacillary leprosy.
  • Hemolytic anemia is the Commonest side effect of Dapsone
  • Dose of Dapsone is 1-2 mg/kg
  • WHO regime for paucibacillary leprosy is 100 mg Dapsone daily + Rifampcin monthly (600 mg)
  • Fixed drug eruption (FDE) is an adverse cutaneous reaction to an ingested dapsone
Don't Forget to Solve all the previous Year Question asked on Dapsone