Drug Characteristics
  • Formulation

    Tablets: 50mg, 100mg

  • Dose

    PCP treatment: 100 mg orally once a day (in combination with trimethoprim) for 14–21 days

    PCP prophylaxis: 50–100 mg orally once a day

    When used with pyrimethamine (50–75 mg) once weekly protects against toxoplasmosis        

  • Side Effects

    Haemolytic anaemia, methaemoglobinaemia, peripheral neuropathy, rash, dapsone syndrome (rash with fever and eosinophilia) – discontinue treatment immediately, hepatitis, agranulocytosis

  • Interactions

    Additive toxicity with other drugs causing peripheral neuropathy e.g. isoniazid, stavudine

    Antacids and didanosine tablets prevent absorption (dapsone requires an acidic pH for absorption)

    Excretion of dapsone is reduced and plasma concentrations are increased by concurrent administration of probenecid.

    Rifampicin has been reported to increase the plasma clearance of dapsone

  • Renal

    GFR 20–50: Dose as in normal renal function

    GFR 10–20: Dose as in normal renal function, use with caution

    GFR<10: 50–100 mg daily, use with caution        

  • Hepatic

    No data on dosage reduction

    Use with caution        

  • Pregnancy

    Compatible – Maternal Benefit >> Embryo-Foetal Risk

  • Other Information