Dapsone.JPG

Dapsone

CLINICAL USE

Treatment and prophylaxis of leprosy Dermatitis herpetiformis Pneumocystis jiroveci pneumonia (PCP)Malaria prophylaxis

DOSE IN NORMAL RENAL FUNCTION

Leprosy: 1–2 mg/kg or 100 mg daily PCP: 100 mg daily in 1 or 2 divided doses Dermatitis herpetiformis: 50–300 mg daily Malaria prophylaxis: 100 mg weekly in combination with pyrimethamine 12.5 mg weekly

PHARMACOKINETICS

  • Molecular weight                           :248.3
  • %Protein binding                           :50–80
  • %Excreted unchanged in urine     : 20
  • Volume of distribution (L/kg)       :1–1.5
  • half-life – normal/ESRD (hrs)      :10–80

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

  • 20 to 50     : Dose as in normal renal function
  • 10 to 20     : Dose as in normal renal function, use with caution
  • <10           : 50–100mg daily, use with caution. No dose reduction is required for malaria prophylaxis.

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                :Likely dialysability. Dose as in GFR <10 mL/min
  • HD                     :Dialysed. Dose as in GFR
  • <10           : mL/min
  • HDF/high flux   :Dialysed. Dose as in GFR
  • <10           : mL/min
  • CAV/VVHD      :Likely dialysability. Dose as in GFR 10 to 20 mL/min

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugsNone known

    ADMINISTRATION

    Reconstition

    Route

    Oral

    Rate of Administration

    Comments

    OTHER INFORMATION

    Greater risk of haemolytic side effects in patients with glucose-6-phosphate-dehydrogenase deficiencyRegular blood counts are recommended in patients with severe anaemia or renal impairment: weekly for the 1st month, then monthly for 6 months, then semi-annuallyAlmost all patients lose 1–2 g of haemoglobinThe dose for herpetiformis can be reduced if the patient is on a gluten free diet One study used dapsone in a haemodialysis patient for bullous dermatosis: therapy was initiated at 100 mg but the dose had to be reduced to 50 mg due to haemolytic effects.