HEALTHY LIFESTYLE




Allopurinol
Allopurinol.JPG

Allopurinol

CLINICAL USE

  • Gout prophylaxis
  • Hyperuricaemia

    DOSE IN NORMAL RENAL FUNCTION

    100–900 mg/day (usually 300 mg/day) Doses above 300 mg should be given in divided doses

    PHARMACOKINETICS

  • Molecular weight                           : 136.1
  • %Protein binding                           : <5
  • %Excreted unchanged in urine     :
  • <10           :
  • Volume of distribution (L/kg)       : 1.6
  • half-life – normal/ESRD (hrs)      : 1–2/Increased

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

  • 20 to 50     : 200–300 mg daily
  • 10 to 20     : 100–200 mg daily
  • <10           : 100 mg daily or 100 mg on alternate days

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                : Dialysed. 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      : Dialysed. Dose as in GFR=10– 20 mL/min

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugs
  • ACE inhibitors: increased risk of toxicity with captopril
  • Ciclosporin: isolated reports of raised ciclosporin levels (risk of nephrotoxicity)
  • Cytotoxics: effects of azathioprine and mercaptopurine enhanced with increased toxicity; avoid concomitant use with capecitabine

    ADMINISTRATION

    Reconstition

    Route

    Oral

    Rate of Administration

    Comments

  • In all grades of renal impairment commence with 100 mg/day and increase if serum and/or urinary urate response is unsatisfactory. Doses less than 100 mg/day may be required in some patients
  • Take as a single daily dose, preferably after food

    OTHER INFORMATION

    A parenteral preparation is available from Glaxo Wellcome on a named patient basis
  • HD patients may be given 300 mg post dialysis, i.e. on alternate days
  • Increased incidence of skin rash in patients with renal impairment
  • Efficient dialysis usually controls serum uric acid levels If a patient is prescribed azathioprine or 6-mercaptopurine concomitantly, reduce azathioprine or 6-mercaptopurine dose by 66–75%
  • Main active metabolite: oxipurinol – renally excreted; plasma protein binding 17%; half-life: Normal/ESRF = 13– 30/>125 hours – 1 week
  • other drugs