Benzbromarone

CLINICAL USE

Treatment of hyperuricaemia, chronic gout and tophaceous gout

DOSE IN NORMAL RENAL FUNCTION

50–200 mg daily(Usual dose 50–100 mg daily)

PHARMACOKINETICS

  • Molecular weight                           :424.1
  • %Protein binding                           :>99
  • %Excreted unchanged in urine     : 6–18 (as metabolites)
  • Volume of distribution (L/kg)       :19 litres
  • half-life – normal/ESRD (hrs)      :2–4

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

    40–60 50–200 mg daily120–40 50–100 mg daily1<20 Avoid. Ineffective

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                :Avoid. Ineffective
  • HD                     :Avoid. Ineffective
  • HDF/high flux   :Avoid. Ineffective
  • CAV/VVHD      :Use with caution. Dose as in GFR=20–40 mL/min

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugsA

  • spirin and salicylates: antagonise uricosuric effects of benzbromarone
  • Anticoagulants: may enhance effect of warfarinPyrazinamide: antagonise uricosuric effects of benzbromarone
  • Hepatotoxic agents: enhanced hepatotoxicity

    ADMINISTRATION

    Reconstition

    Route

    Oral

    Rate of Administration

    Comments

    OTHER INFORMATION

    Monitor LFTs while on benzbromarone as can cause fulminant liver failure

  • As with other uricosurics, treatment with benzbromarone should not be started during an acute attack of gout
  • Maintain an adequate fluid intake to reduce the risk of uric acid renal calculi
  • Biological effect of 100 mg benzbromarone is equivalent to 1.5 g probenecid or greater than 300 mg of allopurinol.
  • Benzbromarone is considered unsafe in patients with acute porphyria
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