Acetylcysteine

CLINICAL USE

  • Treatment of paracetamol overdose
  • Renal protection during radiological scans involving contrast media (unlicensed)

    DOSE IN NORMAL RENAL FUNCTION

    IV infusion

    : Initially 150 mg/kg in 200 mL glucose 5% over 15 minutes, followed by 50 mg/kg in 500 mL glucose 5% over 4 hours, then 100 mg/kg in 1000 mL over 16 hours

  • Renal protection – see ‘Other Information’

    PHARMACOKINETICS

  • Molecular weight                           :163.2
  • %Protein binding                           :50
  • %Excreted unchanged in urine     : 20–30
  • Volume of distribution (L/kg)       :0.33–0.47
  • half-life – normal/ESRD (hrs)      :2–6/–

    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
  • <10           : Dose as in normal renal function. See ‘Other Information’

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD                :Likely to be Dialysed. Dose as in normal renal function
  • HD                     :Dialysed. Dose as in normal renal function
  • HDF/high flux   :Dialysed. Dose as in normal renal function
  • CAV/VVHD      :Likely to be Dialysed. Dose as in normal renal function

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugsNone known

    ADMINISTRATION

    Reconstition

    Glucose 5%

    Route

    IV, PO (PO route unlicensed in the UK)

    Rate of Administration

    See under Dose

    Comments

  • Children should be treated with the same doses and regimen as adults; however, the quantity of IV fluid should be modified to account for age and weight
  • Acetylcysteine has been administered neat or in a 1 to 1 dilution using an infusion pump. These are unlicensed methods of administration
  • Minimum dilutions can range from 100–250 mL. It is advised to give strong solutions centrally. (UK Critical Care Group, Minimum Infusion Volumes for fluid restricted critically ill patients, 3rd Edition, 2006)

    OTHER INFORMATION

  • Bennett recommends administering 75% of dose for patients with severe renal impairment; however, Evans Medical does not recommend a dose reduction and, from its records, neither does the National Poisons Centre
  • There is some evidence that acetylcysteine may have a renoprotective effect during scans involving the use of contrast media, in patients with already impaired renal function
  • Dose = 600 mg PO BD the day before the scan, repeated the day of the scan, together with IV or PO fluids. Injection may be taken orally, or tablets are available from IDIS
  • Alternatively, give 1 g acetylcysteine IV in 500 mL sodium chloride 0.9% or dextrose 5%, the day before the scan, repeated the day of the scan
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