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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