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Patients at
high-risk
of liver damage include those:
.
taking liver
enzyme-inducing drugs
(e.g.
carba-
mazepine, phenobarbital, phenytoin, primidone, rif-
ampicin,
rifabutin,
efavirenz,
nevirapine,
alcohol
and St John’s wort);
.
who are malnourished (e.g.
in anorexia or bulimia,
cystic fibrosis,
hepatitis C,
in alcoholism,
or those
who are HIV-positive);
.
who have not eaten for a few days.
These patients can develop toxicity at
lower plasma-
paracetamol concentration and should be treated if the
concentration is
above the
high-risk treatment
line
(which joins plots that are at 50% of
the plasma-para-
cetamol concentrations of the normal treatment line).
The prognostic accuracy of
plasma-paracetamol
con-
centration taken after
15 hours
is
uncertain,
but
a
concentration above the relevant treatment line should
be regarded as carrying a serious risk of liver damage.
Patients whose plasma-paracetamol concentrations are above the normal treatment line should be treated with
acetylcysteine by intravenous infusion (or, if acetylcysteine cannot be used, with methionine by mouth, provided
the overdose has been taken within 10–12 hours and the patient is not vomiting).
Patients at high-risk of liver damage include those:
.
taking liver enzyme-inducing drugs (e.g. carbamazepine, phenobarbital, phenytoin, primidone, rif-
ampicin, rifabutin, efavirenz, nevirapine, alcohol, St John’s wort);
.
who are malnourished (e.g. in anorexia or bulimia, cystic fibrosis, hepatitis C, in alcoholism, or those who
are HIV-positive);
.
who have not eaten for a few days.
These patients should be treated if their plasma-paracetamol concentration is above the high-risk treatment
line.
The prognostic accuracy after
15 hours is uncertain but
a plasma-paracetamol
concentration above the
relevant treatment line should be regarded as carrying a serious risk of liver damage.
Graph reproduced courtesy of University of Wales College of Medicine Therapeutics and Toxicology Centre
BNF 61
Emergency treatment of poisoning
35
Emergency treatment of poisoning