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The plasma-paracetamol concentration may be difficult
to interpret when paracetamol
has been ingested over
several hours. If there is doubt about timing or the need
for treatment then the patient should be treated with an
antidote.
ACETYLCYSTEINE
Indications
paracetamol overdosage, see notes above
Cautions
asthma (see side-effects below but do not
delay acetylcysteine treatment)
Side-effects
hypersensitivity-like reactions managed
by reducing infusion rate or suspending until reaction
settled (rash also managed by giving antihistamine;
acute asthma managed by giving nebulised short-
acting beta
2
agonist)—contact the National Poisons
Information Service if reaction severe
Dose
. By intravenous infusion,
ADULT
and
CHILD
,
initially
150 mg/kg (max.
16.5 g) over 15 minutes,
then
50 mg/kg (max.
5.5 g) over 4 hours then 100 mg/kg
(max.
11 g) over 16 hours
Administration
Dilute requisite dose in glucose intravenous
infusion 5% as follows:
ADULT
and
CHILD
over 12 years,
initially 200 mL given over 15 minutes,
then 500 mL over 4
hours, then 1 litre over 16 hours;
CHILD
under 12 years, body-
weight over 20 kg,
initially 100 mL given over 15 minutes,
then 250 mL over 4 hours, then 500 mL over 16 hours;
CHILD
body-weight under 20 kg,
initially 3 mL/kg given over 15
minutes, then 7 mL/kg over 4 hours, then 14 mL/kg over 16
hours
Note
Manufacturer also recommends other infusion fluids,
but glucose 5% is preferable
Acetylcysteine
(Non-proprietary) A
Injection
,
acetylcysteine 200 mg/mL,
net price 10-
mL amp = £1.96
Parvolex
c
(UCB Pharma) A
Injection
,
acetylcysteine 200 mg/mL,
net price 10-
mL amp = £2.25
METHIONINE
Indications
paracetamol overdosage, see notes above
Hepatic impairment
may precipitate coma
Side-effects
nausea,
vomiting,
drowsiness,
irritability
Dose
.
ADULT
and
CHILD
over 6 years initially 2.5 g, followed by
3 further doses of 2.5 g every 4 hours,
CHILD
under 6
years initially 1 g,
followed by 3 further doses of 1 g
every 4 hours
Methionine
(Pharma Nord)
Tablets
,
f/c,
methionine 500 mg,
net price 20-tab
pack = £9.95
With paracetamol (co-methiamol)
Section 4.7.1
Analgesics (opioid)
Opioids (narcotic analgesics)
cause coma,
respiratory
depression,
and pinpoint
pupils.
The specific antidote
naloxone is indicated if
there is coma or bradypnoea.
Since naloxone has a shorter duration of
action than
many opioids, close monitoring and repeated injections
are necessary according to the respiratory rate and
depth of
coma.
When repeated administration of
nal-
oxone is required,
it can be given by continuous intra-
venous infusion instead and the rate of infusion adjusted
according to vital
signs.
The effects of
some opioids,
such as buprenorphine,
are only partially reversed by
naloxone.
Dextropropoxyphene and methadone have
very long durations of action;
patients may need to be
monitored for long periods following large overdoses.
Naloxone reverses the opioid effects of dextropropoxy-
phene;
the long duration of
action of
dextropropoxy-
phene calls for prolonged monitoring and further doses
of
naloxone may be required.
Norpropoxyphene,
a
metabolite of dextropropoxyphene, also has cardiotoxic
effects
which
may
require
treatment
with sodium
bicarbonate,
or magnesium sulphate,
or both;
arrhy-
thmias may occur for up to 12 hours.
The National
Poisons Information Service (Tel:
0844 892 0111) will provide specialist advice on all
aspects of poisoning day and night
NALOXONE HYDROCHLORIDE
Indications
overdosage with opioids; reversal of
opioid-induced respiratory depression and reversal of
neonatal respiratory depression resulting from opioid
administration to mother during labour (section
15.1.7)
Cautions
physical dependence on opioids;
cardiac
irritability; naloxone is short-acting,
see notes above
Pregnancy
section 15.1.7
Breast-feeding
section 15.1.7
Dose
. By intravenous injection,
0.4–2 mg;
if no response
repeat at intervals of 2–3 minutes to a max. of 10 mg
(then review diagnosis); further doses may be required
if respiratory function deteriorates;
CHILD
10 micr-
ograms/kg;
if no response give subsequent dose of
100 micrograms/kg (then review diagnosis);
further
doses may be required if respiratory function dete-
riorates
.
By subcutaneous
or
intramuscular injection,
ADULT
and
CHILD
dose as for intravenous injection but use
only if intravenous route not feasible (onset of action
slower)
. By continuous intravenous infusion using an infusion
pump, rate adjusted according to response (initial rate
may be set at 60% of initial intravenous injection dose
(see above) and infused over 1 hour)
Important
Doses used in acute opioid overdosage may not
be appropriate for the management of opioid-induced resp-
iratory depression and sedation in those receiving palliative
care and in chronic opioid use;
see also section 15.1.7 for
management of postoperative respiratory depression
1
Naloxone
(Non-proprietary) A
Injection
,
naloxone hydrochloride 20 micrograms/
mL,
net price 2-mL amp = £5.50;
400 micrograms/
mL,
1-mL amp = £4.10;
1 mg/mL,
2-mL prefilled
syringe = £8.36
1
Minijet
c
Naloxone
(UCB Pharma) A
Injection
,
naloxone hydrochloride 400 micrograms/
mL, net price 1-mL disposable syringe = £20.40, 2-mL
disposable syringe = £12.96, 5-mL disposable syringe
= £12.68
1.
A restriction does not apply where administration is for
saving life in emergency
36
Emergency treatment of poisoning
BNF 61
Emergency treatment of poisoning