page53
Body temperature
Hypothermia may develop in patients of
any age who
have been deeply unconscious for some hours, particu-
larly following overdose with barbiturates or phenothi-
azines.
It
may be missed unless core temperature is
measured using a low-reading rectal thermometer or by
some other means. Hypothermia should be managed by
prevention of
further
heat
loss
and appropriate re-
warming as clinically indicated.
Hyperthermia
can develop in patients
taking
CNS
stimulants;
children and the elderly are also at
risk
when taking therapeutic
doses
of
drugs
with anti-
muscarinic properties.
Hyperthermia is initially mana-
ged by removing all
unnecessary clothing and using a
fan.
Sponging with tepid water will
promote evapora-
tion. Advice should be sought from the National Poisons
Information Service
on the
management
of
severe
hyperthermia resulting from conditions
such as
the
serotonin syndrome.
Both hypothermia and hyperthermia require urgent
hospitalisation for assessment and supportive treatment.
Convulsions
Single short-lived convulsions do not require treatment.
If convulsions are protracted or recur frequently, loraze-
pam 4 mg or diazepam (preferably as emulsion) 10 mg
should be given by slow intravenous injection into a
large vein (section 4.8.2).
Benzodiazepines should not
be given by the intramuscular route for convulsions.
If
the intravenous route is not readily available, diazepam
can be administered as a rectal
solution or midazolam
[unlicensed use]
can be given by the buccal
route
(section 4.8.2).
Removal and elimination
Prevention of absorption
Given by mouth,
activated charcoal
can bind many
poisons in the gastro-intestinal
system,
thereby
redu-
cing their absorption
.
The sooner it is given the more
effective it is,
but it may still
be effective up to 1 hour
after
ingestion of
the poison—longer
in the case of
modified-release preparations
or
of
drugs
with anti-
muscarinic (anticholinergic) properties. It is particularly
useful
for the prevention of absorption of poisons that
are toxic in small amounts,
such as antidepressants.
For the use of charcoal in active elimination techniques,
see below.
Active elimination techniques
Repeated
doses
of
activated
charcoal
by
mouth
enhance the elimination
of some drugs after they have
been absorbed;
repeated doses are given after
over-
dosage with:
Carbamazepine
Dapsone
Phenobarbital
Quinine
Theophylline
The usual
dose of
activated charcoal
in adults
and
children over 12 years of age is 50 g initially then 50 g
every 4 hours.
Vomiting should be treated (e.g.
with an
antiemetic drug)
since it
may reduce the efficacy of
charcoal
treatment.
In cases of
intolerance,
the dose
may be reduced and the frequency increased (e.g.
25 g
every 2 hours
or
12.5 g every hour)
but
this
may
compromise efficacy.
In children under 12 years of age,
activated charcoal is
given in a dose of 1 g/kg (max. 50 g) every 4 hours; the
dose may be reduced and the frequency increased if not
tolerated.
Other techniques intended to enhance the elimination of
poisons after absorption are only practicable in hospital
and are only suitable for a small
number of
severely
poisoned patients.
Moreover,
they only apply to a lim-
ited number of poisons.
Examples include:
.
haemodialysis for ethylene glycol,
lithium,
metha-
nol,
phenobarbital,
salicylates,
and sodium val-
proate;
.
alkalinisation of the urine for salicylates.
Removal from the gastro-intestinal
tract
Gastric lavage is rarely required;
for
substances that
cannot
be removed effectively by other
means (e.g.
iron),
it should be considered only if
a life-threatening
amount has been ingested within the previous hour.
It
should be carried out only if the airway can be protected
adequately. Gastric lavage is contra-indicated if a corro-
sive
substance
or
a
petroleum distillate
has
been
ingested,
but
it
may occasionally be considered in
patients who have ingested drugs that are not adsorbed
by charcoal, such as iron or lithium. Induction of
emesis
(e.g.
with ipecacuanha)
is not recommended because
there is no evidence that it affects absorption and it may
increase the risk of aspiration.
Whole bowel irrigation
(by means of a bowel cleansing
preparation)
has been used in poisoning with certain
modified-release
or
enteric-coated
formulations,
in
severe poisoning with iron and lithium salts, and if illicit
drugs are carried in the gastro-intestinal
tract
(‘body-
packing’).
However,
it
is not
clear that
the procedure
improves outcome and advice should be sought
from
the National Poisons Information Service.
CHARCOAL, ACTIVATED
Indications
reduction of absorption of poisons in the
gastro-intestinal system;
see also active elimination
techniques,
above
Cautions
drowsy or comatose patient (risk of aspira-
tion,
ensure airway protected); reduced gastro-intes-
tinal motility (risk of obstruction);
not for poisoning
with petroleum distillates,
corrosive substances,
alcohols, malathion, and metal salts including iron and
lithium salts
Side-effects
black stools
Dose
. Reduction of absorption,
ADULT
and
CHILD
over 12
years, 50 g;
CHILD
under 12 years, 1 g/kg (max.
50 g)
. Active elimination,
see notes above
Note
Activated charcoal doses in BNF may differ from those
in product literature.
Suspension or reconstituted powder
may be mixed with soft drinks (e.g. caffeine-free diet cola) or
fruit juices to mask the taste
Actidose-Aqua
c
Advance
(Alliance)
Oral suspension
, activated charcoal 1.04 g/5 mL, net
price 50-g pack (240 mL) = £8.69
BNF 61
Emergency treatment of poisoning
33
Emergency treatment of poisoning