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Emergency treatment of
poisoning
These notes provide only an overview of the treatment
of poisoning, and it is strongly recommended that either
TOXBASE or the UK National
Poisons Information
Service (see below) be consulted when there is doubt
about the degree of risk or about management.
Hospital
admission
Patients who have features of
poisoning should generally be admitted to hospital.
Patients who have taken poisons with delayed action
should also be admitted,
even if
they appear
well.
Delayed-action poisons include aspirin,
iron,
paraceta-
mol,
tricyclic
antidepressants,
and
co-phenotrope
(diphenoxylate with atropine,
Lomotil
c
);
the effects of
modified-release preparations are also delayed.
A note
of all relevant information, including what treatment has
been given,
should accompany the patient to hospital.
Further information and advice
TOXBASE,
the primary clinical
toxicology database of
the National Poisons Information Service, is available on
the internet to registered users at
www.toxbase.org (a
backup site is available at www.toxbasebackup.org if the
main site cannot be accessed).
It provides information
about routine diagnosis, treatment, and management of
patients
exposed to drugs,
household products,
and
industrial and agricultural chemicals.
Specialist information and advice on the treatment
of poisoning is available day and night from the UK
National Poisons Information Service on the fol-
lowing number:
Tel:
0844 892 0111
Advice
on
laboratory
analytical
services
can
be
obtained from TOXBASE or from the National
Poisons
Information Service.
Help with identifying capsules or tablets may be avail-
able from a regional medicines information centre (see
inside front cover) or (out of
hours) from the National
Poisons Information Service.
General care
It
is often impossible to establish with certainty the
identity of the poison and the size of the dose.
This is
not usually important because only a few poisons (such
as opioids,
paracetamol,
and iron)
have specific anti-
dotes; few patients require active removal of the poison.
In most
patients,
treatment
is directed at
managing
symptoms as they arise.
Nevertheless,
knowledge of
the type and timing of poisoning can help in anticipating
the course of events. All relevant information should be
sought from the poisoned individual and from carers or
parents.
However,
such information should be inter-
preted with care because it
may not
be complete or
entirely reliable. Sometimes symptoms arise from other
illnesses
and patients
should be assessed carefully.
Accidents may involve domestic and industrial products
(the contents of
which are not
generally known).
The
National Poisons Information Service should be con-
sulted when there is doubt
about
any aspect
of
sus-
pected poisoning.
Respiration
Respiration is often impaired in unconscious patients.
An obstructed airway requires immediate attention.
In
the absence of
trauma,
the airway should be opened
with simple measures such as chin lift or jaw thrust. An
oropharyngeal or nasopharyngeal airway may be useful
in patients
with reduced consciousness
to prevent
obstruction, provided ventilation is adequate. Intubation
and ventilation should be considered in patients whose
airway cannot
be protected or
who have respiratory
acidosis
because
of
inadequate
ventilation;
such
patients should be monitored in a critical care area.
Most
poisons that
impair consciousness also depress
respiration. Assisted ventilation (either mouth-to-mouth
or
using a bag-valve-mask device)
may be needed.
Oxygen is
not
a substitute for
adequate ventilation,
although it should be given in the highest concentration
possible in poisoning with carbon monoxide and irritant
gases.
Blood pressure
Hypotension is common in severe poisoning with cen-
tral nervous system depressants. A systolic blood pres-
sure of less than 70 mmHg may lead to irreversible brain
damage or renal
tubular necrosis.
Hypotension should
be corrected initially by tilting down the head of the bed
and administration of
either
sodium chloride intra-
venous infusion or a colloidal infusion.
Vasoconstrictor
sympathomimetics (section 2.7.2)
are rarely required
and their
use may be discussed with the National
Poisons Information Service.
Fluid depletion without
hypotension is common after
prolonged coma and after
aspirin poisoning due to
vomiting,
sweating, and hyperpnoea.
Hypertension,
often transient,
occurs
less
frequently
than hypotension in poisoning;
it
may be associated
with sympathomimetic
drugs
such as
amfetamines,
phencyclidine,
and cocaine.
Heart
Cardiac conduction defects and arrhythmias can occur
in acute poisoning,
notably with tricyclic antidepres-
sants,
some antipsychotics,
and some antihistamines.
Arrhythmias often respond to correction of underlying
hypoxia,
acidosis,
or other biochemical
abnormalities,
but
ventricular
arrhythmias that
cause serious hypo-
tension require treatment
(section 2.3.1).
If
the QT
interval is prolonged, specialist advice should be sought
because the use of some anti-arrhythmic drugs may be
inappropriate. Supraventricular arrhythmias are seldom
life-threatening and drug treatment is best withheld until
the patient reaches hospital.
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Emergency treatment of poisoning