Emergency Medicine

Tox i c o l o g y 17 9

SPECIFIC POISONS

MANAGEMENT

1 Treatment depends on haemodynamic stability, conscious state, and
whether it is an acute or chronic intoxication.

2 Gain i.v. access in all patients and start f luid resuscitation for hypotension,
continuous cardiac monitoring, and perform regular ECGs.

3 Acute digoxin intoxication
(i) Administer oral activated charcoal if presentation is within 1 h
of significant overdose. This may be impossible if the patient
is vomiting continuously. Repeated administration should not
delay other interventions.
(ii) Treat hyperkalaemia with a dextrose–insulin infusion (see p. 132)
(a) do not use i.v. calcium as this may precipitate asystole.
(iii) Administer digoxin-specific antibody fragments (Digibind™) for:
(a) cardiac arrest
(b) haemodynamic instability with cardiac arrhythmia
(c) serum potassium >5.5 mmol/L
(d) serum digoxin level >15 nmol/L (11.7 ng/mL)
(e) ingested digoxin dose >10 mg (4 mg in a child).
(iv) Calculate the number of vials of Digibind™ required from the
estimated ingested dose or the serum digoxin concentration, if
obtained at least 6 h post acute poisoning
(a) Empiric dosing starting with 5–10 vials of Digibind™ will be
required if the acutely ingested dose is unknown.
(v) Admit all acute poisonings for cardiac monitoring and close
observation for a minimum of 12 h.

4 Chronic digoxin intoxication
(i) Cease the digoxin medication.
(ii) Correct any hypokalaemia with potassium chloride 10 mmol/h
i.v., and hypomagnesaemia with magnesium sulphate 10 mmol in
100 mL normal saline i.v. over 30 min.
(iii) Administer two vials of digoxin-specific antibody fragments
(Digibind™) i.v. over 30 min to symptomatic patients with an altered
mental state, cardiac arrhythmia or gastrointestinal symptoms.
(iv) Patients usually recover quickly. Admit under the medical
team for treatment of any ongoing cardiac instability, renal
impairment and electrolyte disturbances.

Lithium

DIAGNOSIS

1 Lithium toxicity may be acute or chronic. Toxicity is associated with
significant morbidity and mortality, and an acute overdose of >250 mg/kg
(25 g).