Emergency Medicine

176 Tox icolog y

SPECIFIC POISONS

2 Administer norma l sa line to maintain a norma l blood pressure (BP).

3 Gastrointestinal decontamination is rarely necessary unless there is

co-ingestion or the patient is deeply unconscious, in which case protect the

air way f irst by endotrachea l intubation.

4 Admit the patient to the ED observation unit overnight, followed by sub-

sequent psychiatric evaluation.

5 The use of f lumazenil, a specific benzodiazepine receptor antagonist, is

controversial. It is rarely if ever indicated, and must be discussed with the

senior ED doctor.

(i) Flumazenil may induce VT, elevate intracranial pressure,

precipitate benzodiazepine withdrawal in chronic abusers, and

may invoke seizures, particularly with co-ingestion of TCAs.

(ii) Potential roles for flumazenil are thus restricted to:

(a) reversal of excessive benzodiazepine sedative effect following

procedural sedation

(b) reversal of respiratory depression and coma in a pure

benzodiazepine overdose, to prevent the need for intubation.

The difficulty is knowing when no other drugs were ingested.

Opioids

DIAGNOSIS

1 Opioid drugs include opium alkaloids such as morphine and codeine; semi-

synthetic opioids such as heroin (diamorphine) and oxycodone and fully

synthetic opioids such as pethidine and methadone.

2 Opioids produce euphoria, pinpoint pupils, sedation, respiratory depression

and apnoea with increasing doses.

3 Other complications of opioid intoxication include hypotension, convul-

sions, non-cardiogenic pulmonary oedema and compartment syndrome

from prolonged immobility.

4 Perform a thorough examination to evaluate potential complications, and to

exclude alternative causes of an altered mental state with bradypnoea such as

sepsis, neurotrauma, stroke and metabolic disease (see p. 80).

5 Send bloods for U&Es, blood sugar and serum paracetamol level. Perform an

ECG.

MANAGEMENT

1 Commence supportive care wit h ox ygen and assisted ventilation.

2 Give naloxone 0.1–0.4 mg i.v. as a bolus or in 0.1 mg increments. Carefully

titrate response to achieve improved airway control and adequate ventila-

tion, without precipitating an acute agitated withdrawal state.