Quick Chart
  • Acute poisoning is a common emergency with a multitude of clinical presentations.
  • Poisoning can be deliberate or unintentional and this population can be clinically and physiologically challenging to manage.
  • Poisoning mortality and morbidity usually result from the acute effects of the toxin on the cardiovascular, central nervous or respiratory systems.
 Clinical Presentation

Most overdoses result in an exaggeration of the therapeutic effect of a drug (e.g. antihypertensives cause hypotension in overdose), though sometimes there are additional unexpected effects. Poisoning with chemicals / plants are less predictable and may require specialist input or consulting a service like the Poisons Information Centre.

When the agent involved is not known, looking for a constellation of signs & symptoms may help to determine the class of drug and guide ongoing management. These groupings of clinical features are known as 'Toxidromes'. Some common toxidromes include:

ToxidromeAgentSigns & Symptoms
Cholinergic Toxicity
  • Organophosphates
  • Carbamate insecticides
  • Mushrooms
  • Constricted pupils
  • Sweating
  • Salivation
  • Bronchorrhea
  • Lacrimation
  • Diarrhoea
  • Bradycardia
  • Agitation
  • Muscle fasciculations
  • Seizure
Anticholinergic Toxicity
  • Atropine
  • Tricyclic antidepressants
  • Antipsychotics 
    • Quetiapine
    • Olanzapine
  • Antihistamines
  • Some sleep aids
    • Doxylamine
  • Some Parkinson’s medications 
    • Benztropine
  • Some urinary incontinence drugs
    • Oxybutynin
  • Dilated pupils (that don’t constrict with light)
  • Mild hyperthermia
  • Agitation/confusion
  • Tachycardia
  • Dry mouth
  • Flushed dry skin
  • Urinary retention
Opioid Toxicity
  • Heroine
  • Oxycodone
  • Methadone
  • Morphine 
  • Fentanyl
  • Tapentadol
  • Codeine
  • Constricted pupils
  • CNS depression / Coma
  • Respiratory depression
  • low to normal blood pressure
  • Low to normal heart rate
Serotonin Toxicity
  • Antidepressants
    • SSRI
      • e.g. Sertraline
    • SNRI
      • e.g. Venlafaxine
    • MAOI’s
      • e.g. Phenelzine
  • Tramadol
  • Stimulants
    • Methamphetamine
    • MDMA
    • Cocaine
  • Herbs / Supplements
    • St John's Wort
  • Dilated pupils
  • Agitation
  • Hyperthermia
  • Hyperreflexia
  • Clonus
  • Tremor
  • Diaphoresis
  • Increased tone (rigidity in severe cases)
Sympathomimetic toxicity
  • Illicit Stimulants 
    • Methamphetamine
    • MDMA
    • Cocaine
    • Synthetic cathinones “Bath salts”
  • Medicinal Stimulants
    • Methylphenidate
  • Dilated pupils
  • Agitation
  • Tachycardia
  • Diaphoresis
  • Tremor
  • Hypertension
  • Paranoia
  • Pressured speech
 Exclusion Criteria
Exclusion Criteria
 Risk Assessment
  • A risk assessment should be done to determine existing and ongoing threats to both the patient and the clinician.
  • Protect medical personnel particularly when there may be more than one person appearing affected on a scene or if there are concerns about an airborne / inhalational chemical or poison. Consider contacting the Clinical Support Paramedic or Duty Manager in the State Operations Centre to advise before entering; consider the requirement for Special Operations Paramedics in HAZMAT environments.
  • Where it is deemed safe to do so, collect all medication packaging and place in a green and white patient medications bag to assist with agent and potential dose calculations
  • Attempt to define:
    • Agent: What have they been exposed to? Include formulation if possible (e.g. slow release)
    • Dose: How much, and by what route?
    • Time since Ingestion: When did the poisoning occur?
    • Clinical Features: Consider the potential course of action if the agent known.
  • Toxins can affect multiple systems (e.g. cardiovascular, CNS, respiratory and skin). Frequent monitoring will ensure early recognition of patient deterioration and appropriate supportive intervention / management.
  • For patients that are non-time critical, consider consulting the Australian Poisons Information Centre (PIC) on 13 11 26 for specific advice where needed.
  • There are few specific "antidotes". Typically, these are only relevant when there is long or delayed transport. It is permissible to follow the instructions on the poison’s container, however, ensure that there is follow up with Poisons Information Centre.  If the information conflicts, then follow the Poisons Information Centre’s guidance.


Primary Care
  • Primary Survey
    • Open, clear and maintain the airway
      • Consider corrosive injury if suspected ingestion of alkalis, acids, glyphosate, or paraquat. Patients with significant laryngeal or epiglottic oedema may present with stridor or hoarse voice. More non-specific symptoms which may indirectly affect the airway include recurrent emesis, haematemesis, dysphagia or drooling.
      • Suction if required
      • Insert oropharyngeal or nasopharyngeal airway (OPA/NPA)
    • Lateral position if unresponsive (use left lateral position for pregnant women)
    • Consider Oxygen with assisted ventilation if required (be aware of inadequate tidal volume)
  • Full Vital Signs Survey, particularly GCS, BGL and Pulse Oximetry
  • Repeat vital signs every 10 minutes (5 minutes if patient appears time critical) Remove contaminated clothing.
  • Flush contaminated skin and eyes with copious amounts of water.
  • Internal Ingestion:
    • Do not induce vomiting
    • Do not try to neutralise alkalis with acids or acids with alkalis
    • Within first 10 minutes of ingestion of corrosives or acids, it is permissible to try to give 100ml of water in slow sips to dilute the substance, if patient can tolerate this. Discontinue after 10 minutes as there may be penetrating ulcers or burns.
  • Complete Secondary Survey and manage injuries as required
Intermediate Care
  • Consider administering glucose gel if indicated (i.e. patient hypoglycaemic secondary to insulin overdose)
  • Consider administering naloxone if indicated
  • Apply cardiac monitor if trained and authorised
  • Warm or cool patient as indicated (e.g. hyperthermia is a severe complication associated with MDMA/ecstacy overdoses)
  • Monitor patient persistently, recording full observations every 10 minutes (or 5 minutes if time critical)
  • Transport Priority 1 if patient time critical, pre-notifying receiving facility
Advanced Care
Critical & Extended Care
  • RSI with mechanical ventilation as indicated
  • Pacing as indicated
  • Consider use of insulin/glucose in instances of calcium channel blocker and beta-blocker toxicity
  • Consider Cyanokit as required for cyanide poisoning
  • Consider Duodote (atropine and pralidoxime autoinjector) as required for organophosphate poisoning
 Additional Information


Consulting the PIC can take time. In moderate to severe poisonings where there are competing priorities, it is recommended to prioritise addressing time-critical considerations before considering consultation with the PIC.

Key Terms & Links
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