What are the key steps in the initial assessment and management of a patient presenting with suspected poisoning?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 17 August 2025Updated: 17 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

The key steps in the initial assessment and management of a patient presenting with suspected poisoning involve immediate life-saving measures, rapid assessment for emergency transfer, detailed history taking, physical examination, and appropriate referral or management based on the substance and patient's condition .

  • Immediate Assessment and Resuscitation (ABCDE Approach)
    • If the person has collapsed and is unresponsive, ensure the airway is open (in the absence of trauma) and check for normal breathing .
    • If they are not breathing normally, start cardiopulmonary resuscitation (CPR) immediately and call for an ambulance .
    • Assess the person's overall status using the ABCDE approach .
    • Perform a rapid assessment of the airway, removing any obstructions, assessing for injury (e.g., from corrosive substances), and securing a patent airway .
    • Assess the person's consciousness, commonly using the Glasgow Coma Scale .
    • Measure respiratory rate and, if available, oxygen saturations using a pulse oximeter .
    • Measure the person's pulse, blood pressure, and temperature .
  • Criteria for Emergency Transfer to Hospital
    • Arrange emergency transfer to hospital if the person is unconscious or has a reduced level of consciousness .
    • Transfer is also required if there is a reduced respiratory rate or oxygen saturation, hypotension, tachycardia, bradycardia, an irregular pulse, hypothermia, hyperthermia, or a seizure .
    • Any other concerning clinical features or a deteriorating condition also warrant emergency transfer .
    • Refer all people who have taken or been exposed to an unknown drug urgently to hospital .
    • Consider admitting children, pregnant women, people with pre-existing comorbidities, or those taking concomitant medication, even if the drug is considered to have a good safety profile .
  • Assessment if Emergency Transfer is Not Required
    • History Taking: Ask about the substance taken (amount, other medicines, alcohol use), when it was taken (exact timing is crucial for paracetamol poisoning), the route of administration (mouth, inhalation, injection), and why it was taken (accidental, deliberate, therapeutic error) . Inquire about the risk of repetition . Gather other relevant details such as age, weight, sex, medical history (including psychiatric history and self-harm), current medication, and factors affecting poison excretion or metabolism (e.g., renal or hepatic impairment) . Ask about any symptoms the person is experiencing .
    • Physical Examination: Perform an examination depending on the clinical situation . This may include general observations (e.g., track marks, alcohol on breath, atypical bruising, skin blisters) . Conduct a neurological examination, including pupil size and reaction, and eye movements . Check for signs consistent with the suspected poison or compare findings to common toxidromes if the poison is unknown .
    • Psychosocial Assessment (for deliberate self-poisoning): If the person has deliberately self-poisoned, conduct a preliminary psychosocial assessment to determine mental capacity, willingness for further assessment, level of distress, and possible mental illness . People who have self-harmed will require a further psychosocial assessment by a trained specialist after their physical problems are treated . Assess the likely physical risk, emotional and mental state, and risk of further self-harm or suicide, identifying features like depression, hopelessness, and continuing suicidal intent . This assessment should be carried out concurrently with physical healthcare as soon as possible . Communicate assessment outcomes to other involved healthcare professionals .
    • Safeguarding Concerns: Assess any safeguarding concerns for people of all ages, including adults, older people, children, and young people . Consider child neglect if there are repeated presentations of accidental ingestion of poisons in a child . Suspect child maltreatment in cases of poisoning in children if there is a report of deliberate administration of inappropriate substances, unexpected blood levels of unprescribed drugs, biochemical evidence of toxic substance ingestion, the child could not access the substance independently, the explanation is absent or unsuitable, or there are repeated ingestions in the child or other household children .
  • Management and Information Sources
    • Consult the poisons information database, TOXBASE, for information on specific poisons and to guide management .
    • Telephone the National Poisons Information Service (NPIS) for advice if poisoning is severe or complex, the person has significant comorbidity, there are uncertainties after consulting TOXBASE, or the poison is unknown .
    • Telephone the UK Teratology Information Service (UKTIS) for advice if the person is pregnant .
    • Investigations are not routinely necessary or appropriate in primary care for those who do not need emergency hospital referral .
    • For accidental poisoning with substances considered of low toxicity, hospital assessment is usually not indicated . Advise the person they may experience mild gastrointestinal upset and to drink a small glass of water, milk, or juice if this occurs . Advise them when to seek medical advice (e.g., if symptoms worsen or new symptoms develop) . If a considerable quantity of a low toxicity substance was ingested, or if symptoms other than mild gastrointestinal upset occur, follow advice from TOXBASE .

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