This article provides a general approach to patients with known or suspected acute poisoning from exposure to a wide variety of potentially toxic substances, including medications, recreational drugs, and common household products. Although fewer than 1% of poisonings are fatal, acute poisoning can be a challenging medical emergency. Successful management of poisoned patients involves adapting the ABCDE approach to include toxicological considerations (including expedient recognition of various classic toxidromes), performing a toxicology-focused history and physical examination, and tailoring management based on an individualized risk assessment of each patient. The risk assessment depends on patient characteristics such as age and comorbidities, as well as characteristics of the exposure, including type, route, dosage, timing, and whether the exposure was intentional or unintentional, and typically involves consultation with a toxicologist or regional poison control center (in the United States, Poison Control is available 24/7 at 1-800-222-1222). Many patients can be managed with supportive care alone and careful monitoring. Frequent reevaluation of the patient is essential, since the pharmacokinetics of a substance are altered in situations of overdose, and the clinical presentation can be dynamic as the substance is metabolized. For most serious toxic exposures, specific treatment strategies are required that include decontamination methods to reduce absorption (e.g., activated charcoal), enhanced elimination therapies (e.g., hemodialysis), or specific antidotes (e.g., naloxone for opioid toxicity, or N-acetylcysteine for acetaminophen toxicity). The monitoring and disposition requirements and the risk of complications can be estimated through a careful toxicological risk assessment and reassessment.
- Stabilize the patient using an ABCDE approach with toxicology-specific considerations.
- Evaluate for as well as for signs and symptoms of specific poisonings.
- Specific antidotes may be required.
- Once the patient has been stabilized, perform a toxicological risk assessment.
Anticipate and prepare for changes in hemodynamic and mental status, as toxins are metabolized gradually.
Modifications to the ABCDE approach
|ABCDE approach: toxicology-specific considerations |
|Alterations and possible causes||Management|
|Breathing || |
|Circulation|| || |
|Exposure|| || |
Do not treat toxic seizures with phenytoin, which can worsen the cardiotoxic effects of certain drugs (tricyclic antidepressants, theophylline, and cocaine) and is ineffective in seizures caused by withdrawal or isoniazid. 
Recognition of classic toxidromes is essential to the evaluation of patients poisoned with an unknown substance. Note that, in practice, toxidromes may manifest more subtly than described here.
|Classic toxidromes |
|Class of drug||Vital signs||Mental status||Pupils||Other examination findings|
|Cholinergics (muscarinic)|| || |
|Cholinergics (nicotinic)|| || |
|Sympathomimetics|| || |
For patients with anticholinergic syndrome, remember: blind as a bat, mad as a hatter, red as a beet, hot as a hare, and dry as a bone!
Goal of risk assessment
- Categorize the risk presented by a toxic exposure along the following spectrum (from high to low):
- Immediate threat to life and/or cognitive function
- Potential for permanent organ damage
- Potential for developing a complication (e.g., seizures, cardiac arrhythmias) that could increase the risk level
- Uncertain risk (further monitoring is required)
- Low risk (e.g., does not meet the threshold of toxic ingestion)
- Guide interventions that help convert:
- Potentially fatal toxic exposures to nonfatal toxic exposures
- Potentially toxic exposures to nontoxic exposures
- Categorize the risk presented by a toxic exposure along the following spectrum (from high to low):
Decisions affected by risk assessment
- Decontamination: indications, risk-benefit analysis, timing, method
- Antidote use: indications, risk-benefit analysis, dosing
- Supportive care requirements: hemodynamic and metabolic support, necessary consults
- Monitoring requirements: airway, cardiac, neurological
- Disposition: discharge from ED, ward admission, ICU admission, interfacility transfer
Risk assessment in toxicology does not involve a specific scoring system but instead refers to a conceptual process based on the overall clinical evaluation.
- All patients: Perform focused toxicological history and physical examination
- Obtain a limited set of routine studies for most patients.
- Consider additional laboratory studies and imaging for specific scenarios, such as:
- Refining the diagnosis
- Identifying or evaluating complications or abnormal results of routine studies
- Guiding further management, for example:
- Determining the need for enhanced elimination or a particular antidote
- Monitor the response to treatment .
Evaluate the clinical hypothesis
- Consider whether the exam and diagnostic findings are consistent with the range of possible presentations suggested by the history.
- History obtained initially can be unreliable for various reasons, for example:
- Only secondhand information is available (i.e., the patient is unresponsive or altered).
- Patients may feel the need to conceal information about the exposure.
- Consult additional resources as needed, such as:
While some substances (e.g., those with a narrow therapeutic window) inherently have more toxic potential than others, the dose of the substance is a primary determinant of the clinical effects seen. In other words: “The dose makes the poison.”
Focused toxicological history and physical examination 
Sources of information
- Obtain as much information directly from patients as possible, reassuring them about confidentiality. (e.g., regarding the use of illicit substances)
- Seek collateral sources of information if the patient is unable or unwilling to answer questions, and/or there are inconsistencies between the history and physical examination.
- EMS providers
- Chart review or pharmacy
- Witnesses or bystanders
Key historical elements
- Drug-related: e.g., drug class, immediate vs. extended-release formulation, amount, time of ingestion 
- Patient-related: e.g., age, comorbidities, clinical status
- Attempt to quantify the toxic dose ingested per kg of weight.
- Consider the possibility of multiple co-ingested substances.
- Key physical examination elements
Clinical effects of a given substance at toxic (supratherapeutic) doses can vary dramatically from the expected side effects at therapeutic doses.
|Focused toxicological history |
Reevaluate the clinical hypothesis if physical findings and diagnostic studies are inconsistent with toxic effects that are expected from the history of the exposure.
|Focused toxicological physical examination |
|Eyes and mucous membranes|| |
|Neurological exam|| |
Reassess the patient frequently! Examination findings can be dynamic as the toxin metabolizes.
Intoxication with certain substances can cause the loss of some brainstem reflexes. Multiple society guidelines state that diagnosis of brain death can only be made in the absence of intoxication. 
- Investigations should be guided by history and examination findings.
- Clearly document the time blood was drawn, so that results can be accurately interpreted.
- General serum or urine screening panels for multiple toxins are not routinely recommended, because: 
- They do not include all toxins.
- Results often do not return in time to affect acute management.
- Both false-negative and false-positive results can occur.
- Drugs or their metabolites may be detected in urine for days after any clinical symptoms have resolved; therefore, results may not explain the current presentation. 
Abnormalities (e.g., metabolic acidosis, other metabolic derangements, elevated liver enzymes) increase the risk of complications; treat appropriately and consider extended observation, admission, and involvement of critical care as necessary.
- Liver chemistries: may be deranged in acetaminophen overdose or alcohol intoxication
- Acetaminophen level: the only specific toxin routinely screened 
- ECG 
Classic causes of high anion gap metabolic acidosis: CAT MUDPILES (Cyanide/Carbon monoxide, Aspirin/Alcoholic ketoacidosis, Toluene, Methanol/Metformin, Uremia, Diabetic ketoacidosis, Paraldehyde/Propylene glycol, Isoniazid, Lactic acidosis, Ethylene glycol, Salicylates) 
Acetaminophen levels may not be detectable if the patient presents > 18 hours after overdose. 
- ABG: to help identify acid-base disorders
- Lactate and/or ketones: to further evaluate metabolic acidosis
- CPK: for suspected
- Quantitative drug levels can be helpful to guide management for the following toxins: 
There is no indication for routine imaging in poisoned patients, but the following studies may be of use in certain situations.
- X-ray chest: Consider if there is concern for pulmonary complications (e.g., aspiration, ARDS). 
- CT head: Perform routinely for patients with altered mental status that is not clearly attributable to a specific toxic exposure. 
- CT or MRI esophagus: Consider if there is suspicion for esophageal caustic injury.
- X-ray or CT abdomen: Consider if there is concern for ingestion of select radiopaque substances, e.g.: 
To remember foreign substances with a radiopaque appearance on abdominal radiography, think of CHIPES: Chloral hydrate, Heavy metals, Iodides, Phenothiazines, Enteric-coated or sustained-release substances, and Solvents. 
Decontamination is a time-sensitive intervention to prevent further toxicity of certain subtances. It should be considered urgently as the window of opportunity for life-saving benefits is often narrow. 
- Involves the removal of any residual toxin from the patient's skin and mucus membranes to:
- Prevent further transdermal and/or inhalational exposure
- Protect healthcare providers from contamination
- Decontamination of dermal or ocular exposures should be addressed during the exposure component of the ABCDE approach.
- Healthcare providers should routinely use universal precautions as minimum protection.
- Certain toxins require more aggressive surface decontamination and specialized PPE.
- Exposures to such toxins may be the result of:
- Deliberate release
- Household, industrial, or agricultural exposure
Surface decontamination should be considered in any case of known or suspected exposure to chemical, biological, radiologic, or nuclear (CBRN) hazards.
- Suspect chemical contamination if any of the following are present: 
- Substances typically requiring surface decontamination 
Patients who have been exposed to radiation but have no radioactive materials on their person do not require surface decontamination.
Prior to decontamination
- Use the appropriate level of PPE protection according to the Occupational Health and Safety Administration/Environmental Protection Agency categories (e.g., Level A, B, or C; see “Tips & links”). 
- Activate necessary protocols (e.g., for hazardous exposures, mass casualties).
- Notify external agencies according to hospital and state requirements (e.g., fire department, health department, CDC).
Procedure: Decontaminate the patient prior to entering patient care areas 
- Carefully and completely remove all clothing.
- Double-bag clothing in sealed and labeled biohazard bags.
- Wash exposed areas with copious amounts of water (and soap, if possible) for 10–15 minutes, while sponging areas gently.
- Wash any exposed open wounds and eyes (if exposed) first.
- Continue to wash the rest of the body, working from head to toe.
- Prevent water runoff from touching eyes, nose, mouth, or any unexposed areas.
- After the initial wash of eyes and/or open wounds, use water or saline to irrigate them for another 5–10 minutes.
- In situations of deliberate release, the “rinse-wipe-rinse” approach is recommended. 
Gastrointestinal decontamination 
- This refers to the removal of a toxin from the body before it is absorbed by the GI tract
- The American Academy of Clinical Toxicology (AACT) discourages routine use of these interventions, as risks often outweigh relatively limited benefits. 
- Balance the risk and benefits for each individual patient in consultation with a specialist.
|Approach to GI decontamination methods |
|Single-dose activated charcoal|| || |
|Whole bowel irrigation|| |
|Gastric lavage|| |
The use of ipecac to induce vomiting is no longer recommended by the American Academy of Clinical Toxicology. 
Activated charcoal does not adsorb metals (e.g., iron, mercury, arsenic, lead, lithium), alcohols (e.g., ethanol, methanol, ethylene glycol), organic solvents (e.g., acetone), acids, bases, or cyanides. 
- This refers to the removal of a toxin from the body after it has been absorbed by the GI tract.
- These are only indicated for a small number of toxins with specific pharmacokinetics .
- Consult a toxicologist or poison control unit before implementing one of these methods. 
|Approach to enhanced elimination methods |
Multidose activated charcoal (MDAC)
| || |
|Extracorporeal elimination techniques|
General considerations 
Prior to administration
- There is minimal high-quality evidence to support the use of most antidotes.
- Antidotes are typically most useful for drugs that have delayed, potentially severe consequences.
Antidotes are used infrequently, and as a consequence:
- May not be immediately available 
- Are associated with ↑ risk of dosing errors
- The risks of administration:
- Depend on patient-specific risk factors 
- Can be outweighed by possible benefits if the patient is extremely sick.
- Typically increase when co-ingestions have occurred 
- Many antidotes are titrated according to specific clinical effects rather than administered as a fixed dose.
- Avoid excess dosing of antidotes.
- Stop treatment at the desired therapeutic endpoint.
- Relevant monitoring markers include: : 
- Clinical signs and symptoms (e.g., blood pressure, if administering calcium to treat a calcium channel blocker overdose)
- Time to clinical response (delayed response may suggest the need for redosing or reconsideration of the diagnosis)
- Laboratory values (e.g., prothrombin time, if administering vitamin K to treat a warfarin overdose)
Intravenous lipid emulsion therapy 
- Indications: primarily used for local anesthetic toxicity
- Recommended formulation: Intralipid® 
Aggressive supportive care is essential to the successful management of poisoned patients, irrespective of the need for other interventions (e.g., decontamination, antidotes).
- Cardiorespiratory 
- Correct electrolyte derangements (e.g., hypokalemia, hypomagnesemia, hyponatremia).
- Manage severe metabolic acidosis.
- Manage hypoglycemia.
- Encourage oral carbohydrate intake and ensure resolution of hypoglycemia.
- If the patient is unconscious: IV 50% dextrose in water
- If insulin or sulfonlyurea-related: Consider a continuous dextrose infusion (e.g., 10% dextrose in 0.9% NaCl).
- Monitor glucose and potassium levels.
- Consider prophylactic dextrose in patients with salicylate toxicity to avoid cerebral hypoglycemia.
- See “ ” for more information.
- Temperature (hyperthermia) 
|Toxins with no specific antidote|
|Poisoning type||Additional information|
Many cases of poisoning can be effectively managed with supportive care alone. 
Monitoring and disposition
Duration of observation 
- May be limited to 6 hours for intentional ingestion, if:
- Peak toxicity is expected to be reached within that time
- Overall level of toxicity is predicted to be low
- Patient remains asymptomatic
- Patient has received a psychiatric consult
- May be longer (> 24 hours) in the following situations:
- Substance-related: extended-release formulation, delayed peak effects , delayed toxicity , or active metabolites . 
- Patient-related: Symptoms do not resolve with supportive treatment or complications occur.
- May be limited to 6 hours for intentional ingestion, if:
- Consider serial ECGs and continuous cardiac monitoring if:
- For patients with rhythm disturbances, monitor the following: 
- Consider the need for serial drug levels: for drugs with unpredictable absorption kinetics (e.g., salicylates, valproic acid) 
- Monitor for complications, including: 
- Don appropriate PPE.
- Perform an ABCDE approach with toxicology-specific considerations.
- Identify classic toxidromes or signs of specific poisoning.
- Consider the need for surface decontamination or time-sensitive GI decontamination.
- Administer antidotes for immediate threats to life e.g., naloxone, atropine, dextrose.
- Identify and treat life-threatening complications: e.g., cardiac arrhythmias, seizures.
- Consult critical care as needed.
- Provide aggressive supportive care:
- Perform toxicological risk assessment.
- Obtain focused toxicological history and physical examination.
- Obtain collateral history as needed (e.g., EMS, family, medical records)
- Quantify amount, time, and route of toxic exposure(s).
- Determine suicidal risk of patients with intentional exposure.
- Obtain routine studies (BMP, liver chemistry, acetaminophen level, ECG).
- Consult a toxicologist or poison center for input as needed.
Management to consider based on toxicological risk assessment
- GI decontamination: e.g., activated charcoal
- Enhanced elimination techniques: e.g., hemodialysis
- Antidotes: e.g., N-Acetylcysteine
- Additional laboratory studies and imaging
- Consults: e.g., psychiatry, nephrology, neurology.
- Serial ECGs and continuous cardiac monitoring: e.g., for patients with rhythm disturbances, cardiotoxic substances, multiple substances, unknown substances
- Monitor serial drug levels if relevant to the substance ingested.
- Determine the duration of observation according to patient risk.
- Consider admission for:
- Symptomatic patients.
- Asymptomatic patients expected to experience delayed toxicity
- Consider ICU admission for patients with:
- Need for advanced airway management OR high risk of airway compromise
- Need for mechanical ventilation OR high risk of respiratory failure
- Need for vasoactive medications OR high risk of hemodynamic instability
- High risk of life-threatening complications: e.g., cardiac arrhythmias, seizures, cerebral edema, multiorgan failure
- Need for hemodialysis
- Consider reassurance and discharge with instructions for patients with unintentional nontoxic exposures