Poisoning is contact with a substance that results in toxicity. Symptoms vary, but certain common syndromes suggest exposure to particular classes of poisons. Poisoning is usually a clinical diagnosis but laboratory testing is available and clinically useful for certain poisons. Treatment is supportive for most cases of poisoning; specific antidotes are administered for certain substances. Prevention includes labeling medication containers clearly and keeping poisons out of the reach of children.
Poisoning is commonly due to ingestion but can result from injection, inhalation, or exposure of body surfaces (eg, skin, eye, mucous membranes). The toxicity of poisoning with most substances is dose-related. Dose is determined by concentration over time. Toxicity may result from exposure to excess amounts of normally nontoxic substances or to substances that are poisonous at all doses. Poisoning is distinguished from hypersensitivity (immune-mediated reaction) and idiosyncratic reactions (unexpected reaction in an individual person), which are unpredictable and not dose-related, and from intolerance (non-immune mediated reaction to a dose of a substance that is usually a nontoxic dose), which are predictable and dose-dependent. Intolerance reactions are generally less severe than hypersensitivity or idiosyncratic reactions.
People are often concerned and seek medical advice when exposed to a nonfood substance through ingestion or other routes (eg, inhalation of chemical fumes). Many commonly used products are nontoxic, but some exposures can cause severe, even life-threatening, toxicity depending on the substance, route of exposure, dose, and patient characteristics. Patients should be advised to call their local poison center for advice about a potential poisoning and/or to seek emergency care. In the United States, information about poisons is available through America's Poison Centers (1-800-222-1222) and PoisonHelp.org.
Accidental poisoning is common among young children, who are curious and ingest items indiscriminately despite noxious tastes and odors; usually, only a single substance is involved, but ingestion of multiple substances should be considered. Accidental poisoning may occur in older adults because of confusion, poor eyesight, mental health conditions, or polypharmacy (simultaneous use of multiple medications, often prescribed by multiple clinicians) (see also Medication-Related Problems in Older Adults).
Intentional poisoning to attempt suicide is common among older children, adolescents, and adults; multiple illicit drugs and medications, including alcohol, benzodiazepines, and acetaminophenacetaminophen and other over-the-counter (OTC) medications may be involved.
Occasionally, people are poisoned by someone who intends to harm them (eg, during a robbery or sexual assault). Drugs used to impair people (eg, scopolaminescopolamine, benzodiazepines, gamma-hydroxybutyrate) tend to have sedative or amnestic properties or both. Rarely, parents poison their children because of unclear psychiatric reasons or a desire to cause illness and thus gain medical attention (a disorder called factitious disorder imposed on another [formerly called Munchausen syndrome by proxy]).
After exposure, poisons may pass through the gastrointestinal (GI) tract or be absorbed directly into tissues or the circulation. They may be metabolized or excreted. Occasionally, tablets (eg, aspirin, iron, enteric-coated medications) form large concretions (After exposure, poisons may pass through the gastrointestinal (GI) tract or be absorbed directly into tissues or the circulation. They may be metabolized or excreted. Occasionally, tablets (eg, aspirin, iron, enteric-coated medications) form large concretions (bezoars) in the GI tract, where they tend to remain, continuing to be absorbed and cause toxicity.
Symptoms and Signs of Poisoning
Symptoms and signs of poisoning vary depending on the substance (see table Symptoms and Treatment of Specific Poisons). Also, different patients poisoned with the same substance may present with very different symptoms (1). However, 6 clusters of symptoms (toxic syndromes, or toxidromes) occur commonly and may suggest toxicity caused by particular classes of substances (see table Common Toxic Syndromes). Patients who ingest multiple substances may have symptoms characteristic of a single substance, but often have a combination of symptoms that are difficult to attribute to a single substance.
Common Toxic Syndromes
Syndrome | Symptoms | Common Causes |
|---|---|---|
Anticholinergic | Tachycardia, hyperthermia, mydriasis, warm and dry skin, urinary retention, ileus, delirium (a mnemonic in English for this combination of symptoms is “mad as a hatter, blind as a bat, red as a beet, hot as a hare, and dry as a bone”*) | Antihistamines AtropineAtropine Belladonna alkaloids Datura (angel's trumpet) Jimson weed Psychoactive drugs (many) ScopolamineScopolamine Tricyclic antidepressants |
Cholinergic, muscarinic | Salivation, Lacrimation, Urination, Defecation, GI cramps, Emesis (mnemonic in English: SLUDGE) or Diarrhea; Urination; Miosis; Bronchorrhea, Bradycardia, and Bronchoconstriction; Emesis; Lacrimation; and Salivation (mnemonic in English: DUMBELS) Wheezing | Carbamates Organophosphates†, ‡ PhysostigminePhysostigmine PilocarpinePilocarpine PyridostigminePyridostigmine |
Cholinergic, nicotinic | Mydriasis, Tachycardia, Weakness, Hypertension and Hyperglycemia, Fasciculations, Sweating (mnemonic in English is an acronym with the same letters as the days of the week: MTWT[h]FS) Abdominal pain, paresis | Black widow spider bites Carbamates NicotineNicotine Organophosphates (some)†, ‡ |
Opioid§ | Hypoventilation, hypotension, miosis, sedation, possibly hypothermia | Opioids (eg, buprenorphine, diphenoxylate, fentanyl, carfentanyl, norfentanyl, remifentanil, heroin, methadone, morphine, pentazocine, propoxyphene, oxycodone, hydromorphone)Opioids (eg, buprenorphine, diphenoxylate, fentanyl, carfentanyl, norfentanyl, remifentanil, heroin, methadone, morphine, pentazocine, propoxyphene, oxycodone, hydromorphone) |
Sympathomimetic║ | Tachycardia, hypertension, mydriasis, agitation, seizures, diaphoresis, hyperthermia, psychosis (after chronic use) | CaffeineCaffeine EphedrineEphedrine Herbal and synthetic marijuana and common substitutes Phenylpropanolamine Substituted cathinones ("bath salts") TheophyllineTheophylline |
Withdrawal (various drug classes)a | Tachycardia, mild hypertension, mydriasis, diaphoresis, agitation, restlessness, anxiety, hyperreflexia, piloerection, yawning, abdominal cramps, lacrimation, flu-like symptoms, insomnia, vomiting and diarrhea | Withdrawal from the following sedating or recreational drugs: |
Agitation, hallucinations, confusion, disorientation, seizures, hyperreflexia, hypertension, tachycardia, arrhythmias, dehydration, autonomic instability, death, severe muscle spasm (baclofen)Agitation, hallucinations, confusion, disorientation, seizures, hyperreflexia, hypertension, tachycardia, arrhythmias, dehydration, autonomic instability, death, severe muscle spasm (baclofen) | Withdrawal from the following drugs with sedative-hypnotic effects:
| |
Decreased mental alertness, lethargy, coma, decreased blood pressure, decreased heart rate | Withdrawal from the following drugs with sympathomimetic effects: | |
Mild flu-like symptoms, insomnia, restlessness and anxiety | Withdrawal from the following medications with antidepressant effects: | |
* From Carroll L: Alice's Adventures in Wonderland. London, MacMillan & Co., 1865. † Tuovinen K. Organophosphate-induced convulsions and prevention of neuropathological damages. Toxicology. 2004;196(1-2):31-39. doi:10.1016/j.tox.2003.10.013 ‡ Eddleston M, Buckley NA, Eyer P, Dawson AH. Management of acute organophosphorus pesticide poisoning. Lancet. 2008;371(9612):597-607. doi:10.1016/S0140-6736(07)61202-1 §Sharma B, Bruner A, Barnett G, Fishman M. Opioid Use Disorders. Child Adolesc Psychiatr Clin N Am. 2016;25(3):473-487. doi:10.1016/j.chc.2016.03.002 ║Brown H, Pollard KA. Drugs of Abuse: Sympathomimetics. Crit Care Clin. 2021;37(3):487-499. doi:10.1016/j.ccc.2021.03.002 aGortney JS, Raub JN, Patel P, et al. Alcohol withdrawal syndrome in medical patients. Cleve Clin J Med. 2016;83(1):67-79. doi:10.3949/ccjm.83a.14061 bFava GA, Cosci F. Understanding and Managing Withdrawal Syndromes After Discontinuation of Antidepressant Drugs. J Clin Psychiatry. 2019;80(6):19com12794. Published 2019 Nov 26. doi:10.4088/JCP.19com12794 | ||
GHB = gamma-hydroxybutyrate; MDMA = methylenedioxymethamphetamine; MAOI = monoamine oxidase inhibitor; PCP = phencyclidine; SSRI = selective serotonin reuptake inhibitor. | ||
Symptoms typically begin soon after exposure but, with certain poisons, are delayed. The delay may occur because only a metabolite is toxic rather than the parent substance (eg, methanol, ethylene glycol, hepatotoxins). Ingestion of hepatotoxins (eg, acetaminophenacetaminophen, iron, Amanita phalloides mushrooms) may cause acute liver failure that occurs one to a few days later. With metals or hydrocarbon solvents, symptoms typically occur only after chronic exposure to the toxin.
Ingested and absorbed toxins generally cause systemic symptoms. Caustics and corrosive liquids damage mainly the mucous membranes of the gastrointestinal (GI) tract, causing stomatitis, enteritis, or perforation. Some toxins (eg, alcohol, hydrocarbons) cause characteristic breath odors. Skin contact with toxins can cause various acute cutaneous symptoms (eg, rashes, pain, blistering); chronic exposure may cause dermatitis.
Inhaled toxins are likely to cause symptoms of upper airway injury if they are water-soluble (eg, chlorine, ammonia) and symptoms of lower airway injury and noncardiogenic pulmonary edema if they are less water-soluble (eg, phosgene). Inhalation of carbon monoxide, cyanide, or hydrogen sulfide gas can cause organ ischemia or cardiac or respiratory arrest. Eye contact with toxins (solid, liquid, or vapor) may damage the cornea, sclera, and lens, causing eye pain, redness, and loss of vision.
Some substances (eg, cocainecocaine, phencyclidine, amphetamineamphetamine) can cause severe agitation, which can result in hyperthermia, acidosis, and rhabdomyolysis.
Symptoms and Signs Reference
1. Holstege CP, Borek HA. Toxidromes. Crit Care Clin. 2012;28(4):479-498. doi:10.1016/j.ccc.2012.07.008
Diagnosis of Poisoning
Primarily history and physical examination, including history from all available sources (patient and others who might have observed the patient's exposure to a toxin)
Sometimes directed laboratory testing for specific substances
The first step of diagnosis of poisoning is to assess the overall status of the patient. Severe poisoning may require rapid intervention to treat airway compromise or cardiopulmonary collapse.
At clinical presentation, it may be known that poisoning has occurred. It should be suspected if patients have unexplained symptoms, especially altered consciousness (which can range from agitation to somnolence to coma). If purposeful self-poisoning occurs in adults, multiple substances should be suspected.
History is often the most valuable diagnostic tool. Pharmacy and medical records may provide useful information. It is important to gather as much information as possible about the exposure to attempt to identify the substance (or sometimes multiple substances), route of exposure (eg, ingestion, inhalation), amount, and time of exposure. Because many patients (eg, preverbal children, adults with suicidal ideation or experiencing psychosis, patients with altered consciousness) cannot provide reliable information, friends, relatives, and rescue personnel should be questioned. Even seemingly reliable patients may incorrectly report the amount or time of ingestion. Sometimes, people who were at the location where the exposure occurred can provide information about clues that helps guide care of the patient (eg, partially empty pill containers, a suicide note, evidence of recreational drug use). In potential workplace poisonings, coworkers and supervisors should be questioned. All industrial chemicals must have a material safety data sheet (MSDS) readily available at the workplace; the MSDS provides detailed information about toxicity and any specific treatment.
In many parts of the world, information about household and industrial chemicals can be obtained from poison control centers. Consultation with the centers is encouraged because ingredients, first-aid measures, and antidotes printed on product containers are occasionally inaccurate or outdated. Also, the container may have been replaced, or the package may have been tampered with. Poison control centers may be able to help identify unknown pills based on their appearance. The centers have ready access to toxicologists. The telephone number of the nearest center is often listed with other emergency numbers in the front of the local telephone book; the number is also available from the telephone operator or, in the United States, by dialing 1-800-222-1222. More information is available at America's Poison Centers.
Physical examination sometimes detects signs suggesting particular types of substances (eg, toxidromes [see table Common Toxic Syndromes], breath odor, presence of topical drugs or medications, needle marks or tracks suggesting injected drug use, stigmata of chronic alcohol use).
Even if a patient is known to be poisoned, altered consciousness due to other causes (eg, central nervous system infection, head trauma, hypoglycemia, stroke, hepatic encephalopathy, Wernicke encephalopathy) should also be considered. Attempted suicide must always be considered in older children, adolescents, and adults who have ingested a drug or medication (see Suicidal Behavior and Suicidal Behavior in Children and Adolescents). Also, children and adolescents often share found pills and substances; careful inquiry to identify additional potentially poisoned patients among playmates and siblings should be undertaken.
Laboratory testing
In most cases, laboratory testing for specific substances is limited. Standard, readily available urine or blood tests to identify common drugs of abuse (often called toxic screens) are qualitative, not quantitative. These tests may provide false-positive or false-negative results, and they check for only a limited number of substances. Urine drug screening testing is used most often but has limited value and usually detects classes of drugs or medications or metabolites rather than specific substances. For example, an opioid urine immunoassay test does not detect fentanyl or methadone but does react with very small amounts of morphine or codeine analogues. The test used to identify cocaine detects a metabolite rather than cocaine itself. Also, the presence of a drug of abuse does not necessarily indicate that the drug caused the patient’s symptoms or signs (ie, a patient who had recently taken an opioid may in fact be obtunded because of encephalitis rather than the drug). In most cases, laboratory testing for specific substances is limited. Standard, readily available urine or blood tests to identify common drugs of abuse (often called toxic screens) are qualitative, not quantitative. These tests may provide false-positive or false-negative results, and they check for only a limited number of substances. Urine drug screening testing is used most often but has limited value and usually detects classes of drugs or medications or metabolites rather than specific substances. For example, an opioid urine immunoassay test does not detect fentanyl or methadone but does react with very small amounts of morphine or codeine analogues. The test used to identify cocaine detects a metabolite rather than cocaine itself. Also, the presence of a drug of abuse does not necessarily indicate that the drug caused the patient’s symptoms or signs (ie, a patient who had recently taken an opioid may in fact be obtunded because of encephalitis rather than the drug).
Pearls & Pitfalls
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For most substances, blood levels cannot be easily determined or do not help guide treatment. For a few substances (eg, acetaminophen, aspirin, carbon monoxide, digoxin, ethylene glycol, iron, lithium, methanol, phenobarbital, phenytoin, theophylline), blood levels may help guide treatment. Many authorities recommend measuring acetaminophen levels in all patients with mixed ingestions because acetaminophen ingestion is common, is often asymptomatic during the early stages, and can cause serious delayed toxicity that can be prevented by an antidote. For some substances, other blood tests (eg, PT [prothrombin time] for warfarin overdose, methemoglobin levels for certain substances) help guide treatment.
If blood levels of a substance or symptoms of toxicity increase after initially decreasing or persist for an unusually long time, a bezoar, a sustained-release preparation, or reexposure (ie, repeated covert exposure to a recreationally used drug) should be suspected.
For patients who have altered consciousness or abnormal vital signs or who have ingested certain substances, laboratory tests may include serum electrolytes, blood urea nitrogen (BUN), creatinine, glucose, coagulation studies, and venous blood gases (VBGs). Other tests (eg, serum osmolality, methemoglobin level, carbon monoxide level, brain CT) may be indicated for certain suspected poisons or in certain clinical situations.For patients who have altered consciousness or abnormal vital signs or who have ingested certain substances, laboratory tests may include serum electrolytes, blood urea nitrogen (BUN), creatinine, glucose, coagulation studies, and venous blood gases (VBGs). Other tests (eg, serum osmolality, methemoglobin level, carbon monoxide level, brain CT) may be indicated for certain suspected poisons or in certain clinical situations.
For certain poisonings (eg, due to iron, lead, arsenic, other metals, or to packets of cocaine or other illicit drugs ingested or inserted into body cavities for the purpose of smuggling the drugs or hiding them from law enforcement officers [a practice called body packing]), radiographic studies such as plain x-ray or CT scan plain abdominal radiographs may show the presence and location of ingested substances.For certain poisonings (eg, due to iron, lead, arsenic, other metals, or to packets of cocaine or other illicit drugs ingested or inserted into body cavities for the purpose of smuggling the drugs or hiding them from law enforcement officers [a practice called body packing]), radiographic studies such as plain x-ray or CT scan plain abdominal radiographs may show the presence and location of ingested substances.
For poisonings with drugs or medications that have cardiovascular effects or with an unknown substance, electrocardiography (ECG) and cardiac monitoring are indicated.
Treatment of Poisoning
Supportive care
Prevent absorption (eg, activated charcoal for oral poisonings)Prevent absorption (eg, activated charcoal for oral poisonings)
Enhance excretion (eg, dialysis)
Mitigate toxicity (eg, manage cardiovascular effects)
Sometimes, specific antidotes
Patients with severe poisoning may require assisted ventilation or treatment of cardiovascular collapse. Patients with impaired consciousness may require continuous monitoring or restraints. The discussion of treatment for specific poisonings, below and in tables Common Specific Antidotes, Guidelines for Chelation Therapy, and Symptoms and Treatment of Specific Poisons, is general and does not include specific complexities and details. Consultation with a poison control center is recommended for any poisonings except the mildest and most routine.
Initial stabilization
Maintain airway, breathing, and circulation
IV naloxoneIV naloxone
IV dextrose and thiamineIV dextrose and thiamine
IV fluids, sometimes vasopressors
Airway, breathing, and circulation must be maintained in patients suspected of a systemic poisoning. Patients without a pulse or blood pressure require emergency cardiopulmonary resuscitation.
If patients have apnea or compromised airways (eg, foreign material in the oropharynx, decreased gag reflex), they should receive assisted ventilation and a dose of IV naloxone. If the patient does not have a rapid response to the naloxone, an endotracheal tube should be inserted (see If patients have apnea or compromised airways (eg, foreign material in the oropharynx, decreased gag reflex), they should receive assisted ventilation and a dose of IV naloxone. If the patient does not have a rapid response to the naloxone, an endotracheal tube should be inserted (seeTracheal Intubation). If patients have respiratory depression or hypoxia, supplemental oxygen or mechanical ventilation should be provided as needed.
IV naloxoneIV naloxone (adults, adolescents, and children ≥ 5 years or > 20 kg: 0.4 to 2 mg every 2 to 3 minutes as needed up to a maximum total dose of 10 mg; Infants and children < 5 years or ≤ 20 kg: 0.1 mg/kg in children, may be repeated every 2 to 3 minutes until desired response is achieved) should be given immediately while maintaining airway support in patients with apnea or severe respiratory depression. In patients with opioid addiction, naloxone may precipitate withdrawal, but withdrawal is preferable to severe respiratory depression. If respiratory depression persists despite use of naloxone, endotracheal intubation and continuous mechanical ventilation are required. If naloxone relieves respiratory depression, patients are monitored; if respiratory depression recurs, patients should be treated with another bolus of IV naloxone or endotracheal intubation and mechanical ventilation. Using a low-dose continuous relieves respiratory depression, patients are monitored; if respiratory depression recurs, patients should be treated with another bolus of IV naloxone or endotracheal intubation and mechanical ventilation. Using a low-dose continuousnaloxone infusion to maintain respiratory drive without precipitating withdrawal has been suggested but in reality can be very difficult to accomplish.
IV dextroseIV dextrose (50 mL of a 50% solution for adults, 5 to 10mL/kg of a 10% solution in infants and children, 2 to 4 mL/kg of a 25% solution for older children) should be given to patients with altered consciousness or central nervous system depression, unless hypoglycemia has been ruled out by immediate bedside determination of blood glucose.
ThiamineThiamine (100 mg IV) is given with or before glucose to adults with suspected thiamine deficiency (eg, patients with alcohol use disorder, patients who are undernourished).(100 mg IV) is given with or before glucose to adults with suspected thiamine deficiency (eg, patients with alcohol use disorder, patients who are undernourished).
IV fluids are given for hypotension. If fluids are ineffective, invasive hemodynamic monitoring may be necessary to guide fluid and vasopressor therapy. The first-choice vasopressor for most poison-induced hypotension is norepinephrine 0.5 to 1 mg/min IV infusion, but treatment should not be delayed if another vasopressor is more immediately available.are given for hypotension. If fluids are ineffective, invasive hemodynamic monitoring may be necessary to guide fluid and vasopressor therapy. The first-choice vasopressor for most poison-induced hypotension is norepinephrine 0.5 to 1 mg/min IV infusion, but treatment should not be delayed if another vasopressor is more immediately available.
Topical decontamination
Any body surface (including the eyes) exposed to a toxin is flushed with large amounts of water or saline. Contaminated clothing, including shoes, socks, and jewelry should be removed. Topical patches and transdermal delivery systems are removed.
Activated charcoal
Oral activated charcoal may be given, particularly when patients present within 1 to 2 hours of ingestion that can cause toxicity. Use of charcoal adds little risk (except in patients at risk of vomiting and aspiration) but has not been proved to reduce overall morbidity or mortality. When used, charcoal is given as soon as possible. Activated charcoal adsorbs most toxins because of its molecular configuration and large surface area. Multiple doses of activated charcoal may be effective for substances that undergo enterohepatic recirculation (eg, Oral activated charcoal may be given, particularly when patients present within 1 to 2 hours of ingestion that can cause toxicity. Use of charcoal adds little risk (except in patients at risk of vomiting and aspiration) but has not been proved to reduce overall morbidity or mortality. When used, charcoal is given as soon as possible. Activated charcoal adsorbs most toxins because of its molecular configuration and large surface area. Multiple doses of activated charcoal may be effective for substances that undergo enterohepatic recirculation (eg,phenobarbital, theophylline) and for sustained-release preparations. Charcoal may be given at 4- to 6-hour intervals for serious poisoning with such substances unless bowel sounds are hypoactive. Charcoal is ineffective for caustics, alcohols, and simple ions (eg, cyanide, iron, other metals, ) and for sustained-release preparations. Charcoal may be given at 4- to 6-hour intervals for serious poisoning with such substances unless bowel sounds are hypoactive. Charcoal is ineffective for caustics, alcohols, and simple ions (eg, cyanide, iron, other metals,lithium).
The recommended dose is 5 to 10 times the volume of the suspected toxin ingested. However, because the amount of toxin ingested is usually unknown, the usual dose is 0.5 to 2 g/kg, which is approximately 10 to 25 g for children < 5 years and 50 to 100 g for older children and adults. Charcoal is given as a slurry in water or soft drinks. It may be unpalatable and results in vomiting in approximately 30% of patients (5 years and 50 to 100 g for older children and adults. Charcoal is given as a slurry in water or soft drinks. It may be unpalatable and results in vomiting in approximately 30% of patients (1). Administration via a gastric tube may be considered, but caution should be used to prevent trauma caused by tube insertion or aspiration of charcoal; potential benefits must outweigh risks. Activated charcoal should probably be used without sorbitol or other cathartics, which have no clear benefit and can cause dehydration and electrolyte abnormalities (). Administration via a gastric tube may be considered, but caution should be used to prevent trauma caused by tube insertion or aspiration of charcoal; potential benefits must outweigh risks. Activated charcoal should probably be used without sorbitol or other cathartics, which have no clear benefit and can cause dehydration and electrolyte abnormalities (2).
After administration, activated charcoal will eventually pass in the stool, and patients should be informed that they may have constipation and/or black stools. After administration, activated charcoal will eventually pass in the stool, and patients should be informed that they may have constipation and/or black stools.
Gastric emptying
Gastric emptying, either with syrup of ipecac or gastric lavage, has not been shown to be effective and now is only rarely performed and then only in ingestions that present early, are potentially lethal, and have no other effective treatments (3). It does not clearly reduce overall morbidity or mortality and, in some cases (eg, caustic substance ingestion), is contraindicated (see Caustic Ingestion).
Whole-bowel irrigation
This procedure flushes the GI tract and theoretically decreases GI transit time for pills and tablets. Irrigation has not been proved to reduce morbidity or mortality. Irrigation is indicated for any of the following (4):
Some serious poisonings due to sustained-release preparations or substances that are not adsorbed by charcoal (eg, heavy metals)Some serious poisonings due to sustained-release preparations or substances that are not adsorbed by charcoal (eg, heavy metals)
Drug packets (eg, latex-coated packets of heroin or cocaine ingested or inserted into body cavities for the purpose of smuggling the drugs or hiding them from law enforcement officers [a practice called body packing])Drug packets (eg, latex-coated packets of heroin or cocaine ingested or inserted into body cavities for the purpose of smuggling the drugs or hiding them from law enforcement officers [a practice called body packing])
A suspected bezoar
A commercially prepared solution of polyethylene glycol (which is nonabsorbable) and electrolytes may be given, with dose varying by age and/or weight, until the rectal effluent is clear (A commercially prepared solution of polyethylene glycol (which is nonabsorbable) and electrolytes may be given, with dose varying by age and/or weight, until the rectal effluent is clear (4); this process may require many hours or even days. The solution is usually given via a gastric tube, although some motivated patients can drink these large volumes.
Urine alkalinization
Alkalinization of the urine enhances elimination of weak acids (eg, salicylates, phenobarbital). A solution made by combining 1 L of 5% D/W with three 50-mEq (50-mmol/L) ampules of sodium bicarbonate and 20 to 40 mEq (20 to 40 mmol/L) of potassium can be given at a rate of 250 mL/h in adults and 2 to 3 mL/kg/h in children. Urine pH is kept at ≥ 7.5). A solution made by combining 1 L of 5% D/W with three 50-mEq (50-mmol/L) ampules of sodium bicarbonate and 20 to 40 mEq (20 to 40 mmol/L) of potassium can be given at a rate of 250 mL/h in adults and 2 to 3 mL/kg/h in children. Urine pH is kept at ≥ 7.5, and potassium must be repleted. Hypernatremia, alkalemia, and fluid overload may occur but are usually not serious. Urine alkalinization is contraindicated in patients with renal insufficiency (5).
Dialysis
Common toxins that may require dialysis or hemoperfusion include:
Ethylene glycol
Lithium
Methanol
Salicylates
Theophylline
These therapies are less useful if the poison is a large or charged (polar) molecule, has a large volume of distribution (ie, if it is stored in fatty tissue), or is extensively bound to tissue protein (as with digoxin, phencyclidine, phenothiazines, or tricyclic antidepressants). The need for dialysis is usually determined by laboratory values, clinical status, and the toxin involved. Methods of dialysis include hemodialysis and hemoperfusion.
Specific antidotes
For the most commonly used antidotes, see table Common Specific Antidotes. IV lipid emulsions in 10% and 20% concentrations and high-dose insulin therapy have been used to successfully treat several different cardiac toxins (eg, bupivacaine, diltiazem, , diltiazem,verapamil) (6).
Common Specific Antidotes
Toxin | Antidote |
|---|---|
AcetaminophenAcetaminophen | N-acetylcysteine |
Anticholinergics | Physostigmine*Physostigmine* |
Anticoagulants, oral factor Xa inhibitors (apixaban, edoxaban, rivaroxaban)Anticoagulants, oral factor Xa inhibitors (apixaban, edoxaban, rivaroxaban) | Andexanet alfa |
Benzodiazepines | Flumazenil*Flumazenil* |
Black widow spider bite | Lactrodectus antivenom |
Botulism | Botulinum antitoxin |
Beta-blockers | GlucagonGlucagon IV lipid emulsion |
Calcium channel blockers | Calcium IV insulin in high doses with IV glucoseIV insulin in high doses with IV glucose IV lipid emulsion |
Carbamates | AtropineAtropine Pralidoxime chloridePralidoxime chloride |
Crotaline snake bites (United States) | Crotalinae polyvalent immune Fab (ovine) |
Cyanide | HydroxocobalaminHydroxocobalamin Cyanide antidote kit (includes amyl nitrate, sodium nitrite, and sodium thiosulfate)Cyanide antidote kit (includes amyl nitrate, sodium nitrite, and sodium thiosulfate) |
DabigatranDabigatran | IdarucizumabIdarucizumab |
Digitalis glycosides (eg, digoxin, digitoxin, oleander, foxglove)Digitalis glycosides (eg, digoxin, digitoxin, oleander, foxglove) | Digoxin-specific Fab fragmentsDigoxin-specific Fab fragments |
Ethylene glycol | FomepizoleFomepizole Ethanol Ethanol |
Heavy metals | Chelating agents (see table Guidelines for Chelation Therapy) |
Ionizing radiation | Potassium iodidePotassium iodide |
Iron | DeferoxamineDeferoxamine |
IsoniazidIsoniazid | Pyridoxine (vitamin B6)Pyridoxine (vitamin B6) |
Methanol | FomepizoleFomepizole Ethanol Ethanol |
Methemoglobin-forming agents (eg, aniline dyes, some local anesthetics, nitrates, nitrites, phenacetin, sulfonamides) | Methylene blueMethylene blue |
MethotrexateMethotrexate | Leucovorin (folinic acid) Leucovorin (folinic acid) Glucarpidase (carboxypeptidase-G2)Glucarpidase (carboxypeptidase-G2) |
Opioids | NaloxoneNaloxone |
Organophosphates | AtropineAtropine PralidoximePralidoxime |
Scorpion envenomation (Centruroides sp) | Centruroides immune F(ab’)2 |
Sulfonylurea | OctreotideOctreotide |
Thallium | Prussian blue |
Tricyclic antidepressants | Sodium bicarbonateSodium bicarbonate |
Unfractionated heparinUnfractionated heparin | ProtamineProtamine |
Valproic acidValproic acid | L-Carnitine† |
WarfarinWarfarin | Vitamin K Fresh frozen plasma Prothrombin complex concentrate (PCC)Prothrombin complex concentrate (PCC) |
* Use is controversial because toxicity may result if indications, administration, and monitoring are not appropriate. Consultation with a medical toxicologist is recommended. | |
† There is limited evidence for the efficacy of L-carnitine as a general antidote for acute valproic acid overdose. However, L-carnitine is likely to be safe and it is reasonable to consider using it in patients with decreased level of consciousness.There is limited evidence for the efficacy of L-carnitine as a general antidote for acute valproic acid overdose. However, L-carnitine is likely to be safe and it is reasonable to consider using it in patients with decreased level of consciousness. | |
Fab = fractionated antibodies. | |
Chelation
Chelating agents are used for poisoning with heavy metals and occasionally with other drugs or medications (see table Guidelines for Chelation Therapy).
Guidelines for Chelation Therapy
Chelating Agent* | Metal | Dosage† |
|---|---|---|
Deferasirox/deferiprone/deferoxamineDeferasirox/deferiprone/deferoxamine | Iron | |
Dimercaprol, 10% in oilDimercaprol, 10% in oil | Antimony Arsenic Bismuth Copper saltsCopper salts Gold Lead Mercury Thallium* | 3–4 mg/kg via deep IM injection every 4 hours on day 1; 2 mg/kg IM every 4 hours on day 2; 3 mg/kg IM every 6 hours on day 3; then 3 mg/kg IM every 12 hours for 7–10 days until recovery |
Edetate calcium disodium (calcium disodium edathamil) diluted to Edetate calcium disodium (calcium disodium edathamil) diluted to≤ 3% | Cobalt Lead Zinc Zinc saltsZinc salts | 25–35 mg/kg via deep IM injection or IV slowly (over 1 hour) every 12 hours for 5–7 days, followed by 7 days without the medication; then repeated |
PenicillaminePenicillamine | Arsenic Copper saltsCopper salts Gold Lead | 5–7.5 mg/kg orally 4 times a day (usual starting dose is 250 mg 4 times a day) to a maximum adult dose of 2 g/day |
SuccimerSuccimer | Arsenic (occupational exposure in adults) Cadmium salts Lead if children have blood lead levels > 45 mcg/dL (> 2.15 micromol/L) Lead (occupational exposure in adults) Mercury (occupational exposure in adults) | 10 mg/kg orally every 8 hours for 5 days, then 10 mg/kg orally every 12 hours for 14 days |
Triethylenetetramine | CopperCopper | Dosing for Wilson disease only‡ 13 years and older: 750–1250 mg, orally, in divided doses given 2, 3, or 4 times daily; maximum dose: 2000 mg daily 12 and under: 500–750 mg, orally, in divided doses given 2, 3, or 4 times daily; maximum dose: 1500 mg daily |
* Thallium salts are chelated with varying success by this medication (see thallium salts in table Symptoms and Treatment of Specific Poisons). | ||
† Dosages depend on type and severity of poisoning. | ||
‡ This chelating agent was approved in 2018 for treatment of Wilson disease; it was not approved for use in the treatment of exogenous copper intoxication. This chelating agent was approved in 2018 for treatment of Wilson disease; it was not approved for use in the treatment of exogenous copper intoxication. | ||
Ongoing supportive measures
Most symptoms (eg, agitation, sedation, coma, cerebral edema, hypertension, arrhythmias, renal failure, hypoglycemia) are treated with the usual supportive measures.
Drug-induced hypotension and arrhythmias may not respond to the usual medication treatments. Dopamine, epinephrine, other vasopressors, an intra-aortic balloon pump, or even extracorporeal circulatory support may be considered for refractory hypotension.Drug-induced hypotension and arrhythmias may not respond to the usual medication treatments. Dopamine, epinephrine, other vasopressors, an intra-aortic balloon pump, or even extracorporeal circulatory support may be considered for refractory hypotension.
Cardiac pacing may be necessary for refractory arrhythmias. Often, torsades de pointes can be treated with magnesium sulfate 2 to 4 g IV, overdrive pacing, or a titrated isoproterenol infusion.Cardiac pacing may be necessary for refractory arrhythmias. Often, torsades de pointes can be treated with magnesium sulfate 2 to 4 g IV, overdrive pacing, or a titrated isoproterenol infusion.
Seizures are first treated with benzodiazepines. Phenobarbital and propofol have been used when benzodiazepines are ineffective. Severe agitation must be controlled; benzodiazepines in large doses, other potent sedatives (eg, propofol), or, in extreme cases, induction of paralysis and mechanical ventilation may be required.Seizures are first treated with benzodiazepines. Phenobarbital and propofol have been used when benzodiazepines are ineffective. Severe agitation must be controlled; benzodiazepines in large doses, other potent sedatives (eg, propofol), or, in extreme cases, induction of paralysis and mechanical ventilation may be required.
Hyperthermia is treated with aggressive sedation and physical cooling measures rather than with antipyretics. Organ failure may ultimately require kidney transplantation or liver transplantation.
Hospital admission
General indications for hospital admission include altered consciousness, persistently abnormal vital signs, and predicted delayed toxicity. For example, admission is considered if patients have ingested sustained-release preparations, particularly of drugs or medications with potentially serious effects (eg, cardiovascular medications). If there are no other reasons for admission, if indicated laboratory test results are normal, and if symptoms are gone after patients have been observed for 4 to 6 hours, most patients can be discharged. However, if ingestion was intentional, patients require a psychiatric evaluation.
Treatment references
1. Mohamed F, Sooriyarachchi MR, Senarathna L, et al. Compliance for single and multiple dose regimens of superactivated charcoal: a prospective study of patients in a clinical trial. . Compliance for single and multiple dose regimens of superactivated charcoal: a prospective study of patients in a clinical trial.Clin Toxicol (Phila). 2007;45(2):132-135. doi:10.1080/15563650600981145
2. Position statement and practice guidelines on the use of multi-dose activated charcoal in the treatment of acute poisoning. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. J Toxicol Clin Toxicol. 1999;37(6):731-751. doi:10.1081/clt-100102451
3. Benson BE, Hoppu K, Troutman WG, et al. Position paper update: gastric lavage for gastrointestinal decontamination. Clin Toxicol (Phila). 2013;51(3):140-146. doi:10.3109/15563650.2013.770154
4. Thanacoody R, Caravati EM, Troutman B, et al. Position paper update: whole bowel irrigation for gastrointestinal decontamination of overdose patients. Clin Toxicol (Phila). 2015;53(1):5-12. doi:10.3109/15563650.2014.989326
5. Proudfoot AT, Krenzelok EP, Vale JA. Position Paper on urine alkalinization. J Toxicol Clin Toxicol. 2004;42(1):1-26. doi:10.1081/clt-120028740
6. Gosselin S, Hoegberg LC, Hoffman RS, et al. Evidence-based recommendations on the use of intravenous lipid emulsion therapy in poisoning. Clin Toxicol (Phila). 2016;54(10):899-923. doi:10.1080/15563650.2016.1214275
Prevention of Poisoning
In the United States, widespread use of child-resistant containers with safety caps has greatly reduced the number of poisoning deaths in children < 5 years. Limiting the amount of over-the-counter (OTC) analgesics in a single container and eliminating confusing and redundant formulations reduces the severity of poisonings, particularly with acetaminophen, aspirin, or ibuprofen.
Other preventive measures include:
Clearly labeling household products and prescription medications
Storing medications and toxic substances in cabinets that are locked and inaccessible to children
Promptly disposing of expired medications by mixing them in cat litter or some other nontempting substance and putting them in a trash container that is inaccessible to children
Using carbon monoxide detectors
Refraining from prescribing opioids and using nonopioid treatments whenever possible
Public education measures to encourage storage of substances in their original containers (eg, not placing insecticides in drink bottles) are important. Use of imprint identifications on solid medications helps prevent confusion and errors by patients, pharmacists, and health care professionals.
Key Points
Poisoning is distinguished from hypersensitivity and idiosyncratic reactions, which are unpredictable and not dose-related, and from intolerance, which is a toxic reaction to a usually nontoxic dose of a substance.
Recognizing a toxidrome (eg, anticholinergic, muscarinic cholinergic, nicotinic cholinergic, opioid, sympathomimetic, withdrawal) can help narrow the differential diagnosis.
Toxicity may be immediate, delayed (eg, acetaminophen, iron, Amanita phalloides mushrooms causing delayed hepatotoxicity), or occur only after repeated exposure.
Maximize recognition of poisoning and identification of the specific poison by considering poisoning in all patients with unexplained alterations in consciousness and by searching thoroughly for clues from the history.
Consider other causes (eg, central nervous system infection, head trauma, hypoglycemia, stroke, hepatic encephalopathy, Wernicke encephalopathy) if consciousness is altered, even if poisoning is suspected.
Use toxicology testing (eg, drug immunoassays) selectively because it can provide incomplete or incorrect information.
Treat all poisoning supportively and use activated charcoal for serious oral poisoning and other methods selectively.Treat all poisoning supportively and use activated charcoal for serious oral poisoning and other methods selectively.
More Information
The following English-language resources may be useful. Please note that The Manual is not responsible for the content of this resource.
Chemical Companion (ERDSS). Available as both a tablet app and downloadable software.
U.S. Department of Health and Human Services. Chemical Hazards Emergency Medical Management. Available as downloadable software.
U.S. Department of Transportation (DOT) Pipeline and Hazardous Materials Safety Administration. Emergency Response Guidebook. Available as a downloadable document and a mobile application.
National Oceanic and Atmospheric Administration. CAMEO Chemicals. Available as a mobile application and downloadable software
