The cornerstone of management of patients with a suspected overdose is supportive care, with particular attention to the airway, breathing, and circulation. Resuscitative measures are instituted prior to antidotal therapy or gastric decontamination (Fig. 107–1).
General approach to the poisoned patient.
In children with an altered level of consciousness or in whom a bedside glucose oxidase test documents hypoglycemia, the physician should administer intravenous dextrose at 0.5 to 1.0 g/kg, given as 2 to 4 mL/kg of D25 W in children or 50 mL (1 ampul) of D50 W in the adolescent. If intravenous access is difficult or unobtainable, glucagon, 1 mg, is administered intramuscularly.
In addition to dextrose, naloxone is given to children or adolescents with lethargy or coma. Naloxone is a specific opiate antagonist with minimal side effects. Agitation and signs of withdrawal may develop in opiate-dependent adolescents or in neonates whose mothers are narcotic addicts or on methadone during pregnancy. The initial dose is 0.1 mg/kg intravenously or 2 mg for children weighing >20 kg. Often, additional doses of naloxone are required for certain opiates, such as fentanyl, codeine, methadone, and propoxyphene, which have high potency and a prolonged half-life.7 If an intravenous line cannot be established, naloxone may be administered via the endotracheal tube, intramuscularly, intralingually, or subcutaneously.8
Gastrointestinal decontamination is one of the more controversial topics in toxicology. Whether patients are managed with gastric lavage, whole bowel irrigation, or activated charcoal alone depends on the toxicity of the particular drug, the quantity and time of ingestion, and patient's condition. If children ingest a nontoxic agent or a very small amount of a poison unlikely to cause toxicity, no gastric decontamination measures are necessary. However, if the ingestion is recent and the child is symptomatic, or the ingested toxin may cause delayed toxicity, gastric decontamination is generally recommended. Several clinical trials have been conducted to determine which of the gastric decontamination modalities are most efficacious. However, the investigations either involve adult volunteers, who ingested subtoxic amounts of an agent and received decontamination at a set postingestion time, or involve mild-to-moderately poisoned patients, and exclude patients with significant overdoses. Few children have been included in these trials. Therefore, these studies must be critically interpreted prior to their definitive application in the clinical setting, especially in the pediatric patient. Most treatment modalities have focused on stomach evacuation, while the ultimate goal should be to decontaminate the entire gastrointestinal tract.9,10
Historically, syrup of ipecac was the most commonly used gastric decontamination agent (Fig. 107–2). It is a mixture of alkaloids consisting of emetine and cephaeline, which are strong emetic agents that stimulate the gastric mucosa as well as the brain's chemoreceptor trigger zone. Ipecac gained popularity for home use in pediatric poisonings in the 1960s.11,12 However, its use has fallen out of favor in the emergency department and prehospital settings and is no longer advocated in the heath care setting for treatment of the acutely poisoned patient. In 1985, it was given in 15% of all oral exposures reported to poison control centers. In 2006, it was administered in only 0.1% of the cases.1
Routine induction of emesis with syrup of ipecac is no longer recommended.
Ipecac can be expected to induce vomiting within 20 to 60 minutes. The recovery of ingested material in the vomitus is approximately 30% if ipecac is administered within 5 minutes of ingestion, and far less if delayed beyond 1 hour. Most children will experience up to three episodes of vomiting, which often delays the administration of activated charcoal. In human volunteer studies, ipecac was not able to significantly decrease absorption of drugs after 30 to 60 minutes and was inferior when compared to activated charcoal alone.
Ipecac is contraindicated in children younger than 6 months, in patients with evidence of a diminished gag reflex and potential for coma or seizures, and in the ingestion of most hydrocarbons, acids, alkalis, and sharp objects. Complications following ipecac use that have been reported in the literature include aspiration pneumonia, dehydration due to protracted vomiting, diaphragmatic rupture and death, Mallory-Weiss tears of the esophagus, and gastric rupture.13–15
The use of ipecac is no longer recommended by the American Academy of Pediatrics or the American Association of Poison Centers for use in the emergency setting. Research has demonstrated no improvement in clinical outcome with its use.15 There is also no accepted role for syrup of ipecac in the prehospital management of poisonings. The American Academy of Pediatrics issued a statement that ipecac should no longer be used routinely as a home treatment strategy, that existing ipecac in the home should be disposed of safely.16 There has been no reduction in resource usage or improvement in patient outcome from the use of syrup of ipecac at home.13
Ideally, gastric lavage mechanically removes toxins from the stomach through a large-bore orogastric tube. In pediatric patients, the size of the lavage tube ranges from 16 to 32 Fr, depending on the age of the patient. In fact, gastric lavage removes, at best, up to 40% of the ingested toxin. In some cases, the holes at the end of the evacuation tube are too small to allow pill fragments to be suctioned into the lavage tube lumen (Fig. 107–3). It is important to note that gastric lavage does not remove toxic agents from the intestinal tract, where the majority of drug absorption occurs. It is also important to realize that there have been no clinical trials evaluating the efficacy of gastric lavage in small children.10
Even large-bore gastric lavage tubes may not have sufficient size to aspirate pills and medication fragments.
Gastric lavage should not be routinely performed in overdosed pediatric patients.17 Gastric lavage may be considered if a patient has ingested a potentially life-threatening amount of a toxin and presents within 1 hour of ingestion.17–21 However, even in this scenario, there is no clear evidence that its use improves clinical outcome. Airway protection by endotracheal intubation prior to the lavage is indicated in children with a depressed level of consciousness to order to avoid aspiration pneumonitis. In these cases, the risk of intubation must be weighed against the potential benefits of gastric lavage. Gastric lavage should never be used as a punitive measure in cases of nontoxic overdoses or forced on pediatric patients who are combative or otherwise uncooperative. Additionally, endotracheal intubation solely to perform gastric lavage is discouraged; the decision to intubate should be independently of the decision to perform gastric lavage.
With gastric lavage, after verifying proper orogastric tube placement, the stomach contents are aspirated, then irrigated with 50 to 100 mL aliquots of normal saline until the returned lavage fluid is clear; in adolescents, 250 mL aliquots are recommended. In patients in whom lavage may be indicated, it is theoretically attractive to give charcoal down the tube immediately upon insertion, followed by lavage, followed by charcoal. This obviously would not apply to drugs not bound to charcoal, but it does address the concern that process of lavage moves drugs from the stomach into the small intestine, thereby enhancing absorption. Theoretically, the charcoal administered prior to lavage binds to drug that would be forced through the pylorus by the lavage fluid, limiting the drug's absorption.
If the child has recently ingested an elixir or liquid, a simple nasogastric tube is adequate in order to avoid orogastric injury from traumatic insertion of a large-bore tube. Although controversial, there may be some efficacy for lavage beyond 1 hour when the agent ingested slows gut motility, such as with anticholinergics or opioids, or when the toxin forms concretions, such as with iron and salicylates. However, this has never been substantiated in the toxicology literature.10
Gastric lavage is contraindicated in ingestions of most hydrocarbons, acids, alkalis, and sharp objects. Although relatively safe when performed properly, it is not a benign procedure and complications including aspiration, esophageal perforation, bleeding, electrolyte imbalance, and hypothermia have been described. Therefore, the clinician must have adequate rationale to perform this gastric decontamination procedure.
The majority of poisoned children who are not critically ill can be managed safely and effectively in the emergency department setting with charcoal alone. Activated charcoal is an odorless, tasteless, fine black powder that is effective in adsorbing many toxins.22 Recent charcoal products have been “superactivated” resulting in large surface areas of up to 3000 m2/g, allowing for maximum absorptive power.
Activated charcoal is the most frequently used and most effective gastrointestinal decontamination agent. Evidence suggests that activated charcoal is more effective than induced emesis or gastric lavage for gastric decontamination.23 Activated charcoal can be administered rapidly and is most beneficial when administered within 1 hour after the ingestion. The absorptive properties of activated charcoal are effective beyond the gastric mucosa; absorbing drugs throughout the small intestine. While studies have demonstrated reduced drug absorption with activated charcoal use, it is important to note that there is no evidence that administration of activated charcoal ultimately improves patient outcome.23,24 Its routine administration in nontoxic ingestions is not indicated.
Most young children will refuse to drink charcoal due to its gritty texture and threatening appearance (Fig. 107–4). Children can be distracted by administrating the charcoal in an opaque styrofoam cup with a lid and straw, or by adding favoring to enhance its palatability. Additionally, medical personnel may allow reliable parents to administer the charcoal to the child. Occasionally, a patient may be unable to or may refuse to drink charcoal. In these scenarios, when charcoal is clearly indicated, a small nasogastric tube may need to be inserted in order to facilitate its administration.
Although safe and effective, activated charcoal administration may be a challenge in younger pediatric patients.
Although most sources recommend an activated charcoal dose of 1 mg/kg, if the amount of drug ingested is known, a more accurate dose of activated charcoal can be calculated using a 10:1 ratio of charcoal to the ingested toxin. However, even this 10:1 ratio, although adequate in most scenarios, has never been shown to be as efficacious or superior to larger ratios. Practically speaking, most pediatric patients will not tolerate larger doses of activated charcoal.
For some drugs, such as theophylline, phenobarbital, and carbamazepine, multiple dosing of activated charcoal may enhance elimination due primarily to enteroenteric circulation of the drug (Table 107–10).25 Repeated use of charcoal preparations premixed with cathartics such as sorbitol is to be avoided, since dehydration and electrolyte imbalance may result.
Table 107-10. Agents Responsive to Multiple Doses of Activated Charcoal |Favorite Table|Download (.pdf)
Table 107-10. Agents Responsive to Multiple Doses of Activated Charcoal
Substances adsorbable by activated charcoal (ABCD)
Antimalarials (quinine), Aminophylline (theophylline)
Substances not adsorbable by activated charcoal (PHAILS)
Acids, alkali, alcohols
Activated charcoal is the preferred mode of gastrointestinal decontamination when the history of the overdose or time of ingestion is unclear, since delayed administration may be beneficial, with minimal adverse side effects. Rare cases of vomiting, constipation, obstruction, and aspiration have been reported, but the incidence, particularly in pediatric cases, is extremely low.24,26,27 The administration of activated charcoal in the home or prehospital setting is gaining popularity as a superior substitute for syrup of ipecac.2,28 Activated charcoal is neither effective nor indicated in heavy metal poisonings, such as with iron, lithium, or borates; ingestions of ethanol containing products; or following ingestion of acids or alkalis where gastric visualization or endoscopy may be required (Table 107–10).
Cathartics are osmotically active agents that eliminate toxins from the gastrointestinal tract by inducing diarrhea. The most common agents are sorbitol, magnesium citrate, and magnesium sulfate (Fig. 107–5). Historically, it was recommended that one dose of a cathartic be administered with the first dose of charcoal in order to reduce the gastrointestinal transit time of the toxin–charcoal mixture. However, the efficacy of cathartic use in reducing the absorption or increasing the elimination of toxins has not been established.29 There is no published data demonstrating an improved outcome with cathartic use alone or combined with activated charcoal.29 Studies investigating the use of sorbitol in combination with activated charcoal have found that it enhances charcoal's palatability. As a result, younger children are more accepting of its oral administration. In the pediatric population, cathartic agents have been reported to result in hypermagnesemia, severe dehydration, and electrolyte imbalances if used excessively or in repetitive doses.30 In young children, it is recommended that activated charcoal be administered with water only, without any cathartic agent.
Cathartic agents can cause severe electrolyte and fluid disturbances and are not recommended in children.
Originally used as a preoperative bowel preparation, whole bowel irrigation (WBI) is now used in the overdose setting to “flush” the toxin through the gastrointestinal tract and prevent further absorption. In theory, it may also produce a concentration gradient that allows previously absorbed toxins to diffuse back into the gastrointestinal tract.31 The solution used is nonabsorbable, isotonic polyethylene glycol electrolyte (PEG) solution that, unlike cathartic agents, does not appear to create fluid or electrolyte disturbances (Fig. 107–6). The dose is 100 to 200 mL/h for small children and 1 to 2 L/h for adolescents. The irrigation process is continued until the rectal effluent is clear, usually within 4 to 6 hours.
Polyethylene glycol solution is an osmotically neutral and electrolyte safe solution used for whole bowel irrigation with selected poisons.
While volunteer studies have demonstrated decreased bioavailability of certain drugs using WBI, there is currently no conclusive evidence that WBI improves clinical outcome of poisoned patients.32 Although much of the evidence for WBI is anectdotal, this modality has been used in the pediatric population with minimal to no side effects. In patients who are hemodynamically stable and have normal bowel function and anatomy, it is reasonable to consider using WBI with specific ingestions. In case reports, it has been effective in ingestions not well absorbed by activated charcoal such as iron tablets,33–35 lead paint chips,36 lithium,37 and sustained released calcium channel blockers.38 With these cases, an abdominal radiograph demonstrating radioopacities can be followed in a serial manner to document the effectiveness of WBI. In addition, its use has been documented following cocaine and opiate packet ingestions. In agents well absorbed by charcoal, WBI is discouraged as it may actually decrease the efficacy of activated charcoal.39
Although the majority of poisonings in the pediatric population respond to supportive care and gastric decontamination alone, there are a few toxins that require antidotes.40 The purpose of antidotal therapy is to reduce the agent's toxicity by inhibiting the toxin at the effector site or target organ, to reduce the toxin's concentration, or to enhance its excretion. The number of effective antidotes is limited (Table 107–11) and is not for indiscriminate use. Antidotal therapy should be used carefully and in clinical circumstances when specifically indicated. Newly approved antidotes include fomepizole for toxic alcohols,41,42 CroFab for pit viper envenomations,43,44 dextrose–insulin therapy for calcium channel blockers,45,46 and hydroxycobalamin administration for cyanide poisoning.47,48
Table 107-11. Antidotes and Their Indications |Favorite Table|Download (.pdf)
Table 107-11. Antidotes and Their Indications
- Ethanol/fomepizole (4-MP)
- Atropine/pralidoxime (2-PAM)
- Methylene blue
- Dimercaprol (BAL)
- Succimer (DMSA)
- Fab fragments
- Sodium bicarbonate
- Dextrose, glucagons, octreotide
- Indication (agent)
- Methanol/ethylene glycol
- Carbon monoxide
- Arsenic, lead
- Lead, mercury
- Digoxin, Crotalids, Colchicine,
- β-Blockers, Calcium channel blockers
- Tricyclic antidepressants
- Calcium channel antagonists
- Oral hypoglycemics
Enhancing elimination is the process of removing a toxin from the body once absorption has already occurred. Methods of enhanced elimination include multiple-dose-activated charcoal, urinary alkalinization, and extracorporeal elimination. The role of multiple-dose-activated charcoal was discussed previously. Urinary alkalinization involves the use of an intravenous sodium bicarbonate infusion and promotes urinary elimination of substances that are weak acids. It is important to maintain a normal potassium level when performing alkalinization, since appropriate alkalinization cannot be achieved when hypokalemia is present. A common use of urinary alkalinization is in the salicylate-poisoned patient. Another use may be in patients who overdose on phenobarbital. As an aside, urinary acidification has been recommended in the past as a method of enhanced elimination with poisoning by weak bases, such as phencyclidine and amphetamine. This procedure is no longer recommended because of the high risk of myoglobinuria and rhabdomyolysis.3
Hemodialysis and Hemoperfusion
Although hemodialysis is recommended for a wide variety of toxins, it is necessary in only a few severely poisoned patients.49 Drugs that may be adequately dialyzed include those with a low molecular weight, low volume of distribution, low protein binding, and high water solubility. Examples include isopropanol, salicylates, theophylline, uremia-causing agents, methanol, barbiturates, lithium, and ethylene glycol (Table 107–12). Theophylline is also responsive to charcoal hemoperfusion. If children have a severe overdose that may require dialysis, early consultation with a nephrologist is critical.
Table 107-12. Toxins Accessible to Hemodialysis |Favorite Table|Download (.pdf)
Table 107-12. Toxins Accessible to Hemodialysis
No response to conventional therapy
Alcohols (isopropanol, methanol)
Boric acid, barbiturates (phenobarbital)
Enhanced elimination by charcoal hemoperfusion