- Camphor is present in many over-the-counter liniments and cold preparations. As little as 1 g has been reported to cause death in an 18-month-old child. Clinical camphor toxicity occurs rapidly, with onset 5 to 120 minutes after ingestion. Muscle twitching and fasciculation may herald the onset of seizures. Management of camphor ingestion is generally supportive, emphasizing airway protection and seizure control.
- Benzocaine, present in many local anesthetics, can cause methemoglobinemia, especially in infants younger than 4 months. Clinical signs and symptoms of benzocaine toxicity, which begin as early as 30 to 60 minutes after ingestion, include a characteristic cyanosis that does not respond to oxygen. Treatment of benzocaine-induced methemoglobinemia consists of general support and, in selected cases, administration of the antidote methylene blue.
- Lomotil is an antidiarrheal preparation that combines an opiate (diphenoxylate) with an anticholinergic (atropine). After ingestion, respiratory depression can recur as late as 24 hours and there appears to be no correlation between dose ingested and severity of symptoms. Therefore, any child with known or suspected ingestion of any amount of Lomotil is admitted and monitored for at least 24 hours, no matter what the initial clinical condition.
- Chloroquine, an antimalarial agent, is a powerful, rapidly acting cardiotoxin capable of causing sudden cardiorespiratory collapse. The interval between ingestion and cardiac arrest is often less than 2 hours.
- Methyl salicylate is a concentrated liquid that is absorbed quickly and can produce early-onset severe salicylate toxicity. Ingestion of less thanone teaspoon has been fatal in a child.
Fortunately, the overwhelming majority of toxic exposures in young children are not life-threatening. For example, using data from 2006, the National Poison Data System of the American Association of Poison Control Centers reported over a half a million exposures in children younger than 2 years of age, but only 16 fatalities.1 In addition, most medications that cause serious consequences in toddlers do so only after ingestion of clearly excessive amounts. Because so many pediatric toxic exposures turn out to be innocuous, it is easy for the clinician to become complacent about these cases, especially if by history the child ingested at most 1U dose of a medication. However, there are a number of prescriptions and over-the-counter preparations that can cause extreme toxicity, even fatality, in a toddler after ingestion of a single dose.2,3 The emergency physician must be familiar with these highly toxic agents.
This chapter will not discuss certain nonmedicinal agents such as hydrocarbons, acetonitrile, caustics, methanol, selenious acid, or environmental toxins that can also be extremely toxic in small amounts. Additionally, it will not be an exhaustive discussion of all possible relevant pharmaceuticals. For example, some highly toxic drugs, such as β-blockers and calcium channel blockers are not discussed here, but are covered in separate chapters of this text.4,5
Camphor is present in many over-the-counter liniments and cold preparations, such as Campho-Phenique, Ben-Gay, Vicks Vaporub, Absorbine, and Tiger Balm.3,...