Abstract: See related article, p. 290 . The evaluation of children who have ingested a potential overdose of acetaminophen has included the standard practice of waiting until at least 4 hours after ingestion to draw blood for determination of a drug level. This was based on the work performed in several centers in the middle 1970s, primarily in adults.1Peterson RG Rumack BH. Pharmacokinetics of acetaminophen in children.Pediatrics. 1978; 62: 877-879PubMed Google Scholar The initial level, when related to time, has been used to determine the likelihood of toxicity, and hence, whether n-acetylcysteine should be administered. The concern with determining levels earlier was that incomplete absorption could result in a delayed higher level, which might be missed and thus result in non-treatment of individuals who should have such therapy. Prolongation of absorption is related primarily to various co-ingestants that delay gastric emptying. At the time these recommendations were made, the combination of propoxyphene and acetaminophen was widely used. Significant delays were seen from ingestion to peak level with this drug and others in the opiate class or related classes. Antihistamines, food, and various other agents were of concern. Because we believed that these patients were going to be in a hospital environment for some time, delaying the determination of a drug level did not seem to be a significant problem. The article in this issue of The Journal by Anderson et al2Anderson BJ Holford NHG Armishaw JC Aicken R. Predicting concentrations in children presenting with acetaminophen overdose.J Pediatr. 1999; 135: 290-295Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar raises questions about this practice and provides data that are sufficient to allow us to question this method. The most obvious point made in this article is that children are more likely to receive a liquid form of the medication with concomitant rapid absorption. Virtually all of the adult data used to establish standard protocols involved patients who consumed tablets or capsules. The absorption half-lives and peak concentrations in children who have ingested liquid preparations are certainly rapid enough to justify determining a level earlier than 4 hours. The authors suggest a reasonably conservative 2-hour wait until such measurements are made, which should be more than adequate given the available data. The kinetic modeling provided by the authors allows extension beyond the simple question of measurement of acetaminophen levels. Prevention of absorption is also addressed. This issue has been an object of intense debate over the past 2 decades. Induced vomiting, catharsis, and lavage, as well as the administration of activated charcoal, have been used for many years. These methods, which future generations of physicians may consider to be barbaric, are gradually being abandoned. Syrup of Ipecac is still sold regularly in pharmacies and even in home improvement stores next to child safety devices. Ipecac has no place at all in modern therapy. Although the results of administration may be quite spectacular, the recovery of ingested material is not significant and the complications are potentially harmful. Lavage has progressed from the use of 12F tubes (which washed off the coatings of medications and increased absorption) to the use of 40F tubes made popular at the Royal Infirmary of Edinburgh, to being an outmoded and abandoned procedure. The elegant work by Kulig et al,3Kulig K Bar-Or D Cantrill SV Rosen P Rumack BH. Management of acutely poisoned patients without gastric emptying.Ann Emerg Med. 1985; 14: 562-567Abstract Full Text PDF PubMed Scopus (247) Google Scholar more than a decade ago, clearly demonstrated the lack of value of lavage. Catharsis, ranging from administration of Epsom salts to massive amounts of hypertonic fluids, has only a minimal benefit and carries the risk of dehydration in children. The authors correctly point out the time course and probable lack of effectiveness. Such lack of benefit of charcoal and emesis in cases of acetaminophen overdose has been previously suggested.4Peterson RG Rumack BH. Acetaminophen overdose.in: 9th ed. Current pediatric therapy. WB Saunders, Philadelphia1980: 680-681Google Scholar Whether activated charcoal provides benefit after ingestion of acetaminophen tablets and capsules and other medications and agents requires continued study. In regard to prevention of absorption, we seem to have believed that “doing something” is critical and apparently find the visible results of emetics, cathartics, and other such agents to be satisfying. The decrease in the incidence of these procedures is related to numerous published studies, which examine the lack of recovery of ingested toxic agents. The child with acetaminophen ingestion needs a careful and rational evaluation. A history may be a very unreliable part of the equation. Sometimes we do not know how much was in the bottle, and sometimes we do not know how much has been spilled. We rarely really know the amount ingested or absorbed. Anderson et al2Anderson BJ Holford NHG Armishaw JC Aicken R. Predicting concentrations in children presenting with acetaminophen overdose.J Pediatr. 1999; 135: 290-295Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar recommend an ingestion of 250 mg/kg elixir as the point at which a drug level should be determined. Given the difficulties with histories, it would be appropriate to be more conservative with this requirement if there is any question about the dose consumed. The only way to accurately determine the potential severity of such an event is to determine a drug level. The authors have given us sufficient data to convince us to determine that level earlier than before and shorten the time until a decision is made. Although we are fortunate that children have less toxicity at the same level as an adult, we must evaluate those with potential risk and provide treatment as appropriate. The conservative figure of 225 mg/L at 2 hours should provide the margin of safety required for this change in our standard treatment.
Publication Year: 1999
Publication Date: 1999-09-01
Language: en
Type: letter
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 15
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