Second-generation antihistamines: a study of poisoning in children.

Background and objectives: The toxicity of second-generation antihistamines after an overdose by a child is still unknown. The objective of this study is to use data from Poisons Centres in France to describe the toxicity profile of second-generation antihistamines for children and to compare the severity of poisoning observed from these with a first-generation antihistamine.Method: This was a retrospective, multi-centre and observational study focusing on human cases of single-substance exposure to a second-generation antihistamine and to mequitazine, reported between 1 January 2001 and 31 December 2016 in Poisons Centres in France.Results: From a total of 9403 children included, 5980 were exposed to a second-generation antihistamine and 3423 were exposed to mequitazine. The severity of exposure to second-generation antihistamines in children is low: among the children followed until a known outcome, 9% of children were symptomatic and in 97% of cases, the symptoms shown were of a minor-level severity (primarily drowsiness or restlessness). Depending on the substance, children who ingested doses 16 to 69 times the maximum recommended therapeutic dose remained asymptomatic. No deaths or severe symptoms were observed. No cases of lengthening of the QT interval or arrhythmias were identified. Mequitazine led to more symptoms than other substances (14.8% symptomatic children vs. 7.5%, Odd ratio (OR): 2.3 (2.0-2.6), p < 0.0001), more symptoms of moderate intensity (1.4 vs. 0.2%, OR: 8.3 (4.1-18.5), p < 0.0001) and more hospitalisation (19.1 vs. 8.7%, OR: 2.5, 95% CI: (2.2-2.8), p < 0.0001).Conclusion: The severity of poisoning from second-generation antihistamines appears to be low among children and considerably lower than poisoning caused by mequitazine.

A Danish Survey of Antihistamine Use and Poisoning Patterns.

The first-generation antihistamine, promethazine, became a prescription-only drug in Denmark as of December 2014. First-generation antihistamines are known to have a higher toxic potential than second-generation antihistamines. The aim of this study was to provide a nationwide description of the antihistamine use and poisoning pattern from 2007 to 2013 in Denmark based on two independent databases. There were 1049 antihistamine exposures in the national, advisory telephone service specialized in poisonings, the Danish Poison and Information Centre (DPIC), and 456 exposures in the three registers used within the State Serum Institute of Denmark (SSI), a department under the Danish Ministry of Health dealing with research-based health surveillance in Denmark. First-generation antihistamines constitute 61% and 73% of antihistamine registrations in DPIC and SSI, respectively. Antihistamine exposures increased by 7 exposures/10,000 enquiries per year in DPIC and six admissions per year in SSI - this increase is not significant due to a sudden decrease in 2012. Intentional exposures constituted 65% in DPIC of which 82% was due to suicide attempts, and 78% of the involved antihistamines were first-generation antihistamines. Accidental exposures constituted 33% of which 61% were due to play and 29% involved first-generation antihistamines. Single antihistamine exposures constituted 65% of DPIC exposures of which 98% involved only one brand of antihistamine. Multidrug exposures constituted 35% of DPIC exposures with equally distributed coingestants. Hospitalization was recommended in 78% of DPIC exposures. Admissions required only 1-day of treatment in 91% of the SSI exposures. One of the 14 identified deaths in the SSI study population was directly related to antihistamine poisoning. Results support the limited disclosure of promethazine in Denmark and illustrate a generation-specific pattern indicating a suspected replacement of promethazine with other first-generation antihistamines.

Nomogram line crossing after acetaminophen combination product overdose.

BACKGROUND: The Rumack-Matthew nomogram predicts the risk of hepatotoxicity following acute acetaminophen overdose based on a serum concentration obtained ≥ 4-hour post-ingestion. Some patients with low-risk concentrations at 4 hours may have subsequent values indicating increased risk (above the nomogram treatment line), especially if coingestants that slow gastrointestinal motility are involved. The treatment line currently used to identify low risk patients in the United States, Canada, and Australia begins at 150 mcg/mL (993 µmol/L) and intersects at 18.75 mcg/mL (124.1 µmol/L) 16 hours post-ingestion. OBJECTIVE: To determine the incidence of nomogram line crossing after acute overdose of acetaminophen combination products containing an opioid or antihistamine. METHODS: This was a prospective cohort study of hospitalized patients reported to a regional poison center (RPC) after acute overdose of a combination product containing an opioid or antihistamine. If a 4-hour acetaminophen concentration was detectable but below the nomogram treatment line, the RPC recommended repeat concentrations. Patients were entered into the study if at least one subsequent concentration was available. During follow-up calls hospital providers were queried regarding clinical features, treatment, and indicators of liver injury. RESULTS: Over a 4-year period 76 patients met entry criteria. 5/76 (6.6%) had measureable acetaminophen concentrations below the treatment line at or close to 4-hour post-ingestion followed by values above the line obtained at 6.5-12.5 hours. Four of the five were treated with acetylcysteine and none developed hepatotoxicity. Four of the five had clinical features reported to the RPC suggesting toxicity from the opioid or antihistamine component. CONCLUSION: After acute overdose of acetaminophen combination products, patients with detectable but non-toxic 4-hour acetaminophen concentrations should have repeat concentrations obtained in a time frame that would allow providers to initiate acetylcysteine treatment, if needed, without undue delay.

Effect of cough and cold medication restriction and label changes on pediatric ingestions reported to United States poison centers.

OBJECTIVE: To determine the impact of industry and Food and Drug Administration initiatives implemented to limit the use of over-the-counter (OTC) cough and cold medications in children younger than 6 years of age. STUDY DESIGN: This is a retrospective database study of OTC cough and cold medication ingestions reported to US poison centers between 2000 and 2010. Data analyzed from the National Poison Data System included the month and year of ingestion, reason for ingestion, health care utilization, and medical outcome. Ingestion frequencies were stratified by age and reason. Data were divided into pre- and postintervention periods for comparative analysis. RESULTS: Unintentional ingestions of OTC cough and cold medications decreased 33.4% and therapeutic errors by 46.0%. Health care facility referral declined for unintentional ingestions (28.9% <2 years of age, 19.9% 2-5 years of age, P < .0001) and therapeutic errors in children younger than 2 years of age (59.2%, P < .0001). Moderate and severe adverse outcomes decreased for unintentional ingestions in children younger than 2 years of age by 32.4% and by 21.3% in 2- to 5-year olds, P < .0001. CONCLUSIONS: The restriction of OTC cough and cold medications has led to a decline in unintentional ingestions, therapeutic errors, health care facility referral, and serious medical outcomes in children younger than 2 years of age. There has also been a decline in ingestions in 2- to 5-year-old children.

Restricting cough and cold medicines in children.

AIMS: Based on concerns about safety and efficacy, international authorities have either advised against the use of cough and cold medication or considering such action. We aimed to systematically review the evidence for the effectiveness and safety of cough and cold medicines in children. METHODS: We conducted a systematic review to identify studies relating to the use of products to treat symptoms of the common cold, influenza or allergic rhinitis, and relating to poisoning or toxicity from unintentional ingestion or overdose in children (<12 years). Medline, Embase and the Cochrane database were searched. No meta-analysis was undertaken because of the paucity of evidence, multiple medicines available, and the need to consider both effectiveness and safety. RESULTS: Seventy two relevant studies or clinical reports were identified. There was little support for the effectiveness of these medicines for acute cough or the common cold in children. However, the majority of these medicines do not appear to be highly toxic in children and are not a major cause of severe effects following unintentional poisoning. The common use of these agents does not appear to be responsible for increased deaths in young children. Many cases of toxicity from cough and cold medications in young children are a result of therapeutic error. Particular medications, including diphenhydramine and codeine, appear to be associated with a high frequency of severe adverse effects and toxicity. CONCLUSION: Restriction of cough and cold medicines in children is supported by currently available evidence.

Risk factors for rhabdomyolysis following doxylamine overdose.

The objective of this prospective study was to identify risk factors for developing rhabdomyolysis in patients with doxylamine overdose. Patients who were admitted to a university teaching hospital between July 2000 and September 2005 due to doxylamine overdose were recruited. Demographic information, clinical variables, and laboratory data were investigated. Twenty-seven (M/F 12/15, age 33.2 +/-13.1 years) patients were enrolled. Sixteen (59%) of 27 patients developed rhabdomyolysis and three (19%) of 16 patients with rhabdomyolysis also developed acute renal failure. Patients who developed rhabdomyolysis differed from those who did not in the amount of doxylamine ingested, initial serum creatitnine and arterial pH. In multivariate regression analysis, the only reliable predictor of rhabdomyolysis was the amount of doxylamine ingested (P = 0.039). The amount of doxylamine ingested (>/= 20 mg/kg) predicted the development of rhabdomyolysis with a sensitivity of 81%, a specificity of 82%, a positive predictive value of 87%, and a negative predictive value of 75%.In conclusion, rhabdomyolysis following doxylamine overdose was common, occurring in 87% of patients who ingested more than 20 mg/kg. The amount of doxylamine ingested was the only reliable predictor for developing rhabdomyolysis following doxylamine overdose.

Parent and caregiver compliance with poison center advice.

BACKGROUND: The purpose of this study was to assess the compliance of parents and caregivers whose children (under 6 years of age) accidentally ingested antihistamines, decongestants, or both. METHODS: We used a prospective-descriptive study design and developed a convenience sample from eligible calls retrieved from the records from January 19, 1999 to February 28, 1999. Poison control specialists categorized the children into two groups: toxic and needing treatment in a hospital or nontoxic and not needing treatment at a hospital. Compliance with Poison Control Center advice was measured by follow-up telephone calls made by a research assistant within 7 days of the initial call. RESULTS: One hundred forty-seven calls were retrieved and followed. One hundred and seven (72.8%) callers had been advised that no treatment was needed. One hundred (93.4%) of these 107 followed Poison Control Centre advice. Forty (27.2%) of the 147 callers were advised to take their child to an emergency department. Thirty-nine (97.5%) of these 40 complied with the advice. There was no statistically significant difference in compliance rates between the two groups (chi2 = 0.306, df = 1, p = 0.58). DISCUSSION AND CONCLUSIONS: In this group of callers, compliance was high. Reasons for noncompliance included caregiver anxiety, specifically the need for a second opinion. Future studies are needed to determine the level of compliance more definitively. Studies should include subjects from other age groups, other exposures, and other types of callers.

Hazards of nonprescription medications.

There are hundreds of nonprescription medications available to the consumer. Among these are a number that have potential for toxicity when taken in overdoses or in combination with other medications. This article addresses the pathophysiology, diagnosis, and treatment of selected over-the-counter medication intoxications including antihistamines, dextromethorphan, sympathomimetics, nutritional supplements, and herbal preparations.