Use of ondansetron and other antiemetics in the management of toxic acetaminophen ingestions

Assessing the impact of vomiting episodes on outcome after acetaminophen poisoning

Identifying indices of poor prognosis at first presentation after acetaminophen poisoning is the key to both improving clinical care and determining targets for intervention. This study intended to document the prevalence, clinical characteristics and predictors of vomiting and to investigate the relationship between episodes of vomiting at first hospital presentation and outcome in acetaminophen poisoning. This retrospective cohort study included patients who attended the emergency department and were admitted within 24 hr of acetaminophen ingestion. The study was conducted over a period of 5 years from 1 January 2004 to 31 December 2008. Parametric and non-parametric tests were used to test differences between groups depending on the normality of the data. SPSS 15 was used for data analysis. Data from 291 patients were included. Vomiting was present in 65.3% of patients with acetaminophen poisoning at the time of first presentation. Multiple logistic regression showed that significant risk factors for vomiting were present among patients who reported an ingested dose of acetaminophen ≥10 g (p < 0.001) and a latency time of more than 8 hr (p = 0.030). Overall, an increasing trend in prothrombin time (p = 0.03), serum bilirubin (p < 0.001), serum creatinine (p = 0.005), serum potassium (p < 0.001), length of hospital stay (p < 0.001) and the prevalence of patients who had a serum acetaminophen level above a 'possible toxicity' treatment line (p = 0.001) were associated with an increased number of episodes of vomiting. In conclusion, vomiting was common among patients with acetaminophen poisoning. This study suggests that an increase in episodes of vomiting at first presentation appears to be an important risk marker of subsequent nephrotoxicity and hepatotoxicity.

Acute gastroenteritis: from guidelines to real life

Acute gastroenteritis is a very common disease. It causes significant mortality in developing countries and significant economic burden to developed countries. Viruses are responsible for approximately 70% of episodes of acute gastroenteritis in children and rotavirus is one of the best studied of these viruses. Oral rehydration therapy is as effective as intravenous therapy in treating mild to moderate dehydration in acute gastroenteritis and is strongly recommended as the first line therapy. However, the oral rehydration solution is described as an underused simple solution. Vomiting is one of the main reasons to explain the underuse of oral rehydration therapy. Antiemetics are not routinely recommended in treating acute gastroenteritis, though they are still commonly prescribed. Ondansetron is one of the best studied antiemetics and its role in enhancing the compliance of oral rehydration therapy and decreasing the rate of hospitalization has been proved recently. The guidelines regarding the recommendation on antiemetics have been changed according to the evidence of these recent studies.

Association between gastrointestinal manifestations following acetaminophen poisoning and outcome in 291 acetaminophen poisoning patients

BACKGROUND

Acetaminophen poisoning is a common clinical problem, and early identification of patients with more severe poisoning is key to improving outcomes.

PURPOSES

This study intends to document prevalence, clinical characteristics, and predictors of gastrointestinal (GI) manifestations and to assess the impact of these manifestations on outcome in patients with acetaminophen poisoning.

METHODS

This is a retrospective cohort study of hospital admissions for acute acetaminophen poisoning conducted over a period of 5 years from 1 January 2004 to 31 December 2008. Parametric and non-parametric tests were used to test differences between groups depending on the normality of the data. Statistical Package for Social Sciences (SPSS) 15 was used for data analysis.

RESULTS

Two hundred and ninety-one patients were studied; their mean age was 23.01 +/- 7.4 years and 76.6% had GI manifestations. Multiple logistic regression showed that significant risk factors for GI manifestations were present among patients who reported acetaminophen dose ingested >or=10 g (p < 0.001), and latency time more than 8 hours (p = 0.030). GI manifestations at first admission predicted poorer outcomes in terms of estimated acetaminophen levels to be a possible toxic (p < 0.001), elevated bilirubin levels (p = 0.002), prolonged prothrombin time (PT; p = 0.002), elevated creatinine level (p = 0.028), declination of potassium level (p < 0.001), and prolonged hospital stay (p < 0.001).

CONCLUSIONS

GI manifestations were common among patients with acetaminophen poisoning. This study suggests that the presence of GI manifestations at first presentation appears to be an important risk marker of subsequent hepatotoxicity and nephrotoxicity.

Antiemetics for acute gastroenteritis in children

PURPOSE OF REVIEW

The alleviation of vomiting due to gastroenteritis in children can help promote oral rehydration and prevent medical visits for dehydration.

RECENT FINDINGS

Recent randomized, placebo-controlled trials of newer antiemetics, such as serotonin antagonists like ondansetron, have demonstrated efficacy in relief of vomiting, decreased need for intravenous fluid therapy and hospitalizations, without serious adverse effects.

SUMMARY

The ability to arrest further vomiting and prevent intravenous fluid therapy and hospitalization aids children with vomiting so they may tolerate oral fluids and be discharged from medical care. This can reduce the medical care burdens and enhance patient satisfaction. This new pharmaceutical therapy may change how gastroenteritis is managed as it is studied further.

Clinical policy: critical issues in the management of patients presenting to the emergency department with acetaminophen overdose

This clinical policy focuses on critical issues concerning the management of patients presenting to the emergency department (ED) with acetaminophen overdose. The subcommittee reviewed the medical literature relevant to the questions posed. The critical questions are: 1. What are the indications for N-acetylcysteine (NAC) in the acetaminophen overdose patient with a known time of acute ingestion who can be risk stratified by th Rumack-Matthew nomogram? 2. What are the indications for NAC in the acetaminophen overdose patient who cannot be risk stratified by the Rumack-Matthew nomogram? Recommendations are provided on the basis of the strength of evidence of the literature. Level A recommendations represent patient management principles that reflect a high degree of clinical certainty; Level B recommendations represent patient management principles that reflect moderate clinical certainty; and Level C recommendations represent other patient management strategies that are based on preliminary, inconclusive, or conflicting evidence, or based on committee consensus. This guideline is intended for physicians working in EDs.

Antiemetic use in acetaminophen poisoning: how does the route of N-acetylcysteine administration affect utilization?

INTRODUCTION

We sought to compare antiemetic use after acetaminophen poisoning in patients treated with oral or intravenous (IV) N-acetylcysteine (NAC).

METHODS

Our retrospective chart review identified 20 orally treated patients and 17 IV-treated patients. For both groups, we calculated the total number of antiemetic doses given, their associated cost, and also determined parameters that correlated with antiemetic use.

RESULTS

IV-treated patients received fewer total antiemetic doses than those receiving oral NAC (1.1 0.2 vs. 2.8 0.7; P 0.04). Antiemetic cost correlated with doses received for both groups; however, because the regression lines differed (P 0.02), antiemetic therapy cost was less in IV-treated patients. In addition, serum acetaminophen concentration correlated with total antiemetic doses in oral NAC patients (P 0.002) but not with IV treatment patients (P 0.78).

CONCLUSIONS

Intravenous NAC reduced antiemetic utilization, and it costs less than oral therapy. Furthermore, antiemetic use appeared to be determined by a combination of acetaminophen concentration and NAC administration route.

Clinical policy: critical issues in the management of patients presenting to the emergency department with acetaminophen overdose

This clinical policy focuses on critical issues concerning the management of patients presenting to the emergency department (ED) with acetaminophen overdose. The subcommittee reviewed the medical literature relevant to the questions posed. The critical questions are: 1. What are the indications for N-acetylcysteine (NAC) in the acetaminophen overdose patient with a known time of acute ingestion who can be risk stratified by the Rumack-Matthew nomogram? 2. What are the indications for NAC in the acetaminophen overdose patient who cannot be risk stratified by the Rumack-Matthew nomogram? Recommendations are provided on the basis of the strength of evidence of the literature. Level A recommendations represent patient management principles that reflect a high degree of clinical certainty; Level B recommendations represent patient management principles that reflect moderate clinical certainty; and Level C recommendations represent other patient management strategies that are based on preliminary, inconclusive, or conflicting evidence, or based on committee consensus. This guideline is intended for physicians working in EDs.

A Clinical and Pharmacoeconomic Justification for Intravenous Acetylcysteine

Paracetamol (acetaminophen) poisoning remains the most common exposure reported to US poison information centres and the leading cause of poisoning-related fatalities, despite the availability of an effective antidote, acetylcysteine. Oral acetylcysteine solution has been approved for the management of acetaminophen poisoning in the US for four decades. Until the recent approval of intravenous acetylcysteine in the US, it was necessary to compound the oral solution for intravenous administration. The effectiveness and tolerability of oral and intravenous acetylcysteine for the prevention of hepatotoxicity induced by paracetamol poisoning are well established in the literature. Intravenous acetylcysteine may be preferred over oral administration based on improved tolerability, ease of administration and the shortened course of therapy (20 hours intravenous vs 72 hours oral). The two intravenous acetylcysteine regimens documented in the literature, 48 hours and 20 hours, have similar efficacy when started within 8-10 hours of ingestion. Although there are no legal concerns with continuing the routine compounding of the oral solution to an intravenous product, new standards for pharmacy compounding of sterile preparations set forth by the US Pharmacopoeia highlight that the risk of compounding products for intravenous use must be assessed carefully. Changing the route of administration of a sterile oral solution to an intravenous preparation, when a commercial sterile and pyrogen-free product is available, may not be advisable. The best cost-containment strategies must be used for introduction of the more costly sterile, pyrogen-free intravenous acetylcysteine formulation by hospitals and healthcare systems. The intravenous acetylcysteine product is more cost effective when given for 20 hours than other treatment protocols based on the costs of acetylcysteine and hospitalisation. If used per protocol, the 20-hour intravenous acetylcysteine regimen may decrease hospital length of stay, thereby, offsetting the increased drug cost. Data conflict on the efficacy and administration of intravenous acetylcysteine for off-label uses, such as radiographic contrast media-induced nephropathy prevention and reperfusion in orthotopic liver transplantation. The costs for the intravenous formulation for these indications is significantly higher than use of the oral formulation for oral administration in radiographic contrast media-induced nephropathy prevention and compounded for intravenous use in orthotopic liver transplantation. The oral solution should be retained by healthcare systems for oral and inhalation applications, such as respiratory conditions, oral administration for radiographic contrast media nephropathy prevention, or the use of the 72-hour oral protocol to treat paracetamol poisoning, when the intravenous preparation cannot be used.

S-adenosyl-L-methionine (SAMe) for the treatment of acetaminophen toxicity in a dog

An 8-month-old, spayed female Shetland sheepdog presented 48 hours after ingesting acetaminophen (1 gm/kg body weight). On presentation, the dog was laterally recumbent and hypovolemic. The dog had brown mucous membranes, severe Heinz-body hemolytic anemia, bleeding tendencies, and a red blood cell (RBC) glutathione (GSH) concentration that was 10% of reference values, despite a regenerative erythroid response. Treatment with s-adenosyl-l-methionine (SAMe) as a GSH donor successfully rescued this dog, despite the animal's late presentation after drug ingestion. A loading dose (40 mg/kg body weight) of a stable SAMe salt per os was followed by a maintenance dose (20 mg/kg body weight) sid for 7 days. Additional therapeutic interventions included an intravenous (i.v.) infusion of one unit of packed RBCs (on admission), i.v. fluid support (3 days), and famotidine (7 days) to reduce gastric acidity. Sequential assessment of RBC GSH concentrations and RBC morphology documented response to antidote administration within 72 hours. This case suggests that SAMe may provide a therapeutic option for treatment of acetaminophen toxicosis in dogs capable of retaining an orally administered antidote and maintaining adequate hepatic function for metabolism of SAMe to its thiol substrates.