Acetylcysteine for acetaminophen overdose in patients who weigh >100 kg.

N-Acetylcysteine (NAC) dosing for acetaminophen (APAP) overdose is weight based (150 mg/kg intravenous or 140-mg/kg oral loading dose) and, in the United States, the dosing protocol recommends using a maximum patient weight of 100 and 110 kg, respectively. Little clinical data describe the use of NAC for APAP poisoning in patients weighing >100 kg. The aim of this study was to describe the demographics, outcomes, and adverse event (AE) rates of patients weighing >100 kg treated with oral or IV NAC for APAP poisoning. Patients were identified from a multicenter retrospective NAC safety study for APAP overdose. We included patients with a recorded weight. Trained chart abstractors used a standardized form. Selected data included age, gender, weight, serum alanine transaminase, and aspartate transaminases, coingestants, NAC administration route, ingestion type, AEs, and outcome [hepatotoxicity (alanine transaminase > 1000 U/L), liver transplant, or death]. Descriptive statistics were used. Of 503 study patients, 37 (7.4%) had recorded weights >100 kg. The median (range) weight was 110 kg (101-160). The median (range) dosing for patients treated with oral NAC was 140 mg/kg (127-143 mg/kg) and 150 (108-168) mg/kg for IV NAC. Hepatotoxicity occurred in 12/36 (33.3%) patients. Death occurred in 4/36 (11.1%) patients. Thirteen NAC-related AEs occurred in 8 patients (1.6 per person). All AEs were related to NAC and were rated nonserious by the reviewer. Clinicians use an actual weight-based NAC dose rather than a maximum weight cutoff dose. Hepatotoxicity was common in our cohort. AEs were relatively common but not serious.

Safety of non-therapeutic levetiracetam ingestions--a poison center based study.

BACKGROUND: Very limited data is available regarding the safety of levetiracetam in cases of unintentional or intentional ingestions. METHODS: All cases of single agent ingestions of levetiracetam, excluding adverse drug reactions (ADRs), reported to 61 American poison control centers during 2000-2009 were identified. Demographics, dose, symptoms, and medical outcome were abstracted from each case record. RESULTS: A total of 222 cases of single agent levetiracetam ingestions were reported during the study period. Median age was 14.0 years (IQR: 2.0 years, 39.0 years) and 51.8% were female. In 207 of 222 cases (93.2%) medical outcome was known. No deaths were reported and only 1 (0.5%) case resulted in a major outcome and 3 (1.4%) cases resulted in moderate outcomes. Minor, minimal, or no effects were reported in 198 (89.2%) cases. In 27 (12.2%) cases, ingestion was intentional and in 192 (86.5%) unintentional. There were no major outcomes and only one case (1.4%) of moderate outcome in 74 children aged 6 years or less. All ingestions in these children were unintentional. CONCLUSIONS: In this study with a limited number of cases, intentional and unintentional ingestions of levetiracetam were safe in the majority of cases.

Short-term outcomes after Fab antivenom therapy for severe crotaline snakebite.

STUDY OBJECTIVES: We seek to determine the short-term outcomes associated with the use of Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) therapy for severe crotaline snake envenomation and to better define the incidence of hypersensitivity reactions associated with FabAV use. METHODS: We conducted a multicenter observational case series study of patients who received FabAV at 17 US hospitals in 2002 to 2004. A 7-point score incorporating local, systemic, and hematologic venom effects was used to grade envenomation severity before and after FabAV therapy. The primary outcome for response to therapy was the change in overall envenomation severity after FabAV administration. The primary safety outcomes were the rates of immediate hypersensitivity reactions and serum sickness. RESULTS: The outcome-evaluable population included 209 patients, of whom 28 had severe envenomation. All severely envenomated patients improved after receiving FabAV. The median severity scores of severely envenomated patients were 5 (interquartile range [IQR] 5 to 5) before FabAV, 1 (IQR 1 to 2) at the last FabAV loading dose, and 1 (IQR 0 to 1) at the last clinical observation. The proportion of patients with progressive pain, progressive swelling, cardiovascular effects, respiratory effects, neurologic effects, gastrointestinal effects, coagulopathy, and thrombocytopenia all improved after FabAV therapy. The safety population included 247 patients. Immediate hypersensitivity reactions were reported in 6.1% (95% confidence interval 3.4% to 9.8%) of patients. Serum sickness was reported in 5% (95% confidence interval 0.6% to 17%) of patients with a minimum of 6 days of follow-up after the last dose of FabAV. CONCLUSION: FabAV therapy is associated with clinical improvement in severe crotaline snake envenomation. Immediate hypersensitivity and serum sickness rates may be less than described in the FabAV prescribing information.

Factors associated with difficulty achieving initial control with crotalidae polyvalent immune fab antivenom in snakebite patients.

BACKGROUND: The prescribing information for Crotalidae Fab antivenom (FabAV) instructs clinicians to administer FabAV until initial control of the envenomation syndrome is achieved. Risk factors for difficulty achieving initial control are not known. OBJECTIVES: The study aim was to identify factors present before administration of antivenom associated with difficulty achieving initial control. METHODS: The authors conducted a retrospective study of all patients presenting to any one of 17 centers and receiving FabAV from 2002 to 2004. Demographic and historical information, as well as data about nine specific venom effects, were collected prior to the administration of antivenom. An expert panel used standard criteria to determine if initial control was achieved. The patient group that had difficulty achieving initial control was compared to the group that achieved initial control, and adjusted odds ratios were calculated using stepwise logistic regression. RESULTS: A total of 247 patients were included in the final analysis. The majority of patients were envenomated on the upper extremity and were young males. A total of 203 patients (82.2%) achieved initial control. In univariate analysis, thrombocytopenia, bleeding, neurologic effects, and a severe bite were significantly associated with difficulty achieving initial control. After logistic regression, the presence of neurologic effects and thrombocytopenia remained significantly associated with difficulty achieving initial control. When both factors were present, the patient was 13.8 times more likely to have difficulty achieving initial control. CONCLUSIONS: A number of factors were present before the administration of FabAV that were independently associated with difficulty achieving initial control of the envenomation syndrome. Predicting which patients will have difficulty achieving initial control has important ramifications for patient disposition and may provide insight into the mechanisms for lack of antivenom efficacy.

A multicenter comparison of the safety of oral versus intravenous acetylcysteine for treatment of acetaminophen overdose.

UNLABELLED: Oral and intravenous (IV) N-acetylcysteine (NAC) are used for the treatment of acetaminophen poisoning. The objective of this multicenter study was to compare the safety of these two routes of administration. METHODS: We conducted a multicenter chart review of all patients treated with NAC for acetaminophen poisoning. The primary safety outcome was the percentage of patients with NAC-related adverse events. RESULTS: A total of 503 subjects were included in the safety analysis (306 IV-only, 145 oral-only, and 52 both routes). There were no serious adverse events related to NAC for either route. Nausea and vomiting were the most common related adverse events and were more common with oral treatment (23 vs. 9%). Anaphylactoid reactions were more common with IV administration (6 vs. 2%). CONCLUSIONS: IV and oral NAC are generally mild adverse drug reactions.

Crotaline Fab antivenom appears to be effective in cases of severe North American pit viper envenomation: an integrative review.

BACKGROUND: In 2000, the United States Food and Drug Administration approved Crotalidae Polyvalent Immune Fab (Ovine) (hereafter, FabAV), "for the management of patients with minimal to moderate North American Crotalid envenomation." Because whole-IgG pit viper antivenom is no longer available in the United States, FabAV is currently the only specific treatment option available to United States clinicians treating snakebite victims of any severity. No clinical trial data are available concerning the effectiveness of FabAV for treatment of severe snakebite, but several published articles describe its use in this setting. METHODS: We performed a comprehensive review of the English-language medical literature to identify all publications (1996 to July, 2008) containing data about the administration of FabAV. Two trained reviewers separately extracted case-level data concerning the administration of FabAV to patients with severe envenomation by North American crotaline snakes to a standardized form. Descriptive statistics were used. In addition, we hand-searched the US National Poison Data System reports for the years 2000-2006 to identify and describe any reports of death that occurred after FabAV administration. RESULTS: The literature review found 147 unique publications regarding FabAV. Twenty-four evaluable cases of severe human envenomation treated with FabAV were identified in 19 publications. Seven cases were described in five cohort studies, and 17 cases were described in 14 single patient case reports or non-cohort case series. Sixty-five specific severe venom effects were reported in these 24 patients, of which 50 effects (77%) improved or resolved after FabAV therapy. Initial control of all severe venom effects was achieved in 12 patients (50%). The rate at which initial control was achieved was significantly higher among patients reported in the cohort series than in the case series and non-cohort reports (100% vs. 29%, P = 0.005). The median dose of FabAV used to obtain initial control was 6 vials (range: 4 - 18 vials). Nine patients had severe venom effects that persisted despite FabAV therapy. Recurrent and/or delayed-onset severe defibrination syndrome occurred in 12 patients, most of whom did not receive recommended maintenance FabAV dosing. No patient developed systemic bleeding. CONCLUSION: In this structured literature review, FabAV appears to be effective in the management of severe crotaline snake envenomation. Incomplete response to therapy, recurrence of venom effects, and delayed-onset venom effects were reported in case reports, but not reported in cohort studies.