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Spyker DA, Dart RC, Yip L, Reynolds K, Brittain S, Yarema M. Population pharmacokinetic analysis of acetaminophen overdose with immediate release, extended release and modified release formulations. Clin Toxicol (Phila) 2022; 60:1113-1121. [PMID: 36106921 DOI: 10.1080/15563650.2022.2114361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES The introduction of delayed release formulations of acetaminophen (APAP) has created concern about the role of formulation in overdose. We examined the APAP overdose pharmacokinetic (PK) profiles to assess the role of dose, coingestants and formulation: immediate release (IR), extended release (ER), and modified release (MR) on APAP pharmacokinetic measures. METHODS We collected by-subject APAP PK data: subject description, timed blood APAP concentrations, dose, and coingestants. We sought both overdose and randomized controlled trials (RCTs) for supratherapeutic doses involving ER or MR formulations. Data analysis and simulation used the non-linear mixed-effects modeling program NONMEM-version 7.4. RESULTS The final dataset comprised 3,033 [APAP] from 356 subjects and 15 sources including 3 RCTs (179 subjects receiving IR, 122 ER, 65 MR). The final population PK (PopPK) model was a linear 2-compartment model with first-order (oral) absorption. Covariate relationships included: APAP absorption rate and bioavailability decreased with increased oral dose (p < 0.00005) for all 3 formulations (MR > ER > IR). Post hoc analyses showed opioid coingestant increased exposure (area under the curve, AUC) by factor of 1.6. Simulations of 100 g vs 10 g doses for IR, ER and MR showed overdose of the ER formulation exhibits slower absorption and lower Cmax, overall exposure (AUC) is less than 80% of an equivalent dose of IR acetaminophen. The overall exposure for the MR formulation is less than 70% of an equivalent dose of IR. CONCLUSIONS Acetaminophen ER and MR formulations have slower absorption and decreased bioavailability leading to a lower Cmax and later Tmax than the IR formulation. These results have potential clinical implications because delayed absorption could confound use of the Rumack-Matthew nomogram by underestimating the severity of ingestion early in the course of treatment.
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Affiliation(s)
| | | | - Luke Yip
- Rocky Mountain Poison and Drug Center, Denver, CO, USA
| | - Kate Reynolds
- Rocky Mountain Poison and Drug Center, Denver, CO, USA
| | | | - Mark Yarema
- Poison and Drug Information Service, Calgary, Alberta, CA, USA
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Gosselin S, Juurlink DN, Kielstein JT, Ghannoum M, Lavergne V, Nolin TD, Hoffman RS. Extracorporeal treatment for acetaminophen poisoning: recommendations from the EXTRIP workgroup. Clin Toxicol (Phila) 2014; 52:856-67. [PMID: 25133498 DOI: 10.3109/15563650.2014.946994] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup was created to provide evidence-based recommendations on the use of extracorporeal treatments (ECTR) in poisoning and the results are presented here for acetaminophen (APAP). METHODS After a systematic review of the literature, a subgroup selected and reviewed the articles and summarized clinical and toxicokinetic data in order to propose structured voting statements following a pre-determined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements, and the RAND/UCLA Appropriateness Method was used to quantify disagreement. Following discussion, a second vote determined the final recommendations. RESULTS Twenty-four articles (1 randomized controlled trial, 1 observational study, 2 pharmacokinetic studies, and 20 case reports or case series) were identified, yielding an overall very low quality of evidence for all recommendations. Clinical data on 135 patients and toxicokinetic data on 54 patients were analyzed. Twenty-three fatalities were reviewed. The workgroup agreed that N-acetylcysteine (NAC) is the mainstay of treatment, and that ECTR is not warranted in most cases of APAP poisoning. However, given that APAP is dialyzable, the workgroup agreed that ECTR is suggested in patients with excessively large overdoses who display features of mitochondrial dysfunction. This is reflected by early development of altered mental status and severe metabolic acidosis prior to the onset of hepatic failure. Specific recommendations for ECTR include an APAP concentration over 1000 mg/L if NAC is not administered (1D), signs of mitochondrial dysfunction and an APAP concentration over 700 mg/L (4630 mmol/L) if NAC is not administered (1D) and signs of mitochondrial dysfunction and an APAP concentration over 900 mg/L (5960 mmol/L) if NAC is administered (1D). Intermittent hemodialysis (HD) is the preferred ECTR modality in APAP poisoning (1D). CONCLUSION APAP is amenable to extracorporeal removal. Due to the efficacy of NAC, ECTR is reserved for rare situations when the efficacy of NAC has not been definitively demonstrated.
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Affiliation(s)
- S Gosselin
- Department of Emergency Medicine, Medical Toxicology Service, McGill University Health Centre, McGill University , Montréal, QC , Canada
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Sivilotti MLA, Juurlink DN, Garland JS, Lenga I, Poley R, Hanly LN, Thompson M. Antidote removal during haemodialysis for massive acetaminophen overdose. Clin Toxicol (Phila) 2013; 51:855-63. [PMID: 24134534 DOI: 10.3109/15563650.2013.844824] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Haemodialysis is sometimes used for patients with massive acetaminophen overdose when signs of "mitochondrial paralysis" (lactic acidosis, altered mental status, hypothermia and hyperglycaemia) are present. The role of haemodialysis is debated, in part because the evidence base is weak and the endogenous clearance of acetaminophen is high. There is also concern because the antidote acetylcysteine is also dialyzable. We prospectively measured serum acetylcysteine concentrations during haemodialysis in three such cases. CASE DETAILS Three adults each presented comatose and acidemic 10 to ~18 h after ingesting > 1000mg/kg of acetaminophen. Two were hypothermic and hyperglycaemic. Serum lactate concentrations ranged from 7 mM to 12.5 mM. All three were intubated, and initial acetaminophen concentrations were as high as 5980 μM (900 μg/mL). An intravenous loading dose of 150 mg/kg acetylcysteine was initiated between 10.8 and ~18 h post ingestion, and additional doses were empirically administered during haemodialysis to compensate for possible antidote removal. A single run of 3-4 h of haemodialysis removed 10-20 g of acetaminophen (48-80% of remaining body burden), reduced serum acetaminophen concentrations by 56-84% (total clearance 3.4-7.8 mL/kg/min), accelerated native acetaminophen clearance (mean elimination half-life 580 min pre-dialysis, 120 min during and 340 min post-dialysis) and corrected acidemia. Extraction ratios of acetylcysteine across the dialysis circuit ranged from 73% to 87% (dialysance 3.0 to 5.3 mL/kg/min). All three patients recovered fully, and none developed coagulopathy or other signs of liver failure. DISCUSSION When massive acetaminophen ingestion is accompanied by coma and lactic acidosis, emergency haemodialysis can result in rapid biochemical improvement. As expected, haemodialysis more than doubles the clearance of both acetaminophen and acetylcysteine. Because acetylcysteine dosing is largely empirical, we recommend doubling the dose during haemodialysis, with an additional half-load when dialysis exceeds 6 h.
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Affiliation(s)
- M L A Sivilotti
- Department of Emergency Medicine, Queen's University , Kingston, ON , Canada
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Shah AD, Wood DM, Dargan PI. Understanding lactic acidosis in paracetamol (acetaminophen) poisoning. Br J Clin Pharmacol 2011; 71:20-8. [PMID: 21143497 PMCID: PMC3018022 DOI: 10.1111/j.1365-2125.2010.03765.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 07/19/2010] [Indexed: 01/10/2023] Open
Abstract
Paracetamol (acetaminophen) is one of the most commonly taken drugs in overdose in many areas of the world, and the most common cause of acute liver failure in both the UK and USA. Paracetamol poisoning can result in lactic acidosis in two different scenarios. First, early in the course of poisoning and before the onset of hepatotoxicity in patients with massive ingestion; a lactic acidosis is usually associated with coma. Experimental evidence from studies in whole animals, perfused liver slices and cell cultures has shown that the toxic metabolite of paracetamol, N-acetyl-p-benzo-quinone imine, inhibits electron transfer in the mitochondrial respiratory chain and thus inhibits aerobic respiration. This occurs only at very high concentrations of paracetamol, and precedes cellular injury by several hours. The second scenario in which lactic acidosis can occur is later in the course of paracetamol poisoning as a consequence of established liver failure. In these patients lactate is elevated primarily because of reduced hepatic clearance, but in shocked patients there may also be a contribution of peripheral anaerobic respiration because of tissue hypoperfusion. In patients admitted to a liver unit with paracetamol hepatotoxicity, the post-resuscitation arterial lactate concentration has been shown to be a strong predictor of mortality, and is included in the modified King's College criteria for consideration of liver transplantation. We would therefore recommend that post-resuscitation lactate is measured in all patients with a severe paracetamol overdose resulting in either reduced conscious level or hepatic failure.
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Affiliation(s)
- Anoop D Shah
- Clinical Toxicology, Guy's and St Thomas' NHS Foundation Trust, Guy's Hospital, Great Maze Pond, London, UK.
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Bodmer M, Monte AA. "Massive acetaminophen ingestion with early metabolic acidosis and coma: treatment with iv nac and continuous venovenous hemodiafiltration" by Wiegand et al., Clin Toxicol (Phila) 48:156-159. Clin Toxicol (Phila) 2010; 48:961; author reply 961-2. [PMID: 21171858 DOI: 10.3109/15563650.2010.535004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Wiegand TJ, Margaretten M, Olson KR. Massive acetaminophen ingestion with early metabolic acidosis and coma: treatment with IV NAC and continuous venovenous hemodiafiltration. Clin Toxicol (Phila) 2010; 48:156-9. [PMID: 20199132 DOI: 10.3109/15563650903524142] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
CONTEXT We report the extraction of acetaminophen by continuous venovenous hemodiafiltration (CVVHD) during treatment of an acute ingestion of 200 g with a peak recorded serum acetaminophen level of 1,614 mg/L (10,652 micromol/L). CASE DETAILS The patient presented with early onset of coma, metabolic acidosis, and hypotension in the absence of significant hepatic injury. In addition to N-acetylcysteine (NAC) therapy, CVVHD was performed to manage the acid-base disturbance. Flow rate, effluent volume, and serum and effluent drug concentrations were obtained at hourly intervals. During 16 h of CVVHD the acetaminophen level dropped from 1,212 to 247 mg/L. DISCUSSION The average clearance of acetaminophen by CVVHD was 2.53 L/h, with removal of 24 g of acetaminophen over 16 h. As NAC is effective in preventing hepatic injury after acute acetaminophen overdose, the role of dialysis or CVVHD is limited.
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Affiliation(s)
- Timothy J Wiegand
- Department of Medicine and Emergency Medicine, Maine Medical Center and Northern New England Poison Center, 901 Washington Avenue, Portland, ME 04102, USA.
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Tan C, Graudins A. Comparative pharmacokinetics of Panadol Extend and immediate-release paracetamol in a simulated overdose model. Emerg Med Australas 2006; 18:398-403. [PMID: 16842311 DOI: 10.1111/j.1742-6723.2006.00873.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Panadol Extend is a modified-release paracetamol formulation in which each 665 mg tablet contains 69% slow-release and 31% immediate-release paracetamol. There are no data on Panadol Extend pharmacokinetics in overdose. It is unknown whether the paracetamol treatment nomogram can be used to make decisions regarding the toxicity of this product in overdose. OBJECTIVE To compare the pharmacokinetics of Panadol Extend and immediate-release paracetamol (APAP-IR) in simulated overdose model in healthy volunteers. METHODS Cross-over study using a dose of 90 mg/kg ideal body weight of Panadol Extend or APAP-IR in seven healthy volunteers. Serum paracetamol concentrations were measured over 12 h. Maximal paracetamol concentration (Cmax), time to Cmax (Tmax), area under the curve (AUC) and elimination half-life (t(1/2)) were compared. RESULTS Mean paracetamol dose was 73 mg/kg actual body weight. Panadol Extend produced lower Cmax (0.208 mmol/L +/- 0.02 vs 0.48 mmol/L +/- 0.02, P = 0.0001) and AUC(0-12 h) when compared with APAP-IR. Tmax was delayed with Panadol Extend (2.83 h +/- 0.26 vs 0.94 h +/- 0.17, P = 0.0001). Absorption was complete in all subjects by 4 h post ingestion in both study arms. Elimination t(1/2) was 1.69 +/- 0.09 h for APAP-IR and 1.65 +/- 0.13 h for Panadol Extend (not significant). CONCLUSIONS Reductions in Panadol Extend Cmax and AUC(0-12 h) might be related to elimination occurring during the absorption phase. In this model of Panadol Extend moderate overdose, Tmax was significantly delayed. In larger overdoses, time to peak paracetamol levels might be further delayed, because of continuing absorption from the formulation. Therefore, the paracetamol treatment nomogram might not reliably predict hepatotoxicity from Panadol Extend if paracetamol levels are measured too early.
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Affiliation(s)
- Clifford Tan
- Department of Emergency Medicine, Clinical and Experimental Toxicology Unit, Prince of Wales Hospital, Randwick, NSW, Australia
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Abstract
Paracetamol poisoning caused by intentional overdose remains a common cause of morbidity. In this article the mechanism of toxicity and the clinical effects and treatment of poisoning, including specific antidotal therapy, are reviewed. Areas for further research directed at reducing morbidity and mortality from paracetamol poisoning are considered.
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Affiliation(s)
- S H Thomas
- Wolfson Department of Clinical Pharmacology, University of Newcastle upon Tyne, U.K
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Edwards DA, Fish SF, Lamson MJ, Lovejoy FH. Prediction of acetaminophen level from clinical history of overdose using a pharmacokinetic model. Ann Emerg Med 1986; 15:1314-9. [PMID: 3777589 DOI: 10.1016/s0196-0644(86)80618-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A retrospective study was undertaken to determine the accuracy of predicting acetaminophen levels using the pharmacokinetic equation for first-order absorption and elimination of a single oral ingestion, (Formula: see text) Forty-four acute adult acetaminophen overdoses were studied during a 22-month period. Eighty levels drawn from 0 to 16 hours after ingestion were evaluated. To standardize the data, only first levels drawn in patients without prior spontaneous or ipecac-induced vomiting were analyzed (n = 26). Of these 26 levels, eight (31%) were drawn from 0 to two hours after ingestion, eight (31%) from two to four hours, and ten (38%) from four to 16 hours, with correlations of 0.59, 0.85, and 0.98, respectively. To determine the accuracy of predicting four-hour levels, five patients with first levels drawn at four hours, prior to vomiting, were evaluated. Substituting appropriate constants, the condensed equation, Cp4h = (0.59) (mg/kg dose), was used to predict the four-hour level (r = 0.99). Preliminary data suggest the ability to accurately predict four-hour acetaminophen levels from ingestion history alone using pharmacokinetic equations.
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Antipyretic analgesics. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0378-6080(84)80013-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Chaturvedi AK, Rao NG, Hurly MP. Toxicological findings in a multi-drug death involving propoxyphene, caffeine, phenacetin, acetaminophen and salicylate. Forensic Sci Int 1983; 23:255-64. [PMID: 6662443 DOI: 10.1016/0379-0738(83)90154-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The toxicological findings of a multi-drug related fatal poisoning are described here. A 35-year-old Caucasian male found dead on the kitchen floor was a known user of abused drugs and had been taking aspirin alone or in combination with phenacetin and caffeine for the relief of joint pains. The gross examination of the organs at autopsy revealed slight grooving of the uncus and various stages of necrosis in the renal papillae. Histological examination confirmed the gross appearance of pulmonary congestion and edema, cerebral edema and interstitial nephritis of the tubules. Toxicological evaluation of the blood and urine samples disclosed the presence of propoxyphene (51 and 250 mg/l), salicylate (185 and 2750 mg/l), caffeine (16 and 37 mg/l), and phenacetin (9.6 and 20 mg/l). Furthermore, acetaminophen also was present in the plasma (54 mg/l) and urine. A gas liquid chromatographic method for simultaneous analysis of phenacetin and caffeine utilizing a nitrogen phosphorus detector was proposed.
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