Effectiveness of delayed activated charcoal administration in simulated paracetamol (acetaminophen) overdose. A prospective evaluation of the effect of activated charcoal before oral N-acetylcysteine in acetaminophen overdose. Activated charcoal reduces the need for N-acetylcysteine treatment after acetaminophen (paracetamol) overdose. A comparison of the efficacy of gastric lavage, ipecacuanha and activated charcoal in the emergency management of paracetamol overdose. Treating paracetamol overdose by charcoal haemoperfusion and long-hours high-flux dialysis. Comparative antidotal efficacy of activated charcoal tablets, capsules and suspension in healthy volunteers. [Evaluation of the efficacy of N-acetylcysteine administered alone or in combination with activated charcoal in the treatment of acetaminophen overdoses]. Improved outcome of paracetamol-induced fulminant hepatic failure by late administration of acetylcysteine. Intravenous acetylcysteine in paracetamol induced fulminant hepatic failure: a prospective controlled trial.
Oral activated charcoal is used to treat drug overdose and is effective at reducing drug absorption when administered within 1 h of drug ingestion. There are fewer data on efficacy when the delay is longer, as is the case in most drug overdoses. This study investigated the efficacy of activated charcoal at preventing paracetamol (acetaminophen) absorption after simulated overdose when administration was delayed between 1 and 4 h.
                An open randomized-order four-way crossover study was performed in healthy volunteers comparing the effect of activated charcoal 50 g on the absorption of 3 g paracetamol tablets when administered after an interval of 1, 2 or 4 h or not at all. Plasma paracetamol concentrations were measured over 9 h after paracetamol ingestion using h.p.l.c. and areas under the curve between 4 and 9 h (AUC(4,9 h)) calculated as a measure of paracetamol absorption.
                Activated charcoal significantly reduced paracetamol AUC(4,9 h) when administered after 1 h (mean reduction 56%; 95% Confidence intervals 34, 78; P<0.002) or 2 h (22%; 6, 39; P<0.03) but not after 4 h (8%; -8, 24). When administered after 1 h activated charcoal reduced individual plasma paracetamol concentrations significantly at all times between 4 and 9 h after paracetamol administration. Administration at 2 or 4 h had no significant effect.
                These results in healthy volunteers cannot be extrapolated directly to poisoned patients. However, they provide no evidence of efficacy for activated charcoal when administered after an interval of more than 2 h. To evaluate whether activated charcoal (AC) reduces the efficacy of subsequent oral N-acetylcysteine therapy during acute acetaminophen overdose.
                Prospective observational case series of all acute acetaminophen overdoses reported to three certified regional poison centers. TYPES OF PATIENTS: All patients with acute acetaminophen overdose in whom N-acetylcysteine therapy was initiated within 16 hours after ingestion.
                All patients were treated with oral N-acetylcysteine therapy for 72 hours. The decision to use AC was left to the treating physician without input from the investigator.
                One hundred twenty-two patients were evaluated. Maximum recorded SGOT levels of more than 125 U/mL were defined as evidence of hepatotoxicity. AC was used in addition to N-acetylcysteine in 82 of 122 patients. Hepatotoxicity developed in four of 82 patients who received AC versus ten of 40 patients who did not receive AC (P < .005). An increasing dose of N-acetylcysteine provided no additional benefit (P > .05). Spacing the administration of AC and oral N-acetylcysteine less than or more than two hours apart did not affect outcome (P > .05).
                Administration of AC before the administration of oral N-acetylcysteine in acetaminophen overdose does not reduce the efficacy of N-acetylcysteine therapy and may provide some additional hepatoprotective benefit. The practice of increasing the dose of oral N-acetylcysteine therapy after the administration of AC appears unwarranted. The evidence for efficacy of gastric lavage and activated charcoal for gastrointestinal decontamination in poisoning has relied entirely on volunteer studies and/or pharmacokinetic studies and evidence for any clinical benefits or resource savings is lacking.
                To investigate the value of gastrointestinal decontamination using gastric lavage and/or activated charcoal in acetaminophen (paracetamol) poisoning.
                We analyzed a series of 981 consecutive acetaminophen poisonings. These patients were treated with gastric lavage and activated charcoal, activated charcoal alone, or no gastrointestinal decontamination. The decision as to which treatment was received was determined by patient cooperation, the treating physician, coingested drugs, and time to presentation after the overdose.
                Of 981 patients admitted over 10 years, 10% (100) had serum concentrations of acetaminophen that indicated a probable or high risk of hepatotoxicity. The risk of toxic concentrations for patients ingesting less than 10 g of acetaminophen was very low. In patients presenting within 24 hours, who had ingested 10 g or more, those who had been given activated charcoal were significantly less likely to have probable or high risk concentrations (Odds ratio 0.36, 95% CI 0.23-0.58, p < 0.0001). Gastric lavage, in addition to activated charcoal, did not further decrease the risk (Odds ratio 1.12, 95% CI 0.57-2.20, p = 0.86).
                Toxic concentrations of serum acetaminophen (paracetamol) are uncommon in patients ingesting less than 10 g. In those ingesting more, activated charcoal appears to reduce the number of patients who achieve toxic acetaminophen concentrations and thus may reduce the need for treatment and hospital stay. The aim of this prospective trial was to compare the efficacy of gastric lavage, activated charcoal and ipecacuanha at limiting the absorption of paracetamol in overdose and to assess the significance of the continued absorption of paracetamol following treatment. Patients aged 16 and over who had ingested 5 gms or more of paracetamol within 4h of admission were entered into the trial. The percentage fall in plasma paracetamol level was used as the measure of the success of a treatment at limiting absorption. The mean percentage fall was 39.3 for gastric lavage, 52.2 for activated charcoal and 40.7 for ipecacuanha, with a significant difference between the treatment methods (p = 0.03). Activated charcoal was more effective at limiting the absorption of paracetamol following overdose than either gastric lavage or ipecacuanha induced emesis. In treated patients continuing paracetamol absorption is not significant if more than 2h have elapsed since ingestion. After serious paracetamol overdose, charcoal haemoperfusion was used to remove paracetamol from the circulation, aiming to reduce the severity of subsequent hepatic damage. Daily long-hours high-flux dialysis was given to patients with grade III-IV hepatic encephalopathy, and also to those at risk of developing encephalopathy. We reviewed patients treated in this manner who had not received N-acetylcysteine within the first 15 h after overdose. From January 1983 to January 1993, 73 patients with serious paracetamol overdose were seen, of whom 51 received charcoal haemoperfusion and/or high-flux dialysis. Patients who were admitted within the first 42 h after overdose and who received haemoperfusion and/or dialysis had significantly lower peak levels of prothrombin time, bilirubin and creatinine than those who were admitted after 42 h. Mortality was also lower amongst patients admitted before 42 h, at 2/18 (11%) vs. 15/33 (45%), p < 0.05. The efficacy of several formulations of activated charcoal (AC) was compared by measuring the intestinal absorption of a solution of 1 g paracetamol administered 2 min before administration of 5 g AC as suspension (200 ml), tablets (40 of 125 mg) or capsules (25 of 200 mg). The suspension medium without AC was used as the control treatment. Based on the results of a pilot experiment, an 8 subject panel was used in a two 4 x 4 Latin square design. All treatments with AC resulted in a statistically significant decrease in paracetamol absorption compared to the control treatment. The suspension was considerably and significantly more effective than the tablets or capsules. Treatment with tablets was slightly but significantly more effective than capsules. The intake of large numbers of tablets and capsules was difficult. In the hospital AC suspensions are available. For first aid elsewhere, at home, at the working place or in the general practitioner's surgery a preservable and easily redispersible AC formulation would be preferable to the present solid forms. To evaluate the efficacy of N-acetylcysteine (N-AC) alone or combined with multiple-dose activated charcoal (AC) in the treatment of acetaminophen (ACT) overdose.
                Prospective observational case series of 14 consecutive pediatric patients. Group A (n = 7) were treated only with N-AC and group B (n = 7) with N-AC combined with AC. Plasma ACT concentrations were measured at 0.0, 24 and 48 h. As a measure of ACT disappearance, half-life of elimination (t1/2 beta) and exogenous body clearance (ClB) were calculated.
                Group A, Initial and final mean ACT plasmatic levels were 27 micrograms/mL and 4 micrograms/mL; t1/2 beta of 17 h and ClB 0.640 mL.kg.min. Group B, 27 micrograms/mL and 0.66 microgram/mL; t1/2 beta of 10 h and ClB 1.092 mL.kg.min. For both t1/2 beta and ClB differences, p < 0.05 (SS).
                N-AC significantly decreased the plasma ACT levels in both treatments; however, there were several advantages with the combined therapy: AC enhanced the efficacy of N-AC according with the higher eliminatión of the overdosed drug (97.6% vs. 85.2%), the t1/2 beta decreased 42%, and the ClB increased 70% in relation to the group A. Data of this study suggested that N-AC plus AC is more effective than N-AC alone in enhancing ACT elimination in overdosed patients and that it provided additional hepatoprotective benefit. The influence of acetylcysteine, administered at presentation to hospital, on the subsequent clinical course of 100 patients who developed paracetamol-induced fulminant hepatic failure was analysed retrospectively. Mortality was 37% in patients who received acetylcysteine 10-36 h after the overdose, compared with 58% in patients not given the antidote. In patients given acetylcysteine, progression to grade III/IV coma was significantly less common than in those who did not receive the antidote (51% vs 75%), although the median peak prothrombin time was similar for both groups. Whether the beneficial effect is related to replenishment of glutathione stores or a consequence of another hepatic protective mechanism of acetylcysteine requires further study. To see whether intravenous acetylcysteine would improve outcome in patients with fulminant hepatic failure after paracetamol overdose.
                A prospective randomised controlled study.
                The Institute of Liver Studies, King's College Hospital, London.
                50 consecutive patients (21 male) aged 16-60 with fulminant hepatic failure after paracetamol overdose who had not previously received acetylcysteine.
                Conventional intensive liver care plus either acetylcysteine (25 patients) in the same dose regimen as used early after a paracetamol overdose, except that the infusion was continued until recovery from encephalopathy or death, or an equivalent volume of 5% dextrose (25 patients).
                Survival; incidence of cerebral oedema, renal failure, and hypotension requiring inotropic support; liver function as assessed by prolongation of the prothrombin time; and degree of encephalopathy.
                The rate of survival was significantly higher in the acetylcysteine treated group than in the controls (48% (12/25 patients) v 20% (5/25); p = 0.037, 95% confidence interval for difference in proportions surviving 3% to 53%). Acetylcysteine treated patients had a lower incidence of cerebral oedema (40% (10/25) v 68% (17/25); p = 0.047, 95% confidence interval for difference in incidence 2% to 54%), and fewer developed hypotension requiring inotropic support (48% (12/25) v 80% (20/25); p = 0.018, 95% confidence interval 7% to 57%). Rates of deterioration and recovery of liver function, however, were similar in the two groups. No adverse reactions to acetylcysteine were seen.
                Acetylcysteine is safe and effective in fulminant hepatic failure after paracetamol overdose.
Our results highlight a paucity of randomised trials on interventions for paracetamol overdose. Activated charcoal seems the best choice to reduce absorption. N-acetylcysteine should be given to patients with overdose but the selection criteria are not clear. No N-acetylcysteine regime has been shown to be more effective than any other. It is a delicate balance when to proceed to liver transplantation, which may be life-saving for patients with poor prognosis.