Unrestricted availability of a plasma paracetamol assay service resulting in an increased number of inappropriate requests

Previously, prior approval from the on-call chemical pathologist was required in our hospital for plasma paracetamol measurements. However, since May 1992, there have been no restrictions on ordering this assay. We have assessed the consequences of this policy change by comparing the number and appropriateness of requests for plasma paracetamol measurements in Chinese patients admitted to our hospital with acute poisoning over two six-month periods (July-December) in 1991 and 1993. Requests were considered appropriate if paracetamol ingestion was suspected or unknown drugs were ingested. The number of patients having plasma paracetamol concentrations assayed increased from 51 in 1991 to 141 in 1993 (176%). The corresponding increase in the number of Chinese patients admitted to two of our eight general wards with poisoning was estimated to be 93%. The proportion of 'appropriate' plasma paracetamol measurements dropped from 55% in 1991 to 21% in 1993. Eight patients had plasma paracetamol concentrations above the recommended treatment line; they were all from the group in whom the requests were appropriate. Three of the 135 patients in the group with 'inappropriate' requests were found to have slightly elevated but far from toxic plasma paracetamol concentrations. Unrestricted availability of plasma paracetamol measurements resulted in an increase in the number of inappropriate requests.

Cholestasis as a liver protective factor in paracetamol acute overdose

1. The effect of paracetamol overdoses on its disposition was investigated in cholestatic rats. 2. Paracetamol plasma concentration and hepatic accumulation decrease about 70-80% in cholestatic rats. 3. Cholestatic rats intoxicated with paracetamol showed less hepatic damage as concluded from biochemical and histological findings. These data are correlated with liver and plasmatic paracetamol. 4. These results indicate a decrease in paracetamol toxicity related to stagnant bile.

Comparison of N-acetylcysteine and methylene blue, alone or in combination, for treatment of acetaminophen toxicosis in cats

Acetaminophen is widely used in human beings for analgesic purposes, but is one of the most frequent causes of poisoning in cats. Acetaminophen-poisoned cats develop methemoglobinemia and sometimes hepatic failure. To determine the benefit of using methylene blue, a treatment for methemoglobinemia, along with N-acetylcysteine (NAC), the recommended treatment for acetaminophen-poisoned cats, groups of 3 male and 3 female cats each were given methylene blue NAC, or both after administration of acetaminophen (120 mg/kg of body weight, PO). Male cats seemed more susceptible than female cats to acetaminophen toxicosis, because 3 males died of hepatic failure (2 cats given acetaminophen/methylene blue and 1 given acetaminophen/NAC/methylene blue). Although NAC alone seemed to elicit the best overall response, methylene blue, alone or in combination with NAC, may be useful in female cats.

Paracetamol poisoning: a case study

Over a 1-year period, 24 patients have been admitted to one intensive therapy unit (ITU) with fulminant hepatic failure secondary to paracetamol poisoning. This article reviews one such case and the subsequent management which led to successful transplantation, concentrating on the clinical and nursing implications of the patient's care.

Compound opioid/paracetamol analgesics: misuse and dependence

Ten cases of individuals with a history of chronic compound opioid/paracetamol misuse are described. Potentially useful indicators of toxicity are suggested.

The temporal profile of increased transaminase levels in patients with acetaminophen-induced liver dysfunction

STUDY OBJECTIVE

It is often taught that acetaminophen-induced liver dysfunction occurs only after a latent period of 24 to 48 hours. This study was designed to evaluate the temporal profile of transaminase levels in patients with acetaminophen-induced hepatotoxicity.

DESIGN

Prospective data collection using standard poison control center data sheets.

PARTICIPANTS

Hospitalized patients with acetaminophen exposure who were reported to the Long Island Poison Control Center between January 1993 and June 1994. Patients who presented within 24 hours of ingestion and in whom increased aspartate aminotransferase (AST) levels developed during hospitalization were included in the data analysis. Patients who presented more than 24 hours after ingestion, who had ingested another potentially hepatotoxic agent, or who had ingested acetaminophen over a period of more than 2 hours were excluded.

RESULTS

Of 1,825 patients with reported acetaminophen exposure, 779 had potentially toxic ingestions and were examined in an emergency department. Of 291 patients with toxic acetaminophen levels who were admitted, 36 (12%) had increased levels of AST at some point during hospitalization. All received oral N-acetylcysteine within 2.5 hours of presentation. In 11 of 19 patients who met all inclusion criteria (58%), AST levels were noted to be increased in the 24 hours after ingestion. The median peak AST level was 422 IU/L (range, 74 to 8,538 IU/L). AST levels peaked within 48 hours in 4 patients (21%) and within 72 hours in 18 patients (95%). Six of eight patients with peak AST levels greater than 1,000 IU/L had increased transaminase levels during the 24 hours after acetaminophen ingestion.

CONCLUSION

Acetaminophen poisoning may cause the serum transaminase level to increase during the 24 hours after ingestion.

Serial measurements of serum Gc-globulin in acetaminophen intoxication

OBJECTIVES

To describe serum Gc-globulin and the extent to which it complexes with monomeric actin in the initial phase of acetaminophen (Paracetamol) intoxication and to relate this to the severity of liver necrosis and the clinical course.

PATIENTS AND METHODS

Serial measurements of Gc-globulin and the proportion of Gc-globulin complexed to G-actin (complex ratio) were made on admission and every 3 h thereafter in eighteen consecutive patients with acetaminophen intoxication. Eight patients developed hepatic encephalopathy (HE) and two died.

RESULTS

On admission, all patients had significantly reduced serum Gc-globulin levels compared with normal individuals (P < 0.0001); patients with HE had significantly lower values than patients without HE (P < 0.001). Gc-globulin levels in the two patients who died did not differ from those in patients who survived hepatic encephalopathy. Fourty-four of 52 serum samples with Gc-globulin levels below 120 mg/l were from patients with encephalopathy (all eight of these patients provided at least three samples). The complex ratio on admission did not differ significantly between patients with and those without HE and fluctuated considerably during the observation period. The peak complex ratio was, however, higher in patients with HE than in patients without HE (P < 0.01), and three of four patients with peak complex ratios above 75% had HE. In addition, the mean complex ratio was greater in the two patients who died than in those who survived HE (P < 0.05).

CONCLUSION

Gc-globulin levels were decreased in individuals suffering from acetaminophen intoxication; this decrease correlated with the most severe sign of liver dysfunction, HE. Serum Gc-globulin levels below 120 mg/l and peak complex ratios above 75% may be critical values. However, as a result of considerable fluctuations in the complex ratio, serial measurements are needed to evaluate the Gc-globulin complexing capacity.

Acute renal failure due to acetaminophen ingestion: a case report and review of the literature

Acetaminophen is the most commonly reported drug overdose in the United States. Acute renal failure occurs in less than 2% of all acetaminophen poisonings and 10% of severely poisoned patients. At the therapeutic dosages, acetaminophen can be toxic to the kidneys in patients who are glutathione depleted (chronic alcohol ingestion, starvation, or fasting) or who take drugs that stimulate the P-450 microsomal oxidase enzymes (anticonvulsants). Acute renal failure due to acetaminophen manifests as acute tubular necrosis (ATN). ATN can occur alone or in combination with hepatic necrosis. The azotemia of acetaminophen toxicity is typically reversible, although it may worsen over 7 to 10 days before the recovery of renal function occurs. In severe overdoses, renal failure coincides with hepatic encephalopathy and dialysis may be required. Recognition of acetaminophen nephropathy requires the following: (1) a thorough drug history, including over-the-counter medications such as Tylenol or Nyquil; (2) knowledge of the risk factors that lessen its margin of safety at therapeutic ingestions, i.e., alcoholism; and (3) consideration of acetaminophen in the differential diagnosis of patients who present with combined hepatic dysfunction and ATN.

[Acute liver failure caused by paracetamol: should treatment with N-acetylcysteine be prolonged?]

BACKGROUND

Some cases of paracetamol-induced acute hepatic failure may require liver transplantation but the present shortage of graft urges the search for an alternate therapeutic approach.

CASE REPORT

A 17 year-old girl was admitted for sleepingness and vomiting after about 15 hours of voluntary but denied absorption of paracetamol. Plasma paracetamol concentration was 120 mg/l; factors VII+X level were 55% and factor V 106%. The patient was given IV N-acetylcysteine, 150 mg/kg/30 min, then 50 mg/kg/4 hours. Further decrease in facteur VII level led to pursue administration of N-acetylcysteine (total dose: 350 mg/kg/2 hours). While indication of liver transplantation was considered, clinical and laboratory findings definitely improved.

CONCLUSIONS

N-acetylcysteine may be effective even if administered late. Repeated determination of factor VII could be a good means for managing such a severe condition.

[Paracetamol poisoning--case report]

A case of paracetamol poisoning in 17-month-old girl is presented. Clinical features and therapeutic procedures are described. Differences in paracetamol metabolism between children and adults are compared. Differences in the incidence of paracetamol poisoning between Croatia and USA are surveyed. The role of a physician in the education of parents and medical stuff on paracetamol toxicity is emphasized.

Paracetamol intoxication and N-acetyl-cysteine treatment

N-acetylcysteine is a good and reasonable specific antidotum in case of paracetamol intoxication. It is very active when administered within eight hours after intoxication. It can be used as well as in intravenous as peroral administration. There are few side effects.