Impact of Restricting Paracetamol Pack Sizes on Paracetamol Poisoning in the United Kingdom

Emergency department visits for overdoses of acetaminophen-containing products

BACKGROUND

Limited national data on the circumstances of acetaminophen overdoses have hindered identification and implementation of prevention strategies.

PURPOSE

To estimate the frequency of and characterize risks for emergency department visits for acetaminophen overdoses that were not related to abuse in the U.S.

METHODS

Data were collected from two components of the National Electronic Injury Surveillance System from January 1, 2006, through December 31, 2007, and analyzed from 2009 to 2010 to estimate the annual number of emergency department visits for non-abuse-related acetaminophen overdose by patient demographics, treatments, and type and amount of acetaminophen-containing product ingested.

RESULTS

There were an estimated 78,414 emergency department visits (95% CI=63655, 93172) annually for non-abuse-related overdoses of acetaminophen-containing products. Most emergency department visits for acetaminophen overdose were for self-directed violence (69.8%, 95% CI=66.4%, 73.2%), with the highest rate among patients aged 15-24 years (46.4 per 100,000 individuals per year). Unsupervised ingestions by children aged <6 years accounted for 13.4% (95% CI=11.0%, 15.9%) of visits for acetaminophen overdoses (42.5 per 100,000 individuals per year). Therapeutic misadventures accounted for 16.7% (95% CI=14.0%, 19.5%) of visits and most involved overuse for medicinal effects (56.1%, 95% CI=50.6%, 61.6%) rather than use of multiple acetaminophen-containing products or dose confusion.

CONCLUSIONS

Non-abuse-related overdoses of acetaminophen products lead to many emergency department visits each year, particularly emergency department visits for self-directed violence. Acetaminophen overdose prevention efforts will likely need to be multidimensional.

Predicting and preventing acute drug-induced liver injury: what's new in 2010?

IMPORTANCE OF THE FIELD

The field of drug-induced liver injury (DILI) continues to expand in terms of global registries and with new agents added every year. Given the need to improve on our current methods of preclinical testing and monitoring for DILI during both clinical trials and in the post-approval setting, there is increasing research aimed at better understanding why injury occurs and who is most susceptible. To this end, the active pursuit of biomarkers that will predict injury prior to its occurrence and genetic testing that can identify individuals at risk of DILI continue to be at the forefront.

AREAS COVERED IN THIS REVIEW

While alanine aminotransferase (ALT) testing remains the workhorse of biochemical monitoring, it only detects hepatic injury after it has occurred and, therefore, is not a true predictor. The utility and shortcomings of ALT and other liver tests are reviewed along with a synopsis of several other candidate biomarkers that are being studied. In addition, we review the recent data supporting testing for genetic predisposition to DILI and how identifying clinical risk factors may translate into better means for preventing DILI.

WHAT THE READER WILL GAIN

We update the basis on which age and gender are considered risk factors for DILI, and review the latest reports detailing the association of several candidate genes and the development of DILI in a susceptible patient. Human leukocyte antigen-B*5701 is closely linked to the hypersensitivity reaction seen with abacavir, and such screening has been successfully incorporated into HIV treatment around the globe and offers the promise that testing for other genetic markers will soon become a routine part of clinical practice. At present, candidate genes conferring specific susceptibility to DILI have been identified for a relatively few agents (e.g., flucloxacillin, amoxicillin-clavulanate, ximelagatran and isoniazid), but many more are under study. Preventing DILI often comes down to avoiding the use of potentially hepatotoxic drugs in certain situations, and we review the clinical scenarios in which this is most relevant.

TAKE HOME MESSAGE

Given the number and range of studies aimed at identifying predictors of DILI, the focus of this review is to summarize what we consider to be the most relevant new information published on the topics of clinical and genetic factors that predispose to DILI, the use of biomarkers as predictors of acute DILI, along with advances in prevention strategies.

Paracetamol (acetaminophen) with or without an antiemetic for acute migraine headaches in adults

BACKGROUND

Migraine is a common, disabling condition and a burden for the individual, health services and society. Many sufferers choose not to, or are unable to, seek professional help and rely on over-the-counter analgesics. Co-therapy with an antiemetic should help to reduce nausea and vomiting commonly associated with migraine.

OBJECTIVES

To determine the efficacy and tolerability of paracetamol (acetaminophen), alone or in combination with an antiemetic, compared to placebo and other active interventions in the treatment of acute migraine in adults.

SEARCH STRATEGY

We searched Cochrane CENTRAL, MEDLINE, EMBASE and the Oxford Pain Relief Database for studies through 4 October 2010.

SELECTION CRITERIA

We included randomised, double-blind, placebo- or active-controlled studies using self-administered paracetamol to treat a migraine headache episode, with at least 10 participants per treatment arm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Numbers of participants achieving each outcome were used to calculate relative risk and numbers needed to treat (NNT) or harm (NNH) compared to placebo or other active treatment.

MAIN RESULTS

Ten studies (2769 participants, 4062 attacks) compared paracetamol 1000 mg, alone or in combination with an antiemetic, with placebo or other active comparators, mainly sumatriptan 100 mg. For all efficacy outcomes paracetamol was superior to placebo, with NNTs of 12, 5.2 and 5.0 for 2-hour pain-free and 1- and 2-hour headache relief, respectively, when medication was taken for moderate to severe pain. Nausea, photophobia and phonophobia were reduced more with paracetamol than with placebo at 2 hours (NNTs of 7 to 11); more individuals were free of any functional disability at 2 hours with paracetamol (NNT 10); and fewer participants needed rescue medication over 6 hours (NNT 6).Paracetamol 1000 mg plus metoclopramide 10 mg was not significantly different from oral sumatriptan 100 mg for 2-hour headache relief; there were no 2-hour pain-free data. There was no significant difference between the paracetamol plus metoclopramide combination and sumatriptan for relief of "light/noise sensitivity" at 2 hours, but slightly more individuals needed rescue medication over 24 hours with the combination therapy (NNT 17).Adverse event rates were similar between paracetamol and placebo, and between paracetamol plus metoclopramide and sumatriptan. No serious adverse events occurred with paracetamol alone, but more "major" adverse events occurred with sumatriptan than with the combination therapy (NNH 32).

AUTHORS' CONCLUSIONS

Paracetamol 1000 mg alone is an effective treatment for acute migraine headaches, and the addition of 10 mg metoclopramide gives short-term efficacy equivalent to oral sumatriptan 100 mg. Adverse events with paracetamol did not differ from placebo; "major" adverse events were slightly more common with sumatriptan than with paracetamol plus metoclopramide.

New marker for paracetamol poisoning-revolution or evolution?

There is a pressing need for new biomarkers that can improve the care of patients with paracetamol poisoning, a common clinical problem. In this issue of Clinical Toxicology a new marker is proposed that has a number of attractive properties. This commentary discusses the use of biomarkers in the context of the management of paracetamol-induced liver injury. New biomarkers should allow better triage and management of & "at risk" patients.

Suicide survey in a London borough: primary care and public health perspectives

BACKGROUND

In order to achieve the national target of 20% reduction in suicide in the UK, many primary care trusts have developed local suicide prevention action plans. However, there is concern about a lack of a whole-system approach in some localities. Suicide surveys are a necessary component of any suicide reduction strategy.

METHODS

All deaths by suicides and open verdicts of a multi-ethnic, socio-economically diverse London Borough's residents between February 2005 and February 2008 were identified (n = 54). Health records of the identified subjects were analysed by two researchers.

RESULTS

The annual rate of suicide in the study period was 6.8 per 100 000 inhabitants. Of the 54 cases of suicide in the study period, 45% had a psychiatric diagnosis and 18% were in current contact with mental health services. Hanging was the most frequent mode of suicide. Twenty-four per cent were not registered with a GP, most of whom were immigrants. Twenty-five per cent had seen their GP within a month of suicide. The rate of suicide in those born in Ireland was 17.7 per 100 000.

CONCLUSIONS

Suicide survey is a feasible method of monitoring suicide, sharing data between key stakeholders and learning from the trends uncovered.

The epidemiology of childhood poisonings in Cyprus

Information on childhood poisonings in Cyprus is limited. Our objective was to examine the epidemiology of poisonings among children in Cyprus. All children up to 15 years of age admitted for poisoning to the Archbishop Makarios Hospital in Nicosia, Cyprus between 2005 and 2008 were included in our study. All hospital poisoning records were reviewed. A total of 257 children were admitted for poisoning. The mean age of children was 3.1 years, of which 83.7% were below the age of 5 years old, while 53% were boys. The poisoning hospitalizations accounted for about 3% of all admissions to the pediatric department during the study period (4 years). The annual cumulative incidence of childhood poisoning hospitalizations was 116 per 100,000 children. Medications accounted for 46.1% of all poisonings, the most frequent cause being paracetamol (9.8%), cardiovascular medications (5.3%), antitussive medications (4.5%), and other painkillers (4.1%). Another 37.6% of hospitalizations involved household products such as household cleaning products (11.8%), petroleum products (11.0%), and rodenticides (5.7%). Among children who ingested petroleum distillates, 55.6% developed clinical symptomatology. The vast majority of cases were accidental (93.8%). Suicidal cases involved children 8-14 years old, mainly girls, and the most frequent poisoning ingested was paracetamol (46.7%). Poisoning hospitalizations represent an important cause of morbidity among children in Cyprus. Preventive strategies should include the education of caregivers on the handling of medications and household products as well as legislation requiring child-resistant packaging for all medications and household products including petroleum distillates.

Caffeine fatalities--do sales restrictions prevent intentional intoxications?

OBJECTIVE

Caffeine is widely available in beverages and in different over-the-counter products, including tablets containing 100 mg caffeine. Because intentional fatal intoxications with caffeine occur, the maximum quantity of caffeine tablets that can be bought over the counter in a single purchase was restricted from 250 to 30 in Sweden in the year 2004. The objective of this article was to study the effect of this decision on the number of fatal caffeine intoxications.

METHOD

In Sweden 95% of all cases undergoing forensic autopsy are screened for a number of drugs including caffeine. All cases during January 1993-September 2009 with a caffeine concentration above 80 microg/g blood were recorded.

RESULTS

During the study period toxicological investigations were performed in 83,580 forensic autopsies. Caffeine contributed to the fatal outcome in 20 cases (0.02%). Thirteen (65%) of these fatalities occurred before the introduction of the sales restriction. However, no fatal intoxications where caffeine contributed to the cause of death was recorded between May 2007 and September 2009.

CONCLUSION

Overdoses of tablets containing caffeine can be fatal, suicides as well as accidents occur. Restricting the maximum quantity of caffeine tablets available over the counter seemed to be effective in preventing suicides because of caffeine although some time elapsed until the effect was noted. Further monitoring is required to ensure that the observed lower caffeine mortality is a sustained effect.

Detailed analyses of self-poisoning episodes presenting to a large regional teaching hospital in the UK

AIMS

The primary aim of this paper is to provide comprehensive contemporaneous data on the demographics, patterns of presentation and management of all episodes of deliberate self-poisoning presenting to a large regional teaching hospital over a 12 month period.

METHODS

We undertook detailed, retrospective analyses using information from electronic patient records and local patient-tracking, pathology and administrative databases. Statistical analyses were performed using Chi-squared tests, anova and two-tailed t-tests (Graphpad Prism).

RESULTS

One thousand five hundred and ninety-eight episodes of deliberate self-poisoning presented over the year. Demographic data and information on the month, day and time of admission are provided. 70.7% presented to the emergency department (ED) within 4 h of ingestion. 76.3% of patients had only one episode in an extended 29 month follow-up period. A mean of 1.72 drugs were taken per episode with just over half of all episodes involving a single drug only. Paracetamol and ibuprofen were the two most commonly ingested drugs involved in 42.5% and 17.3% of all overdoses respectively. 56.3% of patients taking paracetamol reported ingesting over 8 g (one over the counter packet). Detailed mapping of the patients' pathway through the hospital allowed an estimation of the hospital cost of caring for this patient group at pound 1.6 million pounds per year.

CONCLUSIONS

We present comprehensive and contemporary data on presentations to hospital resulting from deliberate self-poisoning. We include demographic information, presentation patterns, drugs used, a detailed analysis of episodes involving paracetamol and an estimate of the financial burden to hospitals of overdose presentations.

Hospital admission for non-fatal poisoning with weak analgesics and risk for subsequent suicide: a population study

BACKGROUND

Poisoning with weak analgesics is a major public health problem because of easy accessibility of the compounds; however, few studies have investigated their influence on subsequent suicide in the context of subjects' psychiatric status and other factors.

METHOD

This nested case-control study was based on the entire Danish population including all 21,169 suicide cases and 423,128 matched population controls. Data on hospital admissions for poisoning and confounding factors were retrieved from national medical and administrative registries. Conditional logistic regression was used to compute relative risk.

RESULTS

A prior hospital admission for poisoning with weak non-opioid analgesics significantly increased the risk of subsequent suicide [crude incidence rate ratio (IRR) 24.7, 95% confidence interval (CI) 22.1-27.6], and the effect of paracetamol poisoning was substantially stronger than that of poisoning with salicylates or non-steroidal anti-inflammatory drugs (NSAIDs). This association could not be explained by confounding from socio-economic or psychiatric factors. The elevated risk was extremely high during the first week following the overdose (adjusted IRR 738.9, 95% CI 173.9-3139.1), then declined over time but still remained significantly high 3 years later (adjusted IRR 4.2, 95% CI 3.5-5.0). Moreover, a history of weak analgesic poisoning significantly interacted with a person's psychiatric history, increasing the risk for subsequent suicide substantially more for persons with no history of psychiatric hospitalization than did it for those with such a history.

CONCLUSIONS

A history of non-fatal poisoning with weak analgesics is a strong predictor for subsequent suicide. These results emphasize the importance of intensive psychiatric care of patients following overdose.

The FDA Acetaminophen Advisory Committee Meeting - what is the future of acetaminophen in the United States? The perspective of a committee member

BACKGROUND

Unintentional acetaminophen toxicity is a common problem throughout the world but particularly in the more developed countries. To deal with the problem, several countries have attempted to decrease the risk of acetaminophen overdose by reducing package sizes. The U.S. Food and Drug Administration (FDA) convened a joint meeting recently of three Advisory Committees to consider the issue of unintentional acetaminophen-related toxicity and to explore strategies to address the problem.

PROPOSALS AND RECOMMENDATIONS

Three strategies addressed the issue of dose reduction as a way to decrease morbidity and mortality. The FDA proposed a decrease in the maximum daily dose from 4,000 to 3,250 mg, reducing the maximum individual dose from 1,000 to 650 mg and relegating 500 mg tablets to prescription status. The Committees voted in favor of each of those initiatives. Restricting the number of doses that could be purchased by regulating package sizes, as has been done in some European countries, was proposed, but rejected by the Committees. Proposals also addressed the elimination of nonprescription and prescription acetaminophen combination products (e.g., multi-symptom cold relief combinations and acetaminophen/opioid combinations) as a strategy to decrease unintentional poisoning when individuals unknowingly take different products, all of which contain acetaminophen. The Committees rejected the proposal to eliminate the nonprescription combinations but recommended the elimination of prescription combination products. Currently, liquid acetaminophen is available in the United States in three different concentrations. To reduce the confusion associated with the variance in concentrations the Committees voted to have a single concentration for all acetaminophen liquid products. Finally, the Committees voted, almost unanimously, to encourage the FDA to place a boxed warning in the product information to create awareness among prescribers and pharmacists about acetaminophen toxicity and to educate their patients accordingly.

CONCLUSIONS

Many of the recommendations were not evidence-based but instead have an anecdotal basis. However, the Committees are advisory to the FDA, their recommendations are not binding and it remains to be seen which of the recommendations will be implemented.

Outcomes of liver transplantation for paracetamol (acetaminophen)-induced hepatic failure

Paracetamol (acetaminophen) hepatotoxicity, whether due to intentional overdose or therapeutic misadventure, is an indication for liver transplantation in selected cases. However, there is a concern that long-term outcomes may be compromised by associated psychopathology that may predispose patients to further episodes of self-harm or poor treatment adherence. We therefore undertook a retrospective analysis of patients transplanted for paracetamol-induced fulminant hepatic failure (FHF) to determine their long-term outcomes, psychiatric problems, and compliance and whether these issues could be predicted from pretransplant information. Records from patients undergoing liver transplantation for paracetamol-associated liver failure in this unit and 2 comparison groups (patients undergoing liver replacement for FHF from other causes and for chronic liver diseases) were examined. Of 60 patients transplanted for paracetamol-induced FHF between 1989 and 2007, 44 (73%) survived to discharge. Currently, 35 patients (58%) are surviving at an average of 9 years post-transplantation. The incidence of psychiatric disease (principally depression) and 30-day mortality were greatest in the paracetamol group, but for those who survived 30 days, there was no difference in long-term survival rates between the groups. Adherence to follow-up appointments and compliance with immunosuppression were lowest in the paracetamol overdose group. Poor adherence was not predicted by any identifiable premorbid psychiatric conditions. Two patients grafted for paracetamol FHF died from self-harm (1 from suicide and 1 from alcoholic liver disease after 5 years). This study suggests that, notwithstanding the shortage of donor liver grafts, transplantation is an appropriate therapy in selected patients, although close follow-up is indicated.

Single dose oral paracetamol (acetaminophen) with codeine for postoperative pain in adults

BACKGROUND

This is an updated version of the Cochrane review published in Issue 4, 1998. Combining drugs from different classes with different modes of action may offer opportunity to optimise efficacy and tolerability, using lower doses of each drug to achieve the same degree of pain relief. Previously we concluded that addition of codeine to paracetamol provided additional pain relief, but at expense of additional adverse events. New studies have been published since. This review sought to evaluate efficacy and safety of paracetamol plus codeine using current data, and compare findings with other analgesics evaluated similarly.

OBJECTIVES

Assess efficacy of single dose oral paracetamol plus codeine in acute postoperative pain, increase in efficacy due to the codeine component, and associated adverse events.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, the Oxford Pain Relief Database in October 2008 for this update.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled trials of paracetamol plus codeine, compared with placebo or the same dose of paracetamol alone, for relief of acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted data. The area under the "pain relief versus time" curve was used to derive proportion of participants with paracetamol plus codeine and placebo or paracetamol alone experiencing least 50% pain relief over four-to-six hours, using validated equations. Number-needed-to-treat-to-benefit (NNT) was calculated using 95% confidence intervals (CIs). Proportion of participants using rescue analgesia over a specified time period, and time to use of rescue analgesia, were sought as additional measures of efficacy. Information on adverse events and withdrawals were collected.

MAIN RESULTS

Twenty-six studies, with 2295 participants, were included comparing paracetamol plus codeine with placebo. Significant dose response was seen for the outcome of at least 50% pain relief over four-to-six hours, with NNTs of 2.2 (95% CI 1.8 to 2.9) for 800 to 1000 mg paracetamol plus 60 mg codeine, 3.9 (2.9 to 4.5) for 600 to 650 mg paracetamol plus 60 mg codeine, and 6.9 (4.8 to 12) for 300 mg paracetamol plus 30 mg codeine. Time to use of rescue medication was over four hours with paracetamol plus codeine and two hours with placebo. The NNT to prevent remedication was 5.6 (4.0 to 9.0) for 600 mg paracetamol plus 60 mg codeine over four to six hours. Adverse events increased of mainly mild to moderate severity with paracetamol plus codeine than placebo.Fourteen studies, with 926 participants, were included in the comparison of paracetamol plus codeine with the same dose of paracetamol alone. Addition of codeine increased proportion of participants achieving at least 50% pain relief over four-to-six hours by 10 to 15%, increased time to use of rescue medication by about one hour, and reduced proportion of participants needing rescue medication by about 15% (NNT to prevent remedication 6.9 (4.2 to 19). Adverse events were mainly mild to moderate in severity and incidence did not differ between groups.

AUTHORS' CONCLUSIONS

This update confirms previous findings that combining paracetamol with codeine provided clinically useful levels of pain relief in about 50% of patients with moderate to severe postoperative pain, compared with under 20% with placebo. New information for remedication shows that the combination extended the duration of analgesia by about one hour compared to treatment with the same dose of paracetamol alone. At higher doses, more participants experienced adequate pain relief, but the amount of information available for the 1000 mg paracetamol plus 60 mg codeine dose was small, and based on limited information.

Single dose oral paracetamol (acetaminophen) for postoperative pain in adults

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 1, 2004 - this original review had been split from a previous title on 'Single dose paracetamol (acetaminophen) with and without codeine for postoperative pain'. The last version of this review concluded that paracetamol is an effective analgesic for postoperative pain, but additional trials have since been published. This review sought to evaluate the efficacy and safety of paracetamol using current data, and to compare the findings with other analgesics evaluated in the same way.

OBJECTIVES

To assess the efficacy of single dose oral paracetamol for the treatment of acute postoperative pain.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, EMBASE, the Oxford Pain Relief Database and reference lists of articles to update an existing version of the review in July 2008.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled clinical trials of paracetamol for acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Area under the "pain relief versus time" curve was used to derive the proportion of participants with paracetamol or placebo experiencing at least 50% pain relief over four to six hours, using validated equations. Number-needed-to-treat-to-benefit (NNT) was calculated, with 95% confidence intervals (CI). The proportion of participants using rescue analgesia over a specified time period, and time to use, were sought as measures of duration of analgesia. Information on adverse events and withdrawals was also collected.

MAIN RESULTS

Fifty-one studies, with 5762 participants, were included: 3277 participants were treated with a single oral dose of paracetamol and 2425 with placebo. About half of participants treated with paracetamol at standard doses achieved at least 50% pain relief over four to six hours, compared with about 20% treated with placebo. NNTs for at least 50% pain relief over four to six hours following a single dose of paracetamol were as follows: 500 mg NNT 3.5 (2.7 to 4.8); 600 to 650 mg NNT 4.6 (3.9 to 5.5); 975 to 1000 mg NNT 3.6 (3.4 to 4.0). There was no dose response. Sensitivity analysis showed no significant effect of trial size or quality on this outcome.About half of participants needed additional analgesia over four to six hours, compared with about 70% with placebo. Five people would need to be treated with 1000 mg paracetamol, the most commonly used dose, to prevent one needing rescue medication over four to six hours, who would have needed it with placebo. Adverse event reporting was inconsistent and often incomplete. Reported adverse events were mainly mild and transient, and occurred at similar rates with 1000 mg paracetamol and placebo. No serious adverse events were reported. Withdrawals due to adverse events were uncommon and occurred in both paracetamol and placebo treatment arms.

AUTHORS' CONCLUSIONS

A single dose of paracetamol provides effective analgesia for about half of patients with acute postoperative pain, for a period of about four hours, and is associated with few, mainly mild, adverse events.

Paracetamol (acetaminophen) pack size restrictions and poisoning severity: time trends in enquiries to a UK poisons centre

BACKGROUND AND OBJECTIVE

In September 1998, legislation was introduced in the United Kingdom to limit paracetamol pack sizes to 16 tablets of 500 mg at general sales outlets and 32 tablets of 500 mg at pharmacies. The effect of the regulations on severity of paracetamol poisoning is unclear. The aim of this study was to describe trends in the severity of paracetamol poisoning and to assess the impact of the 1998 Regulations on the enquiries to a UK poisons centre.

METHODS

We extracted data about the age, sex and number of tablets or capsules of paracetamol ingested by patients notified to Guy's and St Thomas' Poisons Unit (London, UK) between 1996 and 2004.

RESULTS AND DISCUSSION

During the study period, there were approximately 140 000 patients with suspected paracetamol poisoning, accounting for around 11% of all patients reported to the poisons unit. The median number of tablets fell from 25 to 20 for males and 20 to 16 for females after 1998. There was also a reduction in the proportion of patients who ingested 17-32 tablets (from 36% to 30%) and 33-100 tablets (from 25% to 19%).

CONCLUSION

Following the 1998 Regulations there was a decline in the severity, but not frequency, of paracetamol poisoning cases reported to Guy's and St Thomas' Poisons Unit. It is unclear whether the decline in severity was a direct consequence of the regulations.