Drug Interactions with Paracetamol

The Burden of Inappropriate Prescriptions and Predictors for Hospitalized Patients with Liver Cirrhosis in Ethiopia

Background

Pathophysiological alterations in liver cirrhosis affect how medications are metabolized and eliminated. Therefore, when prescribing medicines for patients with cirrhosis, appropriate prescription of medication is an accepted standard of practice. Since patients with cirrhosis require a complex therapy plan, it necessitates regular reviews of medication utilization. However, no research was conducted in Ethiopia. The aim of this study was to figure out the predictors of inappropriate prescriptions and the pattern of prescription in patients with cirrhosis.

Patients and methods

A cross-sectional study design was carried out at Felege-Hiwot, a specialized and comprehensive referral hospital, from June 30, 2022, to November 30, 2022, in 123 hospitalized patients with cirrhosis. Patients were recruited using a simple random sampling procedure, and data were collected using an interviewer-administered questionnaire. For the purpose of identifying determinants of inappropriate prescription, logistic regression analyses have been carried out and statistical significance was defined by a p-value of less than 0.05 and a 95% confidence range.

Results

The burden of inappropriate prescriptions among patients with cirrhosis was 35.8%. An increased number of medications prescribed (AOR = 4.88 (1.05-22.68)), prescription by a general practitioner (AOR = 3.57 (95% CI 1.07-11.44)), increased level of bilirubin (AOR = 3.54 (95% CI 1.95-6.45)), and decreased level of albumin (AOR = 0.18 (95% CI 0.04-0.72)) were predictors for an inappropriate prescription.

Conclusion

It has been found that there were inappropriate prescriptions among patients with liver cirrhosis. Prescribers should pay close attention to patients who have prescribed with higher number of medications, increased level of bilirubin and decreased level of albumin. Moreover, educational level of prescribers needs to be upgraded in order to adopt evidence-based medication prescriptions and adhere to recommended practices.

Why paracetamol (acetaminophen) is a suitable first choice for treating mild to moderate acute pain in adults with liver, kidney or cardiovascular disease, gastrointestinal disorders, asthma, or who are older

Acute pain is among the most common reasons that people consult primary care physicians, who must weigh benefits versus risks of analgesics use for each patient. Paracetamol (acetaminophen) is a first-choice analgesic for many adults with mild to moderate acute pain, is generally well tolerated at recommended doses (≤4 g/day) in healthy adults and may be preferable to non-steroidal anti-inflammatory drugs that are associated with undesirable gastrointestinal, renal, and cardiovascular effects. Although paracetamol is widely used, many patients and physicians still have questions about its suitability and dosing, especially for older people or adults with underlying comorbidities, for whom there are limited clinical data or evidence-based guidelines. Inappropriate use may increase the risks of both overdosing and inadequate analgesia. To address knowledge deficits and augment existing guidance in salient areas of uncertainty, we have researched, reviewed, and collated published evidence and expert opinion relevant to the acute use of paracetamol by adults with liver, kidney, or cardiovascular diseases, gastrointestinal disorders, asthma, or/and who are older. A concern is hepatotoxicity, but this is rare among adults who use paracetamol as directed, including people with cirrhotic liver disease. Putative epidemiologic associations of paracetamol use with kidney or cardiovascular disease, hypertension, gastrointestinal disorders, and asthma largely reflect confounding biases and are of doubtful relevance to short-term use (<14 days). Paracetamol is a suitable first-line analgesic for mild to moderate acute pain in many adults with liver, kidney or cardiovascular disease, gastrointestinal disorders, asthma, and/or who are older. No evidence supports routine dose reduction for older people. Rather, dosing for adults who are older and/or have decompensated cirrhosis, advanced kidney failure, or analgesic-induced asthma that is known to be cross-sensitive to paracetamol, should be individualized in consultation with their physician, who may recommend a lower effective dose appropriate to the circumstances.

In vivo effect of Kaempferia parviflora extract on pharmacokinetics of acetaminophen

Kaempferia parviflora is widely used as a food supplement and a herbal medicine for vitalization. Previous study has shown that K. parviflora had CYP2E1 inducer activity. It is likely to affect the metabolism of CYP2E1 substrates such as acetaminophen which is a common household pain relief medicine. This study investigated the possible pharmacokinetic interaction between K. parviflora and acetaminophen in rats. Acetaminophen (100 mg/kg, p.o) was administered to rats for nine consecutive days. On days 4-9, K. parviflora extract (250 mg/kg, p.o) was given to the acetaminophen-treated rats. After co-administration with K. parviflora, the concentrations of acetaminophen during day 5-8 markedly decreased compared with acetaminophen-only group. At day 9, the pharmacokinetic parameters of acetaminophen in the presence of K. parviflora extract also decreased, including area under the concentration-time curve (from 1.68 ± 0.16 to 0.34 ± 0.04 mg.min/mL), the maximum concentration (from 19.10 ± 1.90 to 4.48 ± 0.56 µg/mL), and half-life (from 21.29 ± 1.36 to 10.81 ± 1.24 min). In addition, clearance and the elimination rate constant of acetaminophen were significantly increased (from 0.003 ± 0.000 to 0.006 ± 0.001 L/min and 0.03 ± 0.00 to 0.07 ± 0.01 min^-1, respectively) in the presence of K. parviflora extract. These findings provide the data for in vivo herb-drug interaction between K. parviflora extract and acetaminophen. Therefore, the concomitant use of K. parviflora as a food supplement and acetaminophen should occasion therapeutic and safety concerns.

Postoperative Pain Among Patients After Day-Case Surgery

Postoperative pain occurs at a high incidence after day-case surgery, with many patients reporting moderate to severe pain. A cross-sectional design was used in this study to estimate the prevalence of postoperative pain in the early postoperative period after day-case surgery and to determine whether there is a relationship between demographic and clinical variables. A convenient sample of 300 patients, aged between 18 and 80 years, was selected from all postoperative patients after day-case surgery over a period of 6 months. At the first 2 hr after surgery, about 70% of patients had either no pain or mild pain at rest and about 30% of patients had moderate to severe pain. About one third of these patients (103; 35.8%) reported mild pain, and about 43% of patients had moderate to severe pain on movement in the first 2 hr after surgery. Furthermore, 25.3% and 41.3% of the patients reported moderate to severe pain during the first 24 hr after hospital discharge at rest and on movement, respectively. Female patients had significantly higher pain scores than male patients (p < .001). Significant decrease in pain scores was reported in the first 2 hr after surgery (mean = 2.2, SD = 2) and within the first 24 hr after discharge (mean = 1.8, SD = 2.2, t(288) = 4.3, p =. 005) at rest. The prevalence of pain among postoperative patients after day-care surgery in Jordan is high. Young adult and female patients have higher pain scores after day-case surgery.

Are some people at increased risk of paracetamol-induced liver injury? A critical review of the literature

Purpose

Paracetamol is one of the world’s most commonly used drugs. In overdose, it is well established to be hepatotoxic. The aim of this review was to identify factors that have been, or actually are, associated with the development of liver injury after paracetamol exposure in humans.

Method

Google Scholar and PubMed were searched on various dates between December 2016 and March 2017. Papers identified had their references analysed for further studies that might be relevant.

Results

At the time of writing, there was little good quality clinical evidence—from studies of paracetamol overdose or therapeutic use—to suggest that any groups of people are relatively protected from, or are at greater risk of, liver injury. The factors that were historically used to indicate higher risk in the UK have no good quality clinical evidence to support their re-introduction into clinical practice. The safe (and still effective) oral dose of paracetamol in patients weighing less than 50 kg has not been established.

Conclusion

There is no patient group that is unequivocally at elevated risk of paracetamol-induced liver toxicity. We propose two clinical scenarios that warrant further research. Firstly, there is a need to establish whether the dose of paracetamol should be reduced in patients with low body weight. Secondly, if or when genomic information regarding individual patients becomes readily available to inform prescribing, we propose the contribution of the genome to paracetamol toxicity should be re-investigated with robustly designed studies. Such studies could enhance the safe use of one of the most frequently taken drugs.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2356-6) contains supplementary material, which is available to authorized users.

Identifying adults at risk of paracetamol toxicity in the acute dental setting: development of a clinical algorithm

Paracetamol is widely used and effective for the management of dental pain in the UK. Acute dental pain is a recognised precipitant of unintentional paracetamol overdose and in a small but significant number of cases this results in hepatotoxicity. Patients' understanding of the risks of excess paracetamol ingestion remains poor and risk of over-medication before presentation is increased due to a variety of factors including dental anxiety and fragmented provision of dental emergency services. Early recognition of overdose is crucial to preventing significant hepatotoxicity and death. Dentists have a role to play in recognising unintentional overdose cases and directing patients timeously to appropriate medical care. Guidelines on the treatment of paracetamol toxicity are readily available but our data suggests some dental settings may present a weak link in the care pathway and overdose may not be readily recognised. We have developed an algorithm and training package targeted at dentists in the acute dental setting with the aim of improving recognition of paracetamol toxicity in adults and directing onward referral appropriately. This paper also revises the key pharmacokinetics and pharmacodynamics of paracetamol and is intended to raise awareness of issues of toxicity for dentists.

Can paracetamol (acetaminophen) be administered to patients with liver impairment?

Although 60 years have passed since it became widely available on the therapeutic market, paracetamol dosage in patients with liver disease remains a controversial subject. Fulminant hepatic failure has been a well documented consequence of paracetamol overdose since its introduction, while short and long term use have both been associated with elevation of liver transaminases, a surrogate marker for acute liver injury. From these reports it has been assumed that paracetamol use should be restricted or the dosage reduced in patients with chronic liver disease. We review the factors that have been purported to increase risk of hepatocellular injury from paracetamol and the pharmacokinetic alterations in different pathologies of chronic liver disease which may affect this risk. We postulate that inadvertent under-dosing may result in concentrations too low to enable efficacy. Specific research to improve the evidence base for prescribing paracetamol in patients with different aetiologies of chronic liver disease is needed.

Combining ibuprofen and acetaminophen for acute pain management after third-molar extractions: translating clinical research to dental practice

BACKGROUND

Effective and safe drug therapy for the management of acute postoperative pain has relied on orally administered analgesics such as ibuprofen, naproxen and acetaminophen, or N-acetyl-p-aminophenol (APAP), as well as combination formulations containing opioids such as hydrocodone with APAP. The combination of ibuprofen and APAP has been advocated in the last few years as an alternative therapy for postoperative pain management. The authors conducted a critical analysis to evaluate the scientific evidence for using the ibuprofen-APAP combination and propose clinical treatment recommendations for its use in managing acute postoperative pain in dentistry.

TYPES OF STUDIES REVIEWED

The authors used quantitative evidence-based reviews published by the Cochrane Collaboration to determine the relative analgesic efficacy and safety of combining ibuprofen and APAP. They found additional articles by searching the Ovid MEDLINE, PubMed and ClinicalTrials.gov databases.

CONCLUSIONS

The results of the quantitative systematic reviews indicated that the ibuprofen-APAP combination may be a more effective analgesic, with fewer untoward effects, than are many of the currently available opioid-containing formulations. In addition, the authors found several randomized controlled trials that also indicated that the ibuprofen-APAP combination provided greater pain relief than did ibuprofen or APAP alone after third-molar extractions. The adverse effects associated with the combination were similar to those of the individual component drugs. Practical Implications. Combining ibuprofen with APAP provides dentists with an additional therapeutic strategy for managing acute postoperative dental pain. This combination has been reported to provide greater analgesia without significantly increasing the adverse effects that often are associated with opioid-containing analgesic combinations. When making stepwise recommendations for the management of acute postoperative dental pain, dentists should consider including ibuprofen-APAP combination therapy.

Concomitant drugs with low risks of drug-drug interactions for use in oncology clinical trials

BACKGROUND

Drug-drug interactions (DDIs) may occur with investigational drugs and affect patient safety, trial outcomes, and drug development. A list of preferred drugs with minimal risks of DDIs for treatment of symptoms or comorbidities frequently encountered by cancer patients would be helpful.

METHODS

We reviewed the literature to assess DDIs reported for the main drugs available for treatment of symptoms/comorbidities frequently encountered by cancer patients. Reviews and relevant original articles cited were retrieved and analyzed, and the following data were collected and double-checked: pharmacological properties; effects, if any, of drugs on CYP enzymes, membrane transporters, and QT interval; and involvement in significant DDIs.

RESULTS

A list of preferred drugs with minimal risks of DDIs was compiled.

CONCLUSION

Acknowledging for heterogeneity in data sources, prevention of unexpected DDIs during clinical trials may be improved by using this list of preferred drugs for the management of study patient's symptoms.

Effects of single-dose injectable paracetamolversus propacetamol in pain management after minor gynecologic surgery: A multicenter, randomized, double-blind, active-controlled, two-parallel-group study

BACKGROUND

Intravenous administration is the route of choice for drug therapy in the immediate postoperative period. Propacetamol (ProAPAP), an injectable prodrug of paracetamol requiring reconstitution, has demonstrated efficacy in managing acute pain and fever. However, it has been associated with pain at the injection site. A stable, ready-to-use formulation of paracetamol solution infused intravenously (IV-APAP) has been developed and might be associated with less pain at the injection site compared with ProAPAR.

OBJECTIVE

The objective of this study was to assess the tolerability and efficacy of a single dose of IV APAP 1 g compared with those of a single dose of ProAPAP 2 g in patients with moderate to severe pain after minor gynecologic surgery.

METHODS

This single-dose, randomized, double-blind, active-controlled,2-parallel-group study was conducted at 23 hospitals and outpatient clinics in France. After minor gynecologic surgery, patients reporting moderate to severe pain were randomized to receive a single 15-minute infusion of IV-APAP 1 g or ProAPAP 2 g (bioeyuivalent doses). Tolerability was monitored using local and systemic adverse event (AE) reporting, clinical examination including vital sign measurement, and patients' ratings of acceptability of the infusion. Efficacy end points included pain intensity at 0, 1, 2, 4, and 6 hours; median time to rescue medication (defined as the time at which 50% of patients requested rescue medication); and percentage of patients requesting rescue medication. Patients' satisfaction with the study drugs was assessed using patient's global evaluation (PGE) and the percentage of patients willing to receive the treatment again.

RESULTS

Of the 163 women who were randomized, 161 received the studymedication. The IV-APAP group comprised 80 patients (mean [SD] age, 38.3 [12.8] years [range, 18.0-69.0 years]; mean [SD] weight, 61.1 [11.0] kg [range, 49.0-90.0 kg]), and the ProAPAP group comprised 81 patients (mean [SD] age, 33.9 [12.0] years [range, 18.0-67.0 years]; mean [SD] weight, 61.6 [10.2] kg [range, 42.0-95.5 kg]); the difference in mean age between the 2 groups was statistically significant (P < 0.05). The incidence of local treatment-emergent AEs (TEAEs) was significantly lower in the IV-APAP group compared with that in the ProAPAP group (7.5% vs 38.3%; P < 0.001). No between-group differences in the incidence of systemic TEAEs was found. All patients in the IV-APAP group found the infusion tolerable, compared with 95% of patients in the ProAPAP group. The median time to rescue medication was not evaluated because <50% of the patients in each group requested it. No significant differences in mean pain intensity score or percentage of patients requesting rescue medication were found between the 2 groups at any time point. The percentages of patients in the IV-APAP and ProAPAP groups who rated the study medication as good or excellent on the PGE (83.6% vs 75.6%; P < 0.05) and who were willing to receive the same treatment again (96.0% vs 81.0%; P = 0.005) were significantly higher with IV-APAP compared with ProAPAP.

CONCLUSION

In these patients with moderate to severe pain after minor gynecologic surgery, a single dose of IV-APAP was associated with better local tolerability, similar analgesic efficacy, and greater patient satisfaction compared with a single bioequivalent dose of ProAPAP.

The therapeutic applications of and risks associated with acetaminophen use: a review and update

BACKGROUND

In response to the April 2010 U.S. Food and Drug Administration's (FDA's) revision of warning labeling for over-the-counter (OTC) acetaminophen, or N-acetyl-p-aminophenol (APAP), products, the authors reviewed APAP's potential for liver toxicity.

TYPES OF STUDIES REVIEWED

The authors reviewed the literature in which investigators examined data related to the epidemiology of APAP-related liver toxicity, studies in which the investigators evaluated the risk factors for its occurrence and case reports. They included articles that were used by the FDA as the basis for establishing the new labeling requirements.

RESULTS

Findings from the literature in which investigators have examined the relationship between APAP and liver toxicity indicate several key risk factors. Foremost are the extensive use of one or more APAP-containing compounds (particularly combinations with opioid agents) and the small margin of safety between the therapeutic and toxic doses. Both of these factors lead to unintentional or intentional drug overdose. Concurrent use of alcohol may contribute to hepatotoxicity, but it may be related to behavior rather than biochemical mechanisms involved in liver damage.

CONCLUSIONS

The widespread use of APAP has contributed to a substantial increase in the number of cases of acute liver toxicity in the United States. Since APAP is a component of many prescription and OTC medications, unintentional overdose can occur.

CLINICAL IMPLICATIONS

APAP has numerous applications in dentistry, but if it is used conjointly for other conditions, the risk of the patient's experiencing an overdose increases. In the context of recent FDA concerns about the increased incidence of APAP-related liver toxicity, the authors provide recommendations for safe prescribing practices for APAP. Practitioners should caution patients to follow recommended dosage instructions and avoid taking multiple APAP-containing products.

Responsible self-medication: perceived risks and benefits of over-the-counter analgesic use

OBJECTIVES

This study examines awareness of the potential risks associated with over-the-counter (OTC) use of paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) among Australian consumers to better understand patterns of usage of these products.

METHODS

We employed two self-reported cross-sectional surveys (conducted in 2001 and 2009) using computer-aided telephone interviewing. Both survey samples were weighted to match national population proportions; data were collected for 3702 respondents (study 1, 2001, n=1901; study 2, 2009, n=1801). The inclusion criteria were age over 18 years and willingness to participate in the survey.

KEY FINDINGS

Self-reported regular use (once or more per month) of OTC analgesics declined between 2001 (67.5%) and 2009 (55.0%; P<0.05). In 2009 42.0% of regular OTC analgesic users were purchasing NSAIDs outside the pharmacy setting (compared with none in 2001). Stated awareness of potential risks has increased slightly among regular paracetamol users (from 49.0% in 2001 to 52.0% in 2009) and regular NSAID users (from 25.0% in 2001 to 41.0% in 2009). Regular OTC analgesic users were considered to be using the product appropriately if there were no contraindications, warnings, precautions or potential drug interactions to the analgesic that they had used. In 2001, significantly more people were using paracetamol appropriately than were using NSAIDs appropriately (98.3 compared with 79.3%; P<0.05). Corresponding figures for 2009 were 96.4 and 69.1% (P<0.5).

CONCLUSIONS

Increasing consumer awareness of the need to consider potential risks prior to taking OTC analgesics is a positive sign. However, this has not translated to an increase in appropriate use of OTC NSAIDs; since ibuprofen has become available outside the pharmacy setting in Australia fewer people are using NSAIDs appropriately according to the label. The quality use of medicines, in particular OTC NSAIDs, is becoming increasingly reliant on product labelling and the ability of consumers to understand and self-assess risk.

Interaction between acetaminophen and warfarin in adults receiving long-term oral anticoagulants: a randomized controlled trial

PURPOSE

We investigated whether acetaminophen, given at 2 g/day and 3 g/day might potentiate the anticoagulant effect of warfarin.

METHODS

Forty-five patients on stable warfarin therapy, enrolled in this prospective, randomized, parallel (three arms), placebo-controlled study, received a 10-day regimen of acetaminophen (2 g/day or 3 g/day) or placebo.

RESULTS

The mean maximal INR increase was 0.70 ± 0.49 and 0.67 ± 0.62 in patients receiving acetaminophen at 2 g/day and 3 g/day, respectively (P=0.01 for the respective comparisons versus placebo). The INR increase became significant on day 3 and was independently and significantly predicted by a maximal decrease in factor II (R(2)=0.36, P<0.0001), factor VII (R (2)=0.46, P<0.0001) and a maximal increase in acetaminophen plasma concentrations (R(2)=0.563, P<0.0001).

CONCLUSION

Acetaminophen, at 2 g/day or 3 g/day, enhanced the anticoagulant effect of warfarin in stable patients, thus requiring close INR monitoring in the clinical setting.

Peri-operative use of paracetamol

This article is a review of the peri-operative use of paracetamol. It reviews the pharmacology of paracetamol, highlighting new information about the mechanism of action, and examines its therapeutic use in the peri-operative period, focusing on efficacy, route of administration, and the use of a loading dose to improve early postoperative analgesia.

Acetaminophen hepatotoxicity

Acetaminophen is a commonly used antipyretic and analgesic agent. It is safe when taken at therapeutic doses; however, overdose can lead to serious and even fatal hepatotoxicity. The initial metabolic and biochemical events leading to toxicity have been well described, but the precise mechanism of cell injury and death is unknown. Prompt recognition of overdose, aggressive management, and administration of N-acetylcysteine can minimize hepatotoxicity and prevent liver failure and death. Liver transplantation can be lifesaving for those who develop acute liver failure.

Pharmacokinetics and interactions of headache medications, part I: introduction, pharmacokinetics, metabolism and acute treatments

Recent progress in the treatment of primary headaches has made available specific, effective and safe medications for these disorders, which are widely spread among the general population. One of the negative consequences of this undoubtedly positive progress is the risk of drug-drug interactions. This review is the first in a two-part series on pharmacokinetic drug-drug interactions of headache medications. Part I addresses acute treatments. Part II focuses on prophylactic treatments. The overall aim of this series is to increase the awareness of physicians, either primary care providers or specialists, regarding this topic. Pharmacokinetic drug-drug interactions of major severity involving acute medications are a minority among those reported in literature. The main drug combinations to avoid are: i) NSAIDs plus drugs with a narrow therapeutic range (i.e., digoxin, methotrexate, etc.); ii) sumatriptan, rizatriptan or zolmitriptan plus monoamine oxidase inhibitors; iii) substrates and inhibitors of CYP2D6 (i.e., chlorpromazine, metoclopramide, etc.) and -3A4 (i.e., ergot derivatives, eletriptan, etc.), as well as other substrates or inhibitors of the same CYP isoenzymes. The risk of having clinically significant pharmacokinetic drug-drug interactions seems to be limited in patients with low frequency headaches, but could be higher in chronic headache sufferers with medication overuse.

Interaction between warfarin and cranberry juice

Warfarin is extensively used for anticoagulation to a target international normalized ratio of 2.0-3.0 for most indications or 2.5-3.5 for high-risk indications; however, many drugs and dietary supplements induce fluctuations in the international normalized ratio. Such fluctuations may lead to therapeutic failure or bleeding complications. Cranberry juice is increasingly used for the prevention and adjunctive treatment of urinary tract infections. The United Kingdom's Committee on Safety of Medicines has alerted clinicians to a potential interaction between warfarin and cranberry juice and has advised that patients avoid their concurrent use. Review and analysis of the literature revealed that ingestion of large volumes of cranberry juice destabilize warfarin therapy. Small amounts of juice are not expected to cause such an interaction. Clinicians should be aware of this potential interaction and monitor and counsel patients accordingly.

A prospective survey to compare the suitability profiles of over-the-counter ibuprofen and paracetamol use in a French general practitioner-controlled population

BACKGROUND AND OBJECTIVES

The PAIN (Paracetamol, Aspirin and Ibuprofen New tolerability) study published in 1999 assessed the tolerability of over-the- counter (OTC) analgesics in a French general practitioner (GP)-controlled population and found no apparent difference between the tolerability of ibuprofen and paracetamol (acetaminophen). However, patient selection in that study could cast doubt over the relevance of the results to a more generalised OTC population. The aim of our survey was to prospectively determine what proportion of a French GP-controlled population is able to take ibuprofen and paracetamol in order to allow appropriate interpretation of the PAIN study.

METHODS

This was a prospective survey to identify all contraindications/warnings on product labelling for ibuprofen and paracetamol in 5000 patients aged 18-75 years. 100 French GPs each collected anonymised data on 50 patients over a 1-week period using a standardised form. GPs were stratified by geographical location and size of practice. Demographic data for patients were summarised. Contraindications/warnings for ibuprofen and paracetamol were summarised overall and by individual criterion.

RESULTS

The mean age of patients was 45.8 (+/- 16.5) years; 42% were males and 58% females. Of these patients, 49.9% would have been ineligible for the PAIN study because of at least one contraindication/warning for ibuprofen, whereas only 6.8% would have been ineligible because of at least one contraindication/warning for paracetamol. More specifically, contraindications to use of ibuprofen was noted in 12.3% of patients and 37.6% of patients should have consulted a doctor before use of this drug. In contrast, contraindications to use of paracetamol were noted in only 0.7% of patients and only 6.1% should have consulted a doctor before use of this drug.

CONCLUSIONS

Our survey demonstrates how careful patient selection can limit the generalisability of a study. The PAIN study excluded individuals 'at-risk' from ibuprofen and the tolerability results of this study should therefore be interpreted with extreme caution because the patient population may not be representative of unsupervised OTC analgesic users.

Drug-induced liver disease

PURPOSE OF REVIEW

To summarize the pertinent case reports, case series and clinical studies that described clinical, histological, epidemiological and mechanistic features of drug-induced liver disease in 2005.

RECENT FINDINGS

Acetaminophen, highly active antiretroviral therapy and drugs for tuberculosis retained their preeminent position as the most commonly reported agents causing drug-induced liver disease, with acetaminophen continuing to be the leading cause of acute liver failure in the USA. While the frequency of drug-induced liver disease remains low, a large case-series of acute drug-induced liver disease from Spain and Sweden supported the observation that acute hepatocellular jaundice from a drug is associated with death or the need for transplant in at least 10% (known as Hy's Law). With respect to using potentially hepatotoxic medications in patients with underlying liver disease, statins and second-generation thiazolidinediones were shown to be safe when used in patients with elevated baseline alanine aminotransferase or aspartate aminotransferase levels.

SUMMARY

Drug-induced liver disease remains an important cause of acute liver failure, and research efforts by the National Institutes of Health and others are underway to better determine the risk factors and other host susceptibilities that will allow for the safer use of drugs in the future.