Pyroglutamate acidosis 2023. A review of 100 cases

This review concerns the rare, acquired, usually iatrogenic, high-anion-gap metabolic acidosis, pyroglutamic acidosis. Pyroglutamate is a derivative of the amino acid glutamate, and is an intermediate in the 'glutathione cycle', by which glutathione is continuously synthesized and broken down. The vast majority of pyroglutamic acidosis cases occur in patients on regular, therapeutic doses of paracetamol. In about a third of cases, flucloxacillin is co-prescribed. In addition, the patients are almost always seriously unwell in other ways, typically with under-nourishment of some form. Paracetamol, with underlying disorders, conspires to divert the glutathione cycle, leading to the overproduction of pyroglutamate. Hypokalaemia is seen in about a third of cases. Once the diagnosis is suspected, it is simple to stop the paracetamol and change the antibiotic (if flucloxacillin is present), pending biochemistry. N-acetyl-cysteine can be given, but while the biochemical justification is compelling, the clinical evidence base is anecdotal.

[Flucloxacillin-induced hypokalemia]

Flucloxacillin-induced hypokalaemia can be progressive and life-threatening, despite of potassium supplementation. In this case description, a high dose of intravenous flucloxacillin was started after a 68-year-old patient presented with an infected knee replacement. After two days, hypokalaemia was noted with an inadequate response to potassium supplementation. It was decided to change antibiotics and increase potassium supplementation, with good results. It is advisable to include monitoring of potassium levels in local treatment protocols when flucloxacillin is prescribed.

Incidence and predisposing factors for flucloxacillin-related hepatotoxicity in children

BACKGROUND

Flucloxacillin-induced hepatotoxicity is well established in adults. However, there are few paediatric studies of flucloxacillin-induced hepatotoxicity despite this drug being among the most commonly prescribed in children. We aimed to determine the incidence of flucloxacillin-induced hepatotoxicity in children receiving IV therapy as well as identify risk factors for this adverse drug reaction.

METHODS

We undertook a 2 year retrospective audit of children aged 0-18 years admitted to the Royal Children's Hospital (March 2019 to March 2021) who had liver function tests determined before and after receiving IV flucloxacillin for at least 24 hours duration. Causality was assessed using the Roussel Uclaf Causality Assessment Method and Naranjo criteria.

RESULTS

Overall, the incidence of hepatotoxicity was 66/393 (17%). The median age of children with hepatotoxicity was 1.1 years (IQR 0.3-11.9), 43 (65%) received two or more concomitant hepatotoxic medications and 23 (35%) were receiving total parenteral nutrition. The median timing of onset of hepatotoxicity after commencement of flucloxacillin was 4 days (range 2-7). Severe hepatotoxicity (Common Terminology Criteria for Adverse Events grade 3 or above) occurred in 9/66 (14%) for bilirubin, 13/66 (20%) for ALT and 10/66 (15%) for GGT. Predisposing factors for hepatotoxicity were increasing age (OR 1.06 per additional year, 95% CI 1.01-1.10, P = 0.02), with adolescents aged 12-18 years having the highest risk (OR 5.10, 95% CI 2.02-12.85, P = 0.001), and two or more concomitant hepatotoxic medications (OR 2.51, 95% CI 1.02-6.18, P = 0.05). The median time to resolution of hepatotoxicity after cessation of flucloxacillin was 5 days (range 2-10).

CONCLUSIONS

In children, older patients and those receiving two or more concomitant hepatotoxic medications are at greater risk of flucloxacillin-induced hepatotoxicity.

Development of mouse models with restricted HLA-B∗57:01 presentation for the study of flucloxacillin-driven T-cell activation and tolerance in liver injury

BACKGROUND

Flucloxacillin (FLX)-induced liver injury is immune-mediated and highly associated to HLA-B∗57:01 expression. Host factors leading to drug-induced liver injury are not yet well understood.

OBJECTIVE

Characterize in vivo immune mechanisms determining the development of CD8+ T cells reactive to FLX in animals expressing the risk human leukocyte antigen (HLA) allotype.

METHODS

HLA-B∗57:01 transgenic mice (Tg) or Tg strains with H2-KbDb knockout (Tg/KO) or H2-KbDb/PD-1 double knockout (Tg/DKO) were treated with drug and/or anti-CD4 antibody. Drug-induced liver injury was evaluated on the basis of liver enzyme and histologic changes at day 10 of treatment. FLX-reactive CD8+ T cells were characterized in vitro by release of effector molecules on drug restimulation, gene expression, and flow cytometry analysis, and functionality tested for hepatic cytotoxicity.

RESULTS

CD8+ T-cell responses to FLX in Tg were dependent on both HLA and mouse major histocompatibility complex I presentation and in vivo priming. Eliminating H2-KbDb in Tg/KO to allow exclusive presentation of FLX by HLA resulted in a less robust drug-specific CD8+T-cell response unless CD4+ cells, including regulatory T cells, were depleted. Treatment of Tg/KO with anti-CD4 antibody and FLX led to subclinical liver inflammation associated with an increase in PD1+CD8+ T cells in the lymphoid organs and liver. Impaired PD-1 expression in Tg/DKO led to liver histopathologic and transcriptional alterations but without hepatic enzyme elevations. Moreover, effector lymphocytes accumulated in the liver and showed FLX-dependent hepatic cytotoxicity in vitro when tolerogenic liver cells were depleted.

CONCLUSIONS

In our in vivo models, FLX primes CD8+ T cells to recognize drug presented by HLA-B∗57:01 and murine major histocompatibility complex I. HLA-B∗57:01-dependent CD8+ T-cell reaction to FLX is limited by the presence of CD4+ cells, presumably regulatory T cells, and PD-1 expression. Tolerogenic hepatic cells limit clinical disease through PD-L1 or additional unexplored mechanisms.

[A case of pyroglutamic metabolic acidosis after cotreatment by flucloxacillin and paracetamol]

We report on the case of a 73-year-old man, who was referred to our emergency department for confusion and dyspnea. He had been under a treatment of flucloxacillin for six weeks because of a possible methicillin-susceptible Staphylococcus aureus (MSSA) endocarditis that was complicated by an acute late infection of a knee prosthesis. The laboratory work-up revealed a metabolic acidosis with a high anion gap. After exclusion of the other explanations, we retained a pyroglutamic metabolic acidosis due to concomitant intake of paracetamol and flucloxacillin, favoured by several risk factors. This diagnosis was confirmed by an organic acid dosage in the urine. After discontinuation of the drugs and a treatment with N-acetylcysteine, the evolution was favourable with correction of the metabolic acidosis and the confusional state.

Antibiotic regimens for late-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units, and observational studies in high-income countries suggest that 83% to 94% of newborns treated with antibiotics for suspected sepsis have negative blood cultures. The last Cochrane Review was updated in 2005. There is a need for an updated systematic review assessing the effects of different antibiotic regimens for late-onset neonatal sepsis.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for late-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2021, Issue 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for late-onset neonatal sepsis. We included participants older than 72 hours of life at randomisation, suspected or diagnosed with neonatal sepsis, meningitis, osteomyelitis, endocarditis, or necrotising enterocolitis. We excluded trials that assessed treatment of fungal infections.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (580 participants). All trials were at high risk of bias, and had very low-certainty evidence. The five included trials assessed five different comparisons of antibiotics. We did not conduct a meta-analysis due to lack of relevant data. Of the five included trials one trial compared cefazolin plus amikacin with vancomycin plus amikacin; one trial compared ticarcillin plus clavulanic acid with flucloxacillin plus gentamicin; one trial compared cloxacillin plus amikacin with cefotaxime plus gentamicin; one trial compared meropenem with standard care (ampicillin plus gentamicin or cefotaxime plus gentamicin); and one trial compared vancomycin plus gentamicin with vancomycin plus aztreonam. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. RCTs assessing different antibiotic regimens in late-onset neonatal sepsis with low risks of bias are warranted.

An Under-Recognised Cause of Iatrogenic, Severe Metabolic Acidosis

Case Pyroglutamic acidosis is an uncommonly diagnosed but important cause of a high anion gap metabolic acidosis. Our case report concerns an elderly male admitted to the Intensive Care Unit (ICU) following the acute onset of coma which developed during treatment of a prosthetic joint infection. A diagnosis of pyroglutamic acidosis was ultimately made and later confirmed with laboratory testing. Blood gas analysis revealed a profound high anion gap metabolic acidosis. Treatment Treatment included withdrawal of the precipitating medications, N-acetylcysteine and sodium bicarbonate. Discussion This case highlights an unusual cause of severe metabolic acidosis caused by commonly used medications and readily reversible if recognised. This is of particular relevance in elderly, frail patients as incorrect alternate diagnoses may result in decisions which incorrectly limit critical care therapies.

Lesson of the month 1: A rare adverse reaction between flucloxacillin and paracetamol

Flucloxacillin, a beta-lactam antibiotic, is a commonly prescribed antibiotic for the treatment of infections caused by staphylococci and streptococci, most notably Staphylococcus aureus Paracetamol is one of the most dispensed medications by NHS England and is used for the treatment of fever and pain.1 However most doctors are unaware that concurrent use of these drugs can cause a potentially fatal drug interaction due to pyroglutamic acidosis (PGA), also known as 5-oxoprolinaemia. PGA is a rare cause of raised anion gap metabolic acidosis due to disruption of the γ-glutamyl cycle. We report the case of a patient with multiple comorbidities who developed PGA due to coadministration of paracetamol and flucloxacillin.

Metabolic acidosis caused by concomitant use of paracetamol (acetaminophen) and flucloxacillin? A case report and a retrospective study

PURPOSE

A patient was identified with severe metabolic acidosis, a high anion gap and 5-oxoproline accumulation, probably caused by the simultaneous use of paracetamol (acetaminophen) and flucloxacillin. We wanted to investigate the necessity to control the interaction between both drugs with an automatic alert system.

METHODS

To investigate the relevance of the interaction of paracetamol and flucloxacillin, a retrospective study was conducted. Data on paracetamol and flucloxacillin prescriptions and laboratory data (pH, Na⁺, HCO₃^-, Cl^-, albumin and 5-oxoproline levels) were combined to assess the prevalence of acidosis, calculate the anion gap and analyse 5-oxoproline levels in clinically admitted patients using both drugs simultaneously.

RESULTS

In the 2-year study period, approximately 53,000 admissions took place in our hospital. One thousand and fifty-seven patients used paracetamol and flucloxacillin simultaneously, of which 51 patients (4.8%) had a serum pH ≤ 7.35. One patient, the same patient as presented in the case report, had a high anion gap and a toxic level of 5-oxoproline.

CONCLUSION

The prevalence of metabolic acidosis is very low and the only patient identified with the interaction was recognised during normal clinical care. We conclude that automatic alerts based on simultaneous use of paracetamol and flucloxacillin will generate too many signals. To recognise patients earlier and prevent severe outcomes, a warning system (clinical rule) based on paracetamol, flucloxacillin and pH measurement may be helpful. Early calculation of the anion gap can narrow the differential diagnosis of patients with metabolic acidosis and measurement of 5-oxoproline can explain acidosis due the interaction of paracetamol and flucloxacillin.

Pyroglutamic acid-induced metabolic acidosis: a case report

High anion gap metabolic acidosis due to pyroglutamic acid (5-oxoproline) is a rare complication of acetaminophen treatment (which depletes glutathione stores) and is often associated with clinically moderate to severe encephalopathy. Acquired 5-oxoprolinase deficiency (penicillins) or the presence of other risk factors of glutathione depletion such as malnutrition or sepsis seems to be necessary for symptoms development. We report the case of a 55-year-old women who developed a symptomatic overproduction of 5-oxoproline during flucloxacillin treatment for severe sepsis while receiving acetaminophen for fever control. Hemodialysis accelerated the clearance of the accumulated organic acid, and was followed by a sustained clinical improvement.

[Convulsions due to an interaction between anti-epileptic drugs and rifampicin]

BACKGROUND

Anti-epileptic drugs (AEDs) have a small therapeutic window, so it is important to monitor plasma levels. Inadequate plasma levels may lead to convulsions. Many AEDs are cleared hepatically, and there are many drug interactions that are known to lead to changes in plasma levels.

CASE DESCRIPTION

A 54-year-old woman with known epilepsy developed convulsions after using rifampicin and flucloxacillin, despite the use of maintenance treatment in the form of carbamazepine, valproic acid and clonazepam. Since rifampicin is known to induce several cytochrome P450 enzymes and clearance of the anti-epileptic drug used may be affected by this, it can be assumed that the convulsions were caused by rifampicin. This interaction is however not mentioned in the Dutch 'G-standard' database.

CONCLUSION

Rifampicin is known to be a strong inducer of various cytochrome P450 enzymes. This case description shows that the use of rifampicin may lead to convulsions. For this reason, these interactions should be included in the Dutch G-standard database.

Pyroglutamic aciduria: a cause of high anion-gap metabolic acidosis associated with common drugs

Pyroglutamic aciduria is a rare and probably under-recognised cause of metabolic acidosis which may be precipitated by certain common drugs.

[Peripheral intravenous catheter-related phlebitis]

Phlebitis is a very common complication of the use of intravenous catheters. Two patients with an i.v. catheter complicated by thrombophlebitis are described. Patient A was immunocompromised due to chronic lymphatic leukaemia and developed septic thrombophlebitis with positive blood cultures for S. Aureus. Patient B was being treated with flucloxacillin because of an S. Aureus infection and developed chemical phlebitis. Septic phlebitis is rare, but potentially serious. Chemical or mechanical types of thrombophlebitis are usually less severe, but happen very frequently. Risk factors include: female sex, previous episode of phlebitis, insertion at (ventral) forearm, emergency placement and administration of antibiotics. Until recently, routine replacement of peripheral intravenous catheters after 72-96 h was recommended, but randomised controlled trials have not shown any benefit of this routine. A recent Cochrane Review recommends replacement of peripheral intravenous catheters when clinically indicated only.

Flucloxacillin induced acute renal failure

BACKGROUND

Acute interstitial nephritis is a less frequently reported adverse effect of flucloxacillin compared with other well known associations such as hepatotoxicity.

OBJECTIVE

This article describes the conservative management of a case of flucloxacillin induced acute renal failure, and reviews the available evidence on the treatment of drug induced acute interstitial nephritis, including the use of corticosteroids.

DISCUSSION

Drug induced acute interstitial nephritis can be managed conservatively by cessation of the suspected offending drug in many cases. Referral should be made to a nephrologist, with consideration given to renal biopsy, followed by trial of corticosteroids, if renal function does not improve within 7 days of drug cessation.

Using a medical emergency team to manage anaphylactic shock

A case of presumed anaphylactic shock highlights early detection and review, rapid mobilization of the effector arm, and identification of implications for quality improvement.

Guilty as charged: unmeasured urinary anions in a case of pyroglutamic acidosis

A patient developed an unexplained metabolic acidosis with the characteristics of renal tubular acidosis. By correcting the serum anion gap for hypoalbuminaemia and analysing the urinary anions and cations, the presence of unmeasured anions was revealed. The diagnosis of pyroglutamic acidosis, caused by a combination of flucloxacillin and acetaminophen, was established. Strategies for solving complex cases of metabolic acidosis are discussed.

Antibiotic therapy: a major cause of drug-induced jaundice in southwest England

OBJECTIVE

To determine the incidence and causes of drug-induced jaundice in a rural community.

METHODS

A retrospective analysis of 800 patients presenting to a single-centre jaundice referral system serving a community of 400 000 over a period of 66 months (1998-2004). Standard criteria for drug-induced liver injury were applied to patients with a putative diagnosis of drug-induced jaundice. The incidence rates per prescription of drug-induced jaundice caused by co-amoxiclav and flucloxacillin were derived from local and national annual prescription rates.

RESULTS

The incidence of drug-induced jaundice was 1.27 (confidence limits 0.85-1.8) per 100 000 per annum in a total of 28 patients (17 men, mean age 69 years). Antibiotics were the commonest cause of jaundice (n=21). Of these, co-amoxiclav (n=9) and flucloxacillin (n=7) caused the majority with an incidence rate per 100 000 prescriptions of 9.91 (4.6-18.0) and 3.60 (1.5-7.2), respectively. Co-amoxiclav-induced jaundice was observed more commonly in elderly males (age 65 years, M : F 7 : 2). In those patients with flucloxacillin or co-amoxiclav-induced jaundice, bilirubin ranged from 54 to 599 mumol/l (267 mumol/l) with a resolution of jaundice between 30 and 90 days. Counselling with regard to potential drug-induced liver injury and reporting of the adverse reaction had been performed in 1/28 patients.

CONCLUSIONS

8.1% patients with no biliary obstruction and jaundice had a drug-induced and predominantly antibiotic-related aetiology particularly affecting an elderly population. We recommend that all patients receiving co-amoxiclav and flucloxacillin should be counselled before the therapy regarding the potential risk of jaundice and that an alternative antibiotic to co-amoxiclav is used if possible in men over the age of 60 years.

An unusual cause of severe metabolic acidosis

A 50-year-old man was transferred to the intensive care unit with high anion gap metabolic acidosis. Investigations suggested a diagnosis of pyroglutamic acidaemia. Factors contributing to the acidosis were medications (paracetamol and flucloxacillin), sepsis and renal failure. The acidosis resolved with supportive therapy and withdrawal of the drugs. It is important to recognise this treatable aetiology of metabolic acidosis.

Involvement of drug-specific T cells in acute drug-induced interstitial nephritis

Drug-induced interstitial nephritis can be caused by a plethora of drugs and is characterized by a sudden impairment of renal function, mild proteinuria, and sterile pyuria. For investigation of the possible pathomechanism of this disease, drug-specific T cells were analyzed, their function was characterized, and these in vitro findings were correlated to histopathologic changes that were observed in kidney biopsy specimens. Peripheral blood mononuclear cells from three patients showed a proliferative response to only one of the administered drugs, namely flucloxacillin, penicillin G, and disulfiram, respectively. The in vitro analysis of the flucloxacillin-reactive cells showed an oligoclonal immune response with an outgrowth of T cells bearing the T cell receptor Vbeta9 and Vbeta21.3. Moreover, flucloxacillin-specific T cell clones could be generated from peripheral blood, they expressed CD4 and the alphabeta-T cell receptor, and showed a heterogeneous cytokine secretion pattern with no clear commitment to either a Th1- or Th2-type response. The immunohistochemistry of kidney biopsies of these patients revealed cell infiltrations that consisted mostly of T cells (CD4+ and/or CD8+). An augmented presence of IL-5, eosinophils, neutrophils, CD68+ cells, and IL-12 was observed. In agreement with negative cytotoxicity assays, no cytotoxicity-related molecules such as Fas and perforin were detected by immunohistochemistry. The data indicate that drug-specific T cells are activated locally and orchestrate a local inflammation via secretion of various cytokines, the type of which depends on the cytokine pattern secreted and which probably is responsible for the renal damage.

Immunochemical detection of flucloxacillin adduct formation in livers of treated rats

Flucloxacillin is a semi-synthetic penicillin widely used in the prophylaxis and treatment of staphylococcal infections. Severe liver reactions, characterised by delayed cholestatic hepatitis and a prolonged course of recovery, are associated with flucloxacillin therapy. Clinical findings are suggestive of an immune mediated reaction but there exists little supporting experimental evidence. The formation of drug modified hepatic protein adducts has been proposed to play an important role in the hepatotoxicity of many drugs. The aim of the present study was to investigate whether flucloxacillin treatment results in adduct formation in vivo. Flucloxacillin was conjugated to rabbit serum albumin by formation of a penicilloyl determinant and used as an immunogen to raise a polyclonal antiserum specific for flucloxacillin-modified proteins. Antibody specificity was confirmed by competitive enzyme-linked immunosorbent assay (ELISA) with free drug. The antiserum was used in combination with western blotting to detect adduct formation in the livers of flucloxacillin treated rats. Western blot analysis of rat liver subcellular fractions revealed the formation of six flucloxacillin adducts in various subcellular fractions. These studies demonstrate for the first time that treatment with flucloxacillin results in the formation of hepatic protein adducts.

Risk of cholestatic liver disease associated with flucloxacillin and flucloxacillin prescribing habits in the UK: cohort study using data from the UK General Practice Research Database

AIMS

To provide additional quantification of the risk of flucloxacillin-related liver disease and to describe time trends in flucloxacillin prescribing in the UK.

METHODS

This was a cohort study using data from the UK General Practice Research Database. We identified patients with a first-time prescription for flucloxacillin or, for comparison, oxytetracycline from 1992 to 2002 and cases who developed clinically documented cholestatic liver disease of uncertain origin after first-time use of these drugs. We also determined the annual frequency of first-time use of flucloxacillin from 1991 to 2000.

RESULTS

We identified 283 097 and 131 189 first-time users of flucloxacillin and oxytetracycline, respectively. The risk of cholestatic liver disease per 100 000 first-time users was 8.5 (95% CI 5.4, 12.6) in the 1-45 days and 1.8 (95% CI 0.6, 4.1) in the 46-90 days after starting flucloxacillin, and 0.8 (95% CI 0.02, 4.3) in the 1-45 days after starting oxytetracycline. The frequency of first-time use of flucloxacillin remained stable between 1991 and 2000.

CONCLUSIONS

Flucloxacillin is now established as an important cause of cholestatic liver disease. Warnings about the risk have not had an impact on prescribing practices in the UK, where it remains the predominantly prescribed antistaphylococcal oral antibiotic. This situation in the UK is in sharp contrast to regulatory actions and changes in prescribing habits in Australia after identification of the risk of cholestasis associated with flucloxacillin, and to the predominant use of the alternative drug dicloxacillin in the USA.

Fulminant drug-induced hepatic failure leading to death or liver transplantation in Sweden

OBJECTIVE

There are only a few data on the prevalence of drug-induced liver injury associated with fatal outcome. The aim of this study was to determine the nature and number of suspected adverse drug-induced liver disease associated with fatalities and/or liver transplantation since reporting of adverse drug reactions (ADRs) started in Sweden.

MATERIAL AND METHODS

All reports of suspected hepatic ADRs with fatal outcome received by the Swedish Adverse Drug Reactions Advisory Committee (SADRAC) from 1966 to 2002 were reviewed and causality assessed.

RESULTS

The SADRAC received 151 reports of suspected ADRs with fatal outcome from liver injury; 48 cases were either unlikely or excluded. Of the remaining 103 cases, 13 (13%) were highly probable, 48 (47%) probable and 42 (41%) possible. The median age of the 103 patients was 64 years (47-77 interquartile range (IQR)) and 59 (57%) were males. The majority of cases were classified as hepatocellular (75%), with only 15% cholestatic and 10% mixed. Halothane, paracetamol, flucloxacillin, sulfamethoxazole/trimethoprim and diclofenac were the most common drugs associated with fatal outcome. Seventeen patients underwent liver transplantation, most commonly because of paracetamol and disulfiram toxicity.

CONCLUSIONS

A wide range of suspected ADRs are associated with fatalities. Antibiotics and analgesics are associated with the greatest number of reports of deaths.

Examination of stability and compatibility of flucloxacillin (Floxapen®) and ceftazidime (Fortum®) in two infusion media: relevance for the clinical praxis

Flucloxacillin (Floxapen) and ceftazidime (Ceftazidim) are both highly active antibiotics against Gram-positive and Gram-negative organisms, respectively. Because of their complementary spectra of activity, simultaneous administration of both drugs via continuous infusion is highly favored by clinicians. Therefore, the aim of the present study was to examine the stability and compatibility of both drugs in Aqua ad injections and in physiological solution of sodium chloride in the presence and absence of furosemide (Lasix). Physical and chemical stability were examined using different concentrations of flucloxacillin (2-12 g/50 ml) and ceftazidime (2-9 g/50 ml). On the basis of a limit of max. 10% degradation, flucloxacillin and ceftazidime can be considered stable at 4 degrees C and room temperature for up to 24 hours. Neither concentration nor infusion medium had significant influence on the degradation of both compounds. Addition of furosemide (250 mg/50 ml) does not cause any incompatibilities or significant decrease of the antimicrobial drug concentrations.

Flucloxacillin-induced aplastic anaemia and liver failure

Flucloxacillin is a commonly prescribed semisynthetic penicillinase-resistant penicillin primarily used for the treatment of cutaneous staphylococcal infections. It is well-recognized that flucloxacillin may occasionally result in fatal hepatic injury. We report the case of a 40-year-old woman who developed fulminant hepatic failure and aplastic anaemia following a course of oral flucloxacillin. At the time of transplantation the patient was severely neutropenic. Post-transplant, the patient received single donor leucocyte transfusions, which resulted in a dramatic increase in neutrophil count. The patient was discharged from hospital after 120 days with normal liver function and recovered bone marrow. In this report, we discuss the care of patients with aplastic anaemia in the peritransplant setting.

Flucloxacillin associated neutropenia in children treated for bone and joint infections

OBJECTIVE

This report describes episodes of acute neutropenia associated with flucloxacillin use in children treated for bone and joint infections.

METHODS

A retrospective chart audit was performed on eight children who developed neutropenia when treated with flucloxacillin.

RESULTS

Eight children (aged 1 month to 13 years) had a diagnosis of neutropenia attributed to treatment with flucloxacillin, seven of whom received parenteral therapy. The time to onset of neutropenia averaged 27 days, with neutrophil counts returning to normal limits in all patients after 2 to 9 days. Two children were asymptomatic when the neutropenia was detected. The average flucloxacillin dose used was 65% (range 20-100%) of the recommended maximum dose.

CONCLUSIONS

These cases suggest that flucloxacillin should be used with greater caution and guidelines for dosing and clinical monitoring (regular neutrophil counts) need to be reassessed, despite none of these patients experiencing serious sequelae.

A Randomized Clinical Trial to Compare Fleroxacin-Rifampicin with Flucloxacillin or Vancomycin for the Treatment of Staphylococcal Infection

BACKGROUND

Oral combination therapy with fluoroquinolones plus rifampicin is a promising alternative to standard parenteral therapy for staphylococcal infections.

METHODS

In a multicenter, randomized trial, we compared the efficacy, safety, and length of hospital stay for patients with staphylococcal infections treated either with an oral combination of a fluoroquinolone (fleroxacin) plus rifampicin or with standard parenteral treatment (flucloxacillin or vancomycin). Patients were included if cultures showed the presence of bacteremia or deep-seated infections with Staphylococcus aureus (104 patients) or catheter-related bacteremia due to drug-susceptible, coagulase-negative staphylococci (23 patients).

RESULTS

The cure rate in the intention-to-treat analysis was 78% for the fleroxacin-rifampicin group (68 patients) and 75% for the standard therapy group (59 patients; 47 received flucloxacillin, and 12 received vancomycin); in the population of clinically evaluable patients (n=119), the cure rate was 82% and 80%, respectively; and in the population of microbiologically evaluable patients (n=103), the cure rate was 86% and 84%, respectively. Clinical and bacteriological failures after S. aureus infections were documented in similar proportions of patients. The median length of hospital stay after study entry was 12 days in the fleroxacin-rifampicin group, compared with 23 days in the standard treatment group (P=.006). More adverse events probably related to the study drug were reported in the fleroxacin-rifampicin group than in the standard therapy group (15 of 68 vs. 5 of 59 patients; P=.05).

CONCLUSIONS

This study suggests that an oral regimen containing a fluoroquinolone plus rifampicin may be effective for treating staphylococcal infections, allowing earlier discharge from the hospital.

Indirect cytotoxicity of flucloxacillin toward human biliary epithelium via metabolite formation in hepatocytes

Flucloxacillin, an isoxazolyl-penicillin, causes cholestasis and biliary epithelium injury. The aim of the study was to determine whether flucloxacillin, either directly or through metabolite formation, may induce cytotoxicity in hepatic or biliary cells. Cytotoxicity was assessed by lactate dehydrogenase release in primary cultures of human hepatocytes and of gallbladder-derived biliary epithelial cells (BEC). Metabolite production in microsome and cell preparations was analyzed by chromatography, nuclear magnetic resonance spectroscopy, and mass spectrometry. While flucloxacillin induced no direct cytotoxicity in any of the hepatocyte (n = 12) and BEC (n = 19) preparations, the conditioned media from cultured hepatocytes preincubated with flucloxacillin (50-500 mg/L) triggered a significant increase in lactate dehydrogenase release over controls in approximately 50% of BEC preparations (7/12), and this effect depended upon flucloxacillin concentration. Remaining BEC preparations exhibited no toxic response. Cytotoxicity in BEC preparations (9/13) was also induced by the supernatants of human liver microsomes and of recombinant human cytochrome P450 (CYP)3A4 preincubated with flucloxacillin (500 mg/L). Supernatants from both liver microsome and CYP3A4 preparations contained one major metabolite which was identified as 5'-hydroxymethylflucloxacillin. The production of this metabolite was inhibited following CYP3A4 inhibition by troleandomycin in human liver microsomes, and markedly enhanced following CYP3A induction by dexamethasone in rat liver microsomes. As opposed to BEC, cultured hepatocytes displayed significant CYP3A activity and produced low amounts of this metabolite. The purified metabolite (0.01-5 mg/L) exerted toxic effects in BEC but not in hepatocytes. In conclusion, hepatocytes mainly via CYP3A4 activity, generate flucloxacillin metabolite(s) including 5'-hydroxymethylflucloxacillin that may induce cytotoxicity in susceptible BEC. These metabolic events may contribute to the pathogenesis of drug-induced cholangiopathies.

Anaphylaxis and monoamine oxidase inhibitors--the use of adrenaline

A 67 year old woman taking a monoamine oxidase inhibitor (MAOI) presented to the accident and emergency department with an anaphylactic reaction to flucloxacillin. This case highlights the uncertainty regarding the use of adrenaline (epinephrine) in the context of concurrent MAOI use. A summary of the evidence is presented to clarify this.

A pseudolymphomatous skin reaction secondary to flucloxacillin

We report the first case of a pseudolymphomatous skin reaction precipitated by flucloxacillin. Skin histology was suggestive of a cutaneous lymphoma, and DNA analysis by single stranded conformational polymorphism (SSCP) demonstrated T-cell receptor gamma gene monoclonality. Withdrawal of flucloxacillin led to immediate clinical improvement and gradual resolution of skin rash and lymph nodes.

Hepatitis from 5-methoxypsoralen occurring in a patient with previous flucloxacillin hepatitis

A 55-year-old woman with psoriasis vulgaris was treated with oral 5-methoxypsoralen and UVA photochemotherapy. After 40 treatments over 3 months she became unwell with hepatitis attributable to the psoralen. Six years earlier she developed cholestatic hepatitis to flucloxacillin. A previous history of drug-induced reactions should be sought before prescribing further drugs with similar adverse effects.

Postmarketing surveillance: strengths and limitations. The flucloxacillin-dicloxacillin story

Spontaneous reporting of adverse drug reactions continues to be the principal method used for monitoring the safety of marketed drugs. Despite the many successes attributed to these schemes, they can reliably detect only a small fraction of the range of possible drug-related events and provide virtually no useful quantitative data. Some of the limitations of spontaneous reporting were demonstrated recently in relation to flucloxacillin. Reports in Australia suggested the likelihood of an unacceptable risk of flucloxacillin-associated jaundice, but the data from spontaneous reporting in countries with apparently similar use of the drug, such as New Zealand and the UK, were insufficient to confirm or refute this proposition. Spontaneous monitoring should be supplemented by the systematic monitoring of cohorts of users of new drugs, using record-linkage to track their subsequent health. Although several impediments exist to the introduction of such a scheme in Australia, consideration should be given to addressing how such a system might be implemented.

Improving drug use: a case study of events which led to changes in use of flucloxacillin in Australia

Policy makers and health professionals charged with implementing policies to improve medication use require knowledge as to how to integrate and co-ordinate strategies and interventions which have been shown to be effective. Experimental methodologies are commonly used to assess the effectiveness of interventions to improve medication use and while valuable for determining the effectiveness of particular interventions, they do not add to our understanding of how to co-ordinate and integrate multiple initiatives to improve medication use. We argue that analyses of the overall system of events which are implemented to improve medication use are also needed. In this paper, we demonstrate how the case study analysed within the framework of the Transtheoretical Model of behaviour change can be used to provide an understanding of the relationship of events which result in changes in medication use. A case study of the sequence of events which led to changes in the utilisation of flucloxacillin in Australia is assessed. The analysis demonstrated that the effectiveness of individual interventions was dependent upon the initiatives which were implemented concurrently and those that had been implemented previously. Changes in the utilisation of flucloxacillin resulted from regulatory interventions and the promotion of appropriate alternative therapies. The effectiveness of this change was enhanced by previous interventions which had raised awareness amongst health professionals of the adverse hepatic reaction associated with the use of flucloxacillin. This methodology adds to those currently employed to study methods of improving use of medications. It provides an understanding of the role of each initiative in the overall system. This is valuable for policy makers, providing them with information on how to co-ordinate and orchestrate the myriad of activities which support quality use of medicines.

Oral manifestations of toxic epidermal necrolysis (TEN) in patients with AIDS: report of five cases

OBJECTIVE

To describe oral findings in HIV-infected individuals with toxic epidermal necrolysis (TEN).

PATIENTS

In a retrospective study over a 10 year period the medical histories of 931 hospitalised HIV-infected patients were reviewed for the occurrence of TEN.

RESULTS

Five cases of TEN were diagnosed (three men, two women; median age: 41 years; median CD4+ T lymphocyte count: 20/microliter). Four patients had been treated with biweekly pyrimethamine/sulfadoxine for prophylaxis against Pneumocystis carinii pneumonia and toxoplasmosis. In one patient flucloxacillin was administered. Signs of TEN with cutaneous epidermolysis occurred and patients showed oral lesions characterized as oropharyngeal blisters and bullae on the palate, buccal mucosa, tongue and floor of the mouth initially. Antibiotics and corticosteroids were administered; none of the patients died.

CONCLUSION

Longacting sulfonamides and antibiotics have been implicated as the cause of severe mucocutaneous reactions. Since rash and oral blisters may be the first signs of TEN in patients receiving these it is mandatory to follow up these patients closely to detect oral or cutaneous changes indicating the development of TEN.

Transient 5-oxoprolinuria (pyroglutamic aciduria) with systemic acidosis in an adult receiving antibiotic therapy

5-Oxoprolinuria is a recognized condition with increased urinary excretion of 5-oxoproline and is associated with a variety of inborn metabolic defects involving the series of enzyme-linked reactions known as the gamma-glutamyl cycle. We report the unusual case of a 35-year-old woman who initially presented with staphylococcal pneumonia but went on to develop a transient high anion gap metabolic acidosis. The development and subsequent complete recovery from this acidosis were subsequently shown to be related in time to the intravenous administration of the antibiotics flucloxacillin and netilmicin. Analysis of the patient's urine for organic acids revealed massively increased excretions of 5-oxoproline at the peak of her acidosis. We suggest that this patient developed a transient disturbance in the gamma-glutamyl cycle involving the 5-oxoprolinase step, which resulted in accumulation of 5-oxoproline that caused a severe high anion gap metabolic acidosis. The administered antibiotics remain as possible causative agents.

Drug-induced hepatic injury

Drugs and other chemical toxins account for less than 5% of cases of jaundice or acute hepatitis and fewer cases of chronic liver disease, but they are an important cause of more severe types of hepatic injury. Drug reactions produce an array of hepatic lesions that mimic all known hepatobiliary diseases; this poses a diagnostic challenge for physicians and pathologists. Diagnosis of drug-induced hepatic injury is circumstantial, with positive rechallenge being the only factor that unequivocally implicates a particular agent. Nonetheless, other aspects of the temporal relationship between drug ingestion and adverse reaction, exclusion of other diseases, the presence of extrahepatic features of drug hypersensitivity and some findings on liver biopsy can lend support to the diagnosis. Some of these issues will be explored in this review by considering contemporary paradigms of drug-induced hepatic injury. Factors that predispose to dose-dependent hepatic injury will be considered in relation to acetaminophen, an example of acute hepatotoxicity, and methotrexate, an agent that can produce hepatic fibrosis. Flucloxacillin will be discussed as an example of drug-induced cholestatic hepatitis often associated with prolonged cholestasis and the vanishing bile duct syndrome. Minocycline and diclofenac will be mentioned as two drugs for which drug hepatitis is an exceedingly rare complication. Finally, the evidence that Chinese herbal medicines can be hepatotoxic will be reviewed.

A jaundiced farmer

A previously well farmer became deeply jaundiced after dipping sheep with organophosphate sheep dips. He had failed to wear adequate protective clothing and presumably absorbed toxic compounds through his skin. There is currently major interest in these compounds because of their protean clinical manifestations.

Drug associated hepatic reactions in New Zealand: 21 years experience

AIMS

To review spontaneous reports of drug-associated adverse hepatic reactions.

METHODS

Reports of drug-associated adverse hepatic reactions received by the New Zealand Centre for Adverse Reactions Monitoring over the 21 year period January 1974 to December 1994 were reviewed. Subdivision into three 7 year periods was undertaken to compare patterns.

RESULTS

Of a total of 22,455 adverse medicine reaction (AMR) reports there were 943 reports of liver injury (4.2%). Two hundred and five drugs were associated with hepatic reactions. The top 20 drugs accounted for 57% of all liver reactions. Fifty-seven percent were reported in females. Hepatotoxicity was most commonly reported among patients 50-80 years old. Liver reactions were associated with a 3.3% mortality, but were responsible for 7.4% of all fatal occurrences. There was a steady increase in the number of reports over the 21 years. Although the largest number of reports of liver injury were received between 1988 and 1994, mortality was lowest during this period. There were substantial differences in the medicines associated with hepatic reactions during each of the three periods, although erythromycin was the commonest cause throughout. Erythromycin was associated with two deaths. Halothane and perhexilene were the most frequent cause of death and were two of the most important causes of liver injury during the first and second periods. Diclofenac, Augmentin and flucloxacillin were important causes of hepatotoxicity during period 3 but were not associated with a fatal outcome.

CONCLUSION

Hepatic reactions accounted for 4.2% of all adverse medicine reactions and 7.4% of all fatal occurrences. The top 20 drugs were responsible for 57% of all liver reactions. Despite a steady increase in the number of reports during the 21 years, mortality was lowest during the last 7 years. Differences in the medicines causing liver injury during the three periods influenced the number of fatalities. Erythromycin was the most commonly reported cause of hepatic reactions but was usually associated with a favourable outcome. There were no reported deaths with diclofenac, Augmentin or flucloxacillin.

Flucloxacillin associated cholestatic hepatitis. An Australian and Swedish epidemic?

The clinico-pathological entity of flucloxacillin-associated cholestatic hepatitis is described and the recognition and documentation of cholestasis associated with flucloxacillin and with related isoxazolyl-penicillins (cloxacillin, dicloxacillin) is examined on an international basis, with particular reference to Australia. Data were obtained from the literature, from the Australian adverse drug reaction monitoring agency and from the Collaborative Centre for International Drug Monitoring (World Health Organisation) in Sweden. Approximately 600 cases of flucloxacillin-associated cholestatic hepatitis were collected, as well as 164 cases associated with other isoxazolyl penicillins. Jaundice and pruritus may first appear several weeks after administration of the drug has ceased and typically are severe and protracted. Liver tests may be abnormal for months after symptomatic recovery. Death is uncommon. Liver pathology shows centrizonal bile stasis with portal tract inflammation and variable loss of bile ducts. Approximately 1 in 15,000 users of flucloxacillin will develop the reaction. Increasing age (> 55 years) and prolonged intake (> 14 days) are particular risk factors. Cholestasis associated with cloxacillin/dicloxacillin appears to be similar in nature but is less well defined. Recognition and reporting of the reaction have been uncommon in the United Kingdom inter alia and high in Sweden and Australia, although estimates of risk have been similar. In Australia, the remarkably high rate of reports appears to be the result of sustained publicity for the reaction. There is only a trickle of reports of cholestatic hepatitis in association with the use of cloxacillin and dicloxacillin from the USA and Canada. The high level of awareness of the reaction and consequential regulatory action so far have not resulted in a diminution of its occurrence in Australia.

Serum sickness like illness and antimicrobials in children

AIM

To determine which antimicrobials are associated with the development of serum sickness like reactions in children admitted to hospital in Christchurch.

METHOD

A retrospective case note review of children admitted with serum sickness like reactions over a 10 year period was carried out. 59 children were identified and 30 of these were eligible for inclusion in the study.

RESULTS

Of the 30 children with serum sickness like reaction, 19 had received cefaclor alone, six penicillin V, two amoxycillin, and one each flucloxacillin cotrimoxazole and triacetylolendomycin (TAO). Children received these antimicrobials for 3-10 days.

CONCLUSION

In this study cefaclor was commonest antimicrobial agent associated with the development of serum sickness like reaction. This association should receive consideration prior to prescribing cefaclor to children.