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.