Penicillin encephalopathy

Development and validation of a dosing nomogram for continuous infusion cloxacillin in infective endocarditis

BACKGROUND

Cloxacillin is the first-line treatment for methicillin-susceptible staphylococcal infective endocarditis (IE). The recommended dose is 12 g per day regardless of the patient characteristics, despite the importance of renal function on its pharmacokinetics.

OBJECTIVES

We sought to build a population pharmacokinetics model of continuous infusion cloxacillin in IE patients to evaluate the influence of multiple covariates and then develop a nomogram based on significant covariates for individual adaptation.

PATIENTS AND METHODS

We included patients of a local IE cohort who were treated with cloxacillin administered by continuous infusion, excluding those who received intermittent or continuous dialysis, extracorporeal membrane oxygenation or extracorporeal circulation. The population pharmacokinetic analysis was performed using Pmetrics. The influence of weight, ideal weight, height, body mass index, body surface area, glomerular filtration rate (GFR) calculated with the Chronic Kidney Disease Epidemiology Collaboration formula (both expressed in mL/min/1.73 m² and in mL/min) and serum protein level on cloxacillin pharmacokinetics was assessed. Accounting for relevant covariates, a dosing nomogram was developed to determine the optimal daily dose required to achieve a steady-state plasma concentration range of 20-50 mg/L with a probability ≥0.9.

RESULTS

A total of 114 patients (331 plasma concentrations) were included. A one-compartment model including GFR expressed in mL/min as a covariate was chosen. Using the nomogram, achieving the cloxacillin concentration target requires a daily dose ranging from 3.5 to 13.1 g for a GFR ranging from 20 to 125 mL/min.

CONCLUSIONS

This work provided a practical tool for cloxacillin dose adjustment in IE according to renal function.

Responses to antibiotics in human iPSC-derived neurons based on the clinical antibiotic-associated encephalopathy classification

Antibiotic-associated encephalopathy (AAE) is a central nervous system disorder caused by antibiotics administration and classified into three types based on clinical symptoms. Type 1 AAE causes seizures and myoclonus, type 2 causes psychiatric symptoms, and type 3 is characterized by cerebellar ataxia. In this study, we investigated whether the electrical activity of in vitro human iPSC-derived neurons to antibiotics could be classified based on the 3 types of AAEs classified by clinical symptoms. Glutamatergic, GABAergic neurons and astrocytes differentiated from human iPS cells were seeded on micro-electrode array (MEA). The cumulative administration of 13 different antimicrobials detected changes in neural activity that differed according to AAE type. Next, we classified the antimicrobials by principal component analysis (PCA) and confirmed the AAE type of each agent. We found that Types 1-3 AAE agents were distributed separately. The classification of antibiotics depending on electrophysiological response characteristics was consistent with the clinical practice classification of AAEs. In conclusion, the combination of electrophysiological responses of human iPS cell-derived neural networks measured by MEA plus multivariate analysis methods will effectively detect and classify antibiotics developmental risks.

Neurological Adverse Effects Attributable to β-Lactam Antibiotics: A Literature Review

β-lactam antibiotics are commonly prescribed antibiotic drugs. To describe the clinical characteristics, risk markers and outcomes of β-lactam antibiotic-induced neurological adverse effects, we performed a general literature review to provide updated clinical data about the most used β-lactam antibiotics. For selected drugs in each class available in France (ticarcillin, piperacillin, temocillin, ceftazidime, cefepime, cefpirome, ceftaroline, ceftobiprole, ceftolozane, ertapenem and aztreonam), a systematic literature review was performed up to April 2016 via an electronic search on PubMed. Articles that reported original data, written in French, Spanish, Portuguese or English, with available individual data for patients with neurological symptoms (such as seizure, disturbed vigilance, confusional state, myoclonia, localising signs, and/or hallucinations) after the introduction of a β-lactam antibiotic were included. The neurological adverse effects of piperacillin and ertapenem are often described as seizures and hallucinations (>50 and 25% of cases, respectively). Antibiotic treatment is often adapted to renal function (>70%), and underlying brain abnormalities are seen in one in four to one in three cases. By contrast, the neurological adverse drug reactions of ceftazidime and cefepime often include abnormal movements but few hallucinations and seizures. These reactions are associated with renal insufficiency (>80%) and doses are rarely adapted to renal function. Otherwise, it appears that monobactams do not have serious neurological adverse drug reactions and that valproic acid and carbapenem combinations should be avoided. The onset of disturbed vigilance, myoclonus, and/or seizure in a patient taking β-lactam antibiotics, especially if associated with renal insufficiency or underlying brain abnormalities, should lead physicians to suspect adverse drug reactions and to consider changes in antibacterial therapy.

Prognosis of neurologic complications in critical illness

Neurologic complications of critical illness require extensive clinical and neurophysiologic evaluation to establish a reliable prognosis. Many sequelae of intensive care unit (ICU) treatment, such as delirium and ICU-acquired weakness, although highly associated with adverse outcomes, are less suitable for prognostication, but should rather prompt clinicians to seek previously unnoticed persisting underlying illnesses. Prognostication can be confounded by drug administration particularly because its clearance is abnormal in critical illness. Some neurological complications are severe, and can last for months or years after discharge from ICU. The most important ethical aspects regarding neurologic complications in critically ill patients are prevention, recognition, and identification, and prevention of self-fulfilling prophecies. This chapter summarizes the tool of prognostication of major neurological complications of critical illness.

Systematic overdosing of oxa- and cloxacillin in severe infections treated in ICU: risk factors and side effects

Background

Oxacillin and cloxacillin are the most frequently used penicillins for the treatment of severe methicillin-susceptible Staphylococcus aureus infections in intensive care units (ICUs), especially endocarditis. International recommendations do not suggest any adaptation of the dosage in case of renal impairment. We wanted to assess the risk factors for overdosing in ICU and the related observed side effects.

Methods

All patients with a therapeutic drug monitoring of oxa- or cloxacillin between 2008 and 2014 were included. The target range of trough concentration for total antibiotic activity was considered to be 20–50 mg/L. Data concerning the infection, the given treatment, the renal function, and the attributed side effects of overdosing were collected. A logistic regression model was used to compute the measured trough concentrations.

Results

Sixty-two patients were included in this study. We found a median trough plasma concentration of 134.3 mg/L (IQR 65.3–201 mg/L). Ten patients (16.1%) reached the target concentration; all other patients (83.9%) were overdosed. Eleven patients (17.7%) experienced neurological side effects attributed to a high antibiotic concentration, i.e. persistent coma and delirium. When adjusted on the dosage used, the risk of overdosing was significantly associated with a creatinine clearance <10 mL/min (with or without hemodialysis).

Conclusion

With the suggested dose of 12 g/day for cloxacillin treatment in case of endocarditis and severe infections occurring in ICU, 83.9% of patients are largely overdosed. Considering the observed side effects, doses should be accurately monitored and reduced, particularly when renal replacement therapy is needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0255-8) contains supplementary material, which is available to authorized users.

Cloxacillin-induced seizure in a hemodialysis patient

We are reporting a cloxacillin-induced seizure in a patient with stage 5 chronic kidney disease requiring hemodialysis. To our knowledge, there are no published case reports of seizures induced by parenteral cloxacillin in hemodialysis patients. A young hemodialysis female was admitted to the hospital with decreased level of consciousness. Blood cultures revealed methicillin-sensitive Staphylococcus aureus where cloxacillin 2 g intravenously every 4 hours was initiated. Head computed tomography (CT) was not significant. After 14 hours of cloxacillin therapy (4 doses), the patient demonstrated tonic/clonic seizure activity, where phenytoin and lorazepam were initiated. The anti-seizure medications partially reduced seizure activity. Once the cloxacillin was discontinued, the seizures stopped. Two weeks later, all anti-seizure medications were stopped with no further seizure activity. Cloxacillin elimination in hemodialysis patients is similar to patients with normal kidney function. Although cloxacillin does not significantly cross the blood-brain barrier, the correlation between the start of seizures and cloxacillin initiation was confirmed by the negative CT and blood chemistry laboratory results. Moreover, seizure activity was terminated upon discontinuation of cloxacillin. Although further investigation for the cause of such seizures is warranted, clinicians should use caution when giving high doses of cloxacillin in hemodialysis patients.

Antiinfective agents affecting cognition: a review

The adverse effects of antimicrobial, antiviral and anthelmintic agents on cognitive function have attracted substantial research interest in the last three decades. There are sporadic individual reports of negative effects on cognition by penicillin, amoxycillin, cloxacillin, cephalothin, cephazolin, cefuroxime, ceftazidime, tobramycin, doxycycline, chloramphenicol, lomefloxacin, pefloxacin, isoniazid, amphotericin B, acyclovir, chloroquine, clioquinol, metronidazole, sulfasalazine among other antimicrobial agents. Antimicrobial and antiprotozoal agents reported to affect consciousness in particular are amoxycillin, cloxacillin, ticarcillin, cephalothin, cephazolin, ceftazidime, cefuroxime, tobramycin, lomefloxacin, pefloxacin, amphotericin B, acyclovir, chloroquine, clioquinol, and metronidazole. The relationship between some other antimicrobial, antiviral and anthelmintic agents and cognition is yet to be clearly established due to the existence of controversial reports. Few antimicrobial, antiviral or anthelmintic agents have been found to be devoid of any effect on memory. A few others may enhance cognitive performance. This review focuses on this issue, summarizing the published clinical and experimental studies relevant to this area of research and discussing its clinical implications. Suggested mechanisms responsible for the adverse effects of different antimicrobial, antiviral, and anthelmintic agents on cognitive function are reported. Future recommendations point to immense research opportunities to investigate the cognitive profile of newly discovered antimicrobial agents.

Drug-induced myoclonus: frequency, mechanisms and management

Myoclonus is a sudden, abrupt, brief, 'shock-like' involuntary movement caused by muscular contractions ('positive myoclonus') or a sudden brief lapse of muscle contraction in active postural muscles ('negative myoclonus' or 'asterixis'). Various disorders can cause myoclonus including neurodegenerative and systemic metabolic disorders and CNS infections. In addition, myoclonus has been described as an adverse effect of some drugs. Level II evidence is available to indicate that levodopa, cyclic antidepressants and bismuth salts can cause myoclonus, while there is less robust evidence to associate numerous other drugs with the induction of myoclonus. The pharmacological mechanisms responsible for this adverse effect are not well established, although increased serotonergic transmission may be involved in the induction of myoclonus by several drugs. Drug-induced myoclonus usually resolves after withdrawal of the offending drug, but in some cases specific treatments are needed.

Drug-induced movement disorders

Parkinsonism, tremor, chorea-ballismus, dystonia, tardive dyskinesia, myoclonus, tics and akathisia can be induced by many drugs. The drugs that are most frequently implicated in movement disorders are antipsychotics, calcium antagonists, orthopramides and substituted benzamides (e.g. metoclopramide, sulpiride, clebopride, domperidone), CNS stimulants, antidepressants, anticonvulsants, antiparkinsonian drugs and lithium. It is possible for a single drug to induce 2 or more types of movement disorders in the same patient. Movement disorders are not always reversible after drug withdrawal.

Low neurotoxicity of LJC 10,627, a novel 1 beta-methyl carbapenem antibiotic: inhibition of gamma-aminobutyric acidA, benzodiazepine, and glycine receptor binding in relation to lack of central nervous system toxicity in rats

The toxicity of LJC 10,627 to the central nervous system of rats was evaluated by examining the effects of the compound on gamma-aminobutyric acidA, benzodiazepine, and glycine receptor binding in rat synaptic membranes and on the induction of behavioral convulsions by intraventricular administration to rats. The concentrations of this compound needed to inhibit specific [3H]muscimol binding, specific [3H]diazepam binding, and specific [3H]strychnine binding were greater than those of imipenem, as demonstrated by the 50% inhibitory concentrations (IC50S of LJC 10,627, greater than 10 mM for each; IC50S of imipenem, 0.6, 1.9, and 0.2 mM, respectively). These results reflect the fact that LJC 10,627 does not evoke severe convulsions or cause death, even when it is administered intraventricularly at a high dose (300 micrograms per rat), and suggest that the low neurotoxic potential of LJC 10,627 may be attributed to the chemical structure of this compound, which has a methyl radical at the 1 beta site and a triazolium radical at the side chain of the second site.

Penicillin-induced convulsions have preferential effects on transmitter glutamate pools in rat neostriatum

Convulsant doses of penicillin and elevated ambient pressure of 41 bar enhance the excitability of neurons. Their effects have been studied in neostriatal tissue with methods allowing differentiation between transmitter and metabolic glutamate pools. Levels of glutamate (Glu), glutamine (Gln), aspartate (Asp); gamma-aminobutyric acid and taurine were measured in the intact and decorticated neostriatum and parieto-occipital cortex of rats with a unilateral frontal cortex ablation. Intravenous infusion of penicillin at 1 bar decreased the neostriatal Glu content in the intact but not in the decorticated hemisphere. Pressure of 41 bar significantly decreased the level of Asp in the decorticated side only. Infusion of penicillin at 41 bar reduced the levels of Glu by 20.1% and Gln by 21.0% in the intact neostriatum only, whereas it decreased the Asp level in both sides as compared to control. The cortical Glu content was decreased only after infusion of penicillin at 41 bar. The results suggest that intravenous penicillin has a more pronounced effect on transmitter than on metabolic Glu pools in rat brain.

The effect of probenecid on the renal tubular excretion of benzylpenicillin

1 The aim of this study was to establish whether the renal tubular excretion of benzylpenicillin is saturable and whether the effect of probenecid on the tubular excretion of benzylpenicillin is dose-dependent. 2 Each of four volunteers underwent three experiments. In each experiment benzylpenicillin was administered by continuous infusion, such that three different consecutive concentration levels were reached. In the first experiment no probenecid was given; in the second and third experiments, probenecid was administered by continuous infusion at a low and higher rate, respectively. 3 Plasma and urinary concentrations of benzylpenicillin were determined at 30 min intervals by high performance liquid chromatography. 4 By fitting the equation Rtub = Rtub,max.Cp/(EC50 + Cp) to the values of the tubular excretion rate found for benzylpenicillin (Rtub) vs the free plasma concentration (Cp), the values of Rtub,max and EC50 could be calculated: 3350 (+/- 606) mg h-1 for Rtub,max and 48.0 (+/- 17.8) mg l-1 for EC50 (in the absence of probenecid). 5 The EC50 for benzylpenicillin increased significantly with increasing doses of probenecid. 6 The dose of probenecid at which 50% of the excretory system is occupied by probenecid in the absence of benzylpenicillin (ED50) ranged from 13.2 to 108.5 mg h-1. 7 The EC50 of probenecid in one subject could actually be measured: 52.3 mg l-1. 8 Extrapolating these results to the clinical situation, the commonly used daily dose of 2 g of probenecid is likely to be close to the maximal effective dose for inhibition of the tubular excretion of benzylpenicillin.

Staphylococcal septicaemia complicated by probable cloxacillin neurotoxicity and by jaundice induced by fusidic acid

Two weeks following a renal arteriogram a 56-year-old man with severe hypertension developed a staphylococcal septicaemia. After six weeks treatment with intravenous fusidic acid and cloxacillin he became icteric, confused and disorientated. The fusidic acid was stopped and the serum bilirubin fell to normal. His confusion persisted and serum cloxacillin levels were found to be grossly elevated. The patient's mental state returned to normal following withdrawal of cloxacillin. We attribute his jaundice to treatment with fusidic acid and his acute confusional state to cloxacillin neurotoxicity.

Cerebral toxicity of penicillins in relation to their hydrophobic character

The neurotoxic effects of ticarcillin, methicillin, phenthicillin, oxacillin, cloxacillin and dicloxacillin were studied in the conscious rabbit. During and after intravenous administration of 1.2 and 2.4 g/kg, resp., over 50 min the blood concentrations of the drugs were determined and the neurotoxicity assessed by continuous recording of the electroencephalogram. The hydrophobia of the penicillins was characterized by determination of their partition coefficients between isobutanol and buffer solution pH 7.4. The penicillins showed quite different neurotoxic properties. A close correlation (r = 0.928) was found between the neurotoxic potency of the penicillins and their partition coefficients. With increasing hydrophobia the neurotoxic potency increased in the following sequence: Ticarcillin, methicillin, oxacillin, phenethicillin, cloxacillin, dicloxacillin. It can be concluded, therefore, that determination of the partition coefficient of a penicillin gives valuable information on the neurotoxicity to be expected. The introduction of a neurotoxicity quotient revealed that penicillins may be divided into two groups: less neurotoxic penicillins with a partition coefficient below 1.0 and highly neurotoxic penicillins with a partition coefficient above 1.0.