Population pharmacokinetics of intravenous paracetamol in critically ill patients with traumatic brain injury

Susceptibility to Hepatotoxic Drug-Induced Liver Injury Increased After Traumatic Brain Injury in Mice

The early stages of brain injury can induce acute liver injury, which can be recovered in the short term. Continued medication treatment during hospitalization for brain injury alleviates the prognosis and contributes to a high incidence of drug-induced liver injury (DILI). We hypothesize that there is an interaction between changes in the hepatic environment after brain injury and liver injury produced by intensive drug administration, leading to an upregulation of the organism's sensitivity to DILI. In this study, mice models of TBI were established by controlled cortical impact (CCI) and models of DILI were constructed by acetaminophen (APAP). All mice were divided into four groups: Sham, TBI, APAP, and TBI+APAP, and related liver injury indicators in liver and serum were detected by Western blot, Quantitative real-time PCR (qRT-PCR), and immunohistochemical staining. The results suggested that liver injury induced in the early stages of brain injury recovered in 3 days, but this state could still significantly aggravate DILI, represented by higher liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), oxidative stress (increase in malondialdehyde [MDA] concentration and deregulation of glutathione [GSH] and superoxide dismutase [SOD] activities), inflammatory response (activation of the HMGB1/TLR4/NF-κB signaling pathway, and increased messenger RNA [mRNA] and protein levels of pro-inflammatory cytokines including tumor necrosis factor alpha [TNF-α], interleukin [IL]-6, and IL-1β), and apoptosis (TUNEL assay, upregulation of Bax protein and deregulation of Bcl-2 protein). In summary, our results suggested that TBI is a potential susceptibility factor for DILI and exacerbates DILI.

Population Pharmacokinetic Modeling and Dose Optimization of Acetaminophen and its Metabolites Following Intravenous Infusion in Critically ill Adults

BACKGROUND AND OBJECTIVE

Acetaminophen (paracetamol) is a ubiquitously administered drug in critically ill patients. Considering the dearth of literature, we evaluated the population pharmacokinetics of intravenous acetaminophen and its principal metabolites (sulfate and glucuronide) in this population.

METHODS

Critically ill adults receiving intravenous acetaminophen were included in the study. One to three blood samples were withdrawn per patient for the estimation of acetaminophen, and its metabolites (acetaminophen glucuronide and acetaminophen sulfate). High-performance liquid chromatography was used for measuring serum concentrations. We used nonlinear mixed-effect modeling for estimating the primary pharmacokinetic parameters of acetaminophen and its metabolites. The effect of covariates was evaluated followed by dose optimization using Monte Carlo simulation. Patient factors such as demographic information, liver and renal function tests were used as covariates in population pharmacokinetic analysis. The therapeutic range for serum acetaminophen concentration was considered to be 66-132 μM, while 990 μM was considered as the threshold for toxic concentration.

RESULTS

Eighty-seven participants were recruited. A joint two-compartment acetaminophen pharmacokinetic model linked to glucuronide and sulfate metabolite compartments was used. The central and peripheral volume distributions were 7.87 and 8.87 L/70 kg, respectively. Estimated clearance (CL) was 0.58 L/h/70 kg, while intercompartmental clearance was 44.2 L/h/70 kg. The glucuronide and sulfate metabolite CL were 22 and 94.7 L/h/70 kg, respectively. Monte Carlo simulation showed that twice-daily administration of acetaminophen would result in a relatively higher proportion of patient population achieving and retaining serum concentrations in the therapeutic range, with reduced risk of concentrations remaining in the toxic range.

CONCLUSION

A joint pharmacokinetic model for intravenous acetaminophen and its principal metabolites in a critically ill patient population has been developed. Acetaminophen CL in this patient population is reduced. We propose a reduction in the frequency of administration to reduce the risk of supra-therapeutic concentrations in this population.

Poly(butyl cyanoacrylate) nanoparticles-deliveredβ-nerve growth factor promotes the neurite outgrowth and reduces the mortality in the rat after traumatic brain injury

Several transport vectors, including nanoparticles, have been reported to be used for the delivery of therapeutic medicines crossing the impermeable blood-brain barrier (BBB) to treat the diseases in the central nerve system (CNS), such as traumatic brain injury (TBI). Poly(n-butyl-2-cyanoacrylate) (PBCA) nanoparticles, made from biocompatible material, are regarded as a better potential delivery tool than others such as gold nanoparticles due to their degradabilityin vivo. However, little is known whether PBCA nanoparticles can be used to deliver neurotrophic factors into the brain to treat TBI. In this study, we first synthesized PBCA-carriedβ-nerve growth factor, a neurotrophic agent with a large molecular weight, and then intravenously injected the compound into TBI rats. We found that despite undergoing several synthesis steps and host circulation,β-NGF was able to be successfully delivered into the injured brain by PBCA nanoparticles, still maintain its neurotrophic activity for neurite outgrowth, and reduce the mortality of TBI rats. Our findings indicate that PBCA nanoparticles, with Tween 80, are an efficient delivery vector and a protective reservoir for large molecular therapeutic agents to treat TBI intravenously.

Risk Factors for Intravenous Propacetamol-Induced Blood Pressure Drop in the Neurointensive Care Unit: A Retrospective Observational Study

BACKGROUND

Intravenous propacetamol is commonly used to control fever and pain in neurocritically ill patients in whom oral administration is often difficult. However, several studies reported that intravenous propacetamol may cause blood pressure drop. Thus, we aimed to investigate the occurrence and risk factors for intravenous propacetamol-induced blood pressure drop in neurocritically ill patients.

METHODS

This retrospective study included consecutive patients who were administered intravenous propacetamol in a neurointensive care unit at a single tertiary academic hospital between April 2013 and June 2020. The exact timing of intravenous propacetamol administration was collected from a database of the electronic barcode medication administration system. Blood pressure drop was defined as a systolic blood pressure below 90 mm Hg or a decrease by 30 mm Hg or more. Blood pressure, pulse rate, and body temperature were collected at baseline and within 2 h after intravenous propacetamol administration. The incidence of blood pressure drop was evaluated, and multivariable logistic regression analysis was performed to identify risk factors for blood pressure drop events.

RESULTS

A total of 16,586 instances of intravenous propacetamol administration in 4916 patients were eligible for this study. Intravenous propacetamol resulted in a significant decrease in systolic blood pressure (baseline 131.1 ± 17.8 mm Hg; within 1 h 124.6 ± 17.3 mm Hg; between 1 and 2 h 123.4 ± 17.4 mm Hg; P < 0.01). The incidence of blood pressure drop events was 13.5% within 2 h after intravenous propacetamol. Older age, lower or higher baseline systolic blood pressure, fever, higher Acute Physiology and Chronic Health Evaluation II score, and concomitant administration of vasopressors/inotropes or analgesics/sedatives were significant factors associated with the occurrence of blood pressure drop events after intravenous propacetamol administration.

CONCLUSIONS

Intravenous propacetamol can induce hemodynamic changes and blood pressure drop events in neurocritically ill patients. This study identified the risk factors for blood pressure drop events. On the basis of our results, judicious use of intravenous propacetamol is warranted for neurocritically ill patients with risk factors that make them more susceptible to hemodynamic changes.

Traumatic Brain Injury: A Forensic Approach: A Literature Review

Traumatic brain injury (TBI) is the principal cause of invalidity and death in the population under 45 years of age worldwide. This mini-review aims to systematize the forensic approach in neuropathological studies, highlighting the proper elements to be noted during external, radiological, autoptical, and histological examinations with particular attention paid to immunohistochemistry and molecular biology. In the light of the results of this mini-review, an accurate forensic approach can be considered mandatory in the examination of suspected TBI with medico-legal importance, in order to gather all the possible evidence to corroborate the diagnosis of a lesion that may have caused, or contributed to, death. From this point of view, only the use of an evidence-based protocol can reach a suitable diagnosis, especially in those cases in which there are other neuropathological conditions (ischemia, neurodegeneration, neuro-inflammation, dementia) that may have played a role in death. This is even more relevant when corpses, in an advanced state of decomposition, are studied, where the radiological, macroscopic and histological analyses fail to give meaningful answers. In these cases, immune-histochemical and molecular biology diagnostics are of fundamental importance and a forensic neuropathologist has to know them. Particularly, MiRNAs are promising biomarkers for TBI both for brain damage identification and for medico-legal aspects, even if further investigations are required to validate the first experimental studies. In the same way, the genetic substrate should be examined during any forensic examination, considering its importance in the outcome of TBI.