Acute toxicity related to misuse (nonmedical use) of tramadol: Experience of the European Drug Emergencies Network Plus.

Following the development of the tramadol crisis currently affecting countries in the Middle East, and Africa, there has been increasing international interest in the regulation of tramadol. This study investigates the misuse of tramadol in patients presenting to emergency departments across Europe. Data from 32 emergency departments in 21 countries were extracted from the Euro-DEN Plus database for the 4-year period from 1 January 2014 to 31 December 2017. Of the reported 24,957 emergency department presentations, tramadol misuse was reported in 105 (0.4% presentations). Tramadol misuse was most common in Bratislava (Slovakia; n = 11, 7.5% of all presentations to this centre), Riga (Latvia; n = 4, 4.9%) and Munich (Germany; n = 17, 2.9%). On arrival, 14 (13.3%) of presentations were in coma/Glasgow coma score ≤ 8 and 9 of these had a respiratory rate <12 breaths/min. These presentations potentially pose a significant burden on emergency departments with a large proportion requiring admission to hospital for ongoing care.

Gadolinium deposition and the potential for toxicological sequelae - A literature review of issues surrounding gadolinium-based contrast agents.

Every year, approximately 30 million magnetic resonance imaging scans are enhanced with gadolinium-based contrast agents (GBCAs) worldwide. Although the development of nephrogenic systemic fibrosis in patients with renal impairment is well-documented, over recent years it has become apparent that exposure to GBCAs can potentially result in gadolinium deposition within human bone and brain tissue even in the presence of normal renal function. This review will address some of the controversies surrounding the safety of GBCA administration based on evidence from in vivo experiments, animal studies and clinical studies. We additionally evaluate the potential risk of toxicity from exposure to gadolinium in light of new guidance published by the US Food and Drug Administration and the European Medicines Agency, and discuss whether gadolinium deposition disease exists as a new diagnosis.

Gadolinium Concentrations in Biological Matrices From Patients Exposed to Gadolinium-Based Contrast Agents.

OBJECTIVES: There is increasing evidence that Gd may be retained within the skin, bones, and solid organs in patients with normal renal function after exposure to Gd-based contrast agents (GBCAs). Here we present clinical data from 19 patients who requested referral to our clinical toxicology service for assessment of potential "Gd toxicity." MATERIALS AND METHODS: Patients had undergone a median of 2 (interquartile range [IQR], 1-5) exposures to GBCAs and were reviewed at a median of 5 months (IQR, 2-8 months) after the last GBCA exposure. Patients had a clinical assessment by a clinical toxicologist, and biological samples were taken in 17 patients (89.5%). Gd concentrations were measured in these samples using inductively coupled plasma mass spectrometry. RESULTS: All patients had significant comorbidities, and after an extensive clinical review, none of the reported symptoms were considered likely to be related to "Gd toxicity." Whole blood, plasma, and urine samples had detectable Gd concentrations in 69.2%, 78.6%, and 95.2% of samples, respectively. Median (IQR) concentrations of Gd were as follows: whole blood, 0.013 ng/mL (IQR, limit of detection [LOD]-0.884 ng/mL); plasma, 0.012 ng/mL (IQR, LOD-0.046 ng/mL); and spot urine, 0.304 µg/g creatinine (IQR, 0.070-3.702 µg/g creatinine). There were positive correlations between whole blood and plasma (P = 0.0024, r = 0.84), whole blood and urine (P = 0.0018, r = 0.82), and plasma and urine (P = 0.0001, r = 0.89) Gd concentrations. There was a negative correlation between Gd concentrations and the period after exposure for whole blood (P = 0.0028, r = -0.80), plasma (P = 0.0004, r = -0.86), and urine (P < 0.0001, r = -0.91). CONCLUSIONS: We identified detectable Gd concentrations in biological matrices from all patients reporting exposure to GBCAs who were reviewed in our clinical toxicology outpatient clinic with concerns regarding potential "Gd toxicity"; however, there were no clinical features of toxicity present in this cohort. Further research is required to explore the pharmacokinetics and pharmacodynamics of GBCAs in patients with normal renal function and to determine the clinical significance of these detectable Gd concentrations.

Gadolinium-based contrast agents - what is the evidence for 'gadolinium deposition disease' and the use of chelation therapy?

Introduction: Gadolinium-based contrast agents are widely used for magnetic resonance imaging and, until recently, had been generally considered to have an excellent safety profile in patients with normal renal function. Nephrogenic systemic fibrosis is a well-established disease process involving fibrosis of the skin and internal organs seen in some patients with severely impaired renal function following exposure to these agents. Following reports that individuals with normal renal function may experience gadolinium deposition within brain and bone tissue, the term "gadolinium deposition disease" has been proposed and the use of chelating agents has been recommended to treat this "disease".Objectives: This review will address the clinical evidence for "gadolinium deposition disease" and discuss whether chelation therapy is appropriate for individuals who believe they have this condition.Methods: Electronic databases (PUBMED, Ovid MEDLINE and EMBASE) were searched up to 1st October 2019 for all studies evaluating clinical signs or symptoms related to potential gadolinium toxicity post-gadolinium-based contrast agent exposure in subjects with normal renal function, or papers evaluating the potential chelation of gadolinium in humans.Does "gadolinium deposition disease" exist as a novel condition? We identified four clinical studies relating to "gadolinium deposition disease", including one that included some discussion of the use of chelation therapy. Two of the clinical studies presented data from anonymous online surveys that recruited participants from support forums for people who self-identified as having gadolinium-based contrast agent-induced toxicity, with questions focussing on their reported symptoms and signs. The published literature to date has demonstrated that gadolinium deposition within the brain primarily occurs within the dentate nucleus and globus pallidus. These patients did not complain of movement disorders, but instead reported generalised sensory symptoms, which would not be expected to occur with pathology in these areas of the brain. There was considerable selection bias and a lack of available clinical information to exclude alternative medical diagnoses for these series, thus rendering the results difficult to interpret.Role of chelation therapy in patients exposed to gadolinium-based contrast agent: One study reported data from 25 patients who were diagnosed with "gadolinium deposition disease" according to unspecified criteria and were treated with intravenous calcium or zinc trisodium pentetate. The authors reported an increase in urine gadolinium concentrations following administration of the chelating agents, which they attributed to re-chelation of gadolinium from tissue deposits, however, there are insufficient data to be able to substantiate this.Conclusion: There is currently no published information from well-designed clinical studies that support a link between gadolinium deposition and the development of clinical sequelae in patients with normal renal function. Clinicians should exercise caution when considering whether or not gadolinium is of relevance in patients reporting symptoms after administration of gadolinium-based contrast agents. The inappropriate use of chelation therapy in patients with no clear evidence-based indication for their use potentially increases the risk of clinically significant harm to these patients from the adverse effects of chelation. Further research and well-designed clinical and epidemiological surveillance is needed to determine whether there are toxicological risks related to gadolinium exposure from the use of gadolinium-based contrast agents in patients with normal renal function.

Establishing Reference Intervals for Gadolinium Concentrations in Blood, Plasma, and Urine in Individuals Not Previously Exposed to Gadolinium-Based Contrast Agents.

OBJECTIVES: Over the recent years, there have been increasing concerns that exposure to gadolinium-based contrast agents (GBCAs) may be associated with retention of Gd within the skin, bones, and solid organs in patients with normal renal function, although the clinical implications of this deposition remain to be established. There are no published data available to guide the development of reference intervals for Gd concentrations in biological samples from healthy people. The aims of this study were to (1) determine whether healthy individuals who have not received GBCAs have detectable concentrations of Gd in their blood and urine, and (2) to develop a reference range for Gd concentrations in blood and spot urine samples for healthy individuals. MATERIALS AND METHODS: Whole blood, plasma, and spot urine samples were taken from 120 healthy volunteers with estimated glomerular filtration rate 70 mL/min per 1.73 m or greater. Gd concentrations were measured in these samples using inductively coupled plasma mass-spectrometry. The reference intervals for Gd concentrations in whole blood, plasma, and urine were estimated as the 2.5th percentile and the upper reference limit as the 97.5th percentile. RESULTS: Ten (8.33%) of the 120 subjects had detectable concentrations of Gd in their whole blood (n = 5) or spot urine (n = 5) samples; no subjects had detectable concentrations of Gd in their plasma samples. Our proposed reference intervals for Gd are as follows: whole blood, <0.008 ng/mL or <0.050 nmol/L; plasma, <0.009 ng/mL or <0.057 nmol/L; spot urine, <0.036 µg/g or <0.0250 nmol/mmol. CONCLUSIONS: The results of this study provide reference intervals for whole blood, plasma, and urine Gd concentrations in healthy subjects who have not previously received GBCAs and will assist clinicians in assessing patients who have concerns regarding potential Gd retention postexposure and help guide further clinical studies to explore the pharmacokinetics of GBCAs in patients with normal renal function.