Population pharmacokinetic-pharmacodynamic model of subcutaneous bupivacaine in a novel extended-release microparticle formulation.

The objective of this study was to develop a population pharmacokinetic-pharmacodynamic model of subcutaneously administered bupivacaine in a novel extended-release microparticle formulation for postoperative pain management. Bupivacaine was administered subcutaneously in the lower leg to 28 healthy male subjects in doses from 150 to 600 mg in a phase 1 randomized, placebo-controlled, double-blind, dose-ascending study with two different microparticle formulations, LIQ865A and LIQ865B. Warmth detection threshold was used as a surrogate pharmacodynamic endpoint. Population pharmacokinetic-pharmacodynamic models were fitted to plasma concentration-effect-time data using non-linear mixed-effects modelling. The pharmacokinetics were best described by a two-compartment model with biphasic absorption as two parallel absorption processes: a fast, zero-order process and a slower, first-order process with two transit compartments. The slow absorption process was found to be dose-dependent and rate-limiting for elimination at higher doses. Apparent bupivacaine clearance and the transit rate constant describing the slow absorption process both appeared to decrease with increasing doses following a power function with a shared covariate effect. The pharmacokinetic-pharmacodynamic relationship between plasma concentrations and effect was best described by a linear function. This model gives new insight into the pharmacokinetics and pharmacodynamics of microparticle formulations of bupivacaine and the biphasic absorption seen for several local anaesthetics.

Dose safety and pharmacodynamics of subcutaneous bupivacaine in a novel extended-release microparticle formulation: A phase 1, dose-ascending study in male volunteers.

A novel microparticle-based extended-release local anaesthetic containing a bupivacaine/poly-lactic-co-glycolic acid (PLGA; LIQ865A) or plain bupivacaine (LIQ865B) was examined in a first-in-human trial. The objectives were to examine the dose safety/tolerability and pharmacodynamics. Randomized subcutaneous injections of LIQ865A (n = 16) or LIQ865B (n = 12) and diluent, contralaterally, were administered in a dose-ascending manner (150- to 600-mg bupivacaine). Subjects were admitted 24 h post-injection and followed for 30 days post-injection. The risk ratios (RRs; 95% CI) of erythematous reactions for LIQ865A versus diluent was 9.00 (1.81-52.23; P = 0.006) and for LIQ865B versus diluent 2.50 (0.69-9.94; P = 0.37). The RR for the development of hematomas (LIQ865A versus diluent) were 3.25 (1.52-8.16; P = 0.004) and 4.00 (0.72-24.89; P = 0.32) (LIQ865B versus diluent). Subcutaneous indurations persisting for 4-13 weeks were seen in 6/16 subjects receiving LIQ865A. One subject receiving LIQ865A (600-mg bupivacaine) developed intermittent central nervous system (CNS) symptoms of local anaesthetic systemic toxicity (85 min to 51 h post-injection) coinciding with plasma peak bupivacaine concentrations (490-533 ng/ml). Both LIQ865 formulations demonstrated dose-dependent hypoesthesia and hypoalgesia. The duration of analgesia ranged between 37 and 86 h. The overall number of local adverse events, however, prohibits clinical application without further pharmacological modifications.

Paliperidone poisoning and measurable plasma concentrations 2.5 years after last administered dose: A case report.

We report a poisoning with paliperidone palmitate, a once-monthly, long-acting injectable antipsychotic. The patient suffered from deep sedation and dystonia. She had been treated with extended release intramuscular paliperidone for several years and had received her last injection 8 days prior to admission. The plasma paliperidone was nearly five times higher than the upper reference range. Paliperidone is a substrate of p-glycoprotein and we therefore aimed to increase its elimination by inducing p-glycoprotein through treatment with St John's wort. This seemed to have a limited effect on paliperidone clearance. Plasma concentration levels decreased with time as did the dystonia. All antipsychotic treatment was discontinued after this unfortunate event, and the patient did specifically not receive any prescriptions of paliperidone or risperidone. However, the plasma paliperidone concentration was in the low end of the normal therapeutic range 2.5 years after the last dose of paliperidone was administered, and the patient still had some extrapyramidal symptoms.

Case report: A comatose patient with pregabalin overdose successfully treated with continuous renal replacement therapy.

Pregabalin (PB) overdose causes mild symptoms and coma is rarely seen unless the patient has also ingested sedatives and/or has preexisting renal disease. We present a case report of a suicide attempt with PB where the patient presented in a comatose state that was successfully treated with continuous renal replacement therapy (CRRT). Treatment of PB overdose is usually supportive. However, previous reports of PB overdose have been treated with intermittent hemodialysis (IHD) in patients with preexisting renal disease. The problem with IHD is that it is only available in specialist centers and unsuitable for unstable patients. In the following case report, the patient presented to the emergency department (ED) unconscious and hypotensive. It was thought that the patient tried to commit suicide by taking an overdose of zopiclone tablets, as empty packets of zopiclone tablets were found beside the patient. There was no effect with flumazenil treatment, so the patient was intubated, mechanically ventilated, and admitted to the intensive care unit (ICU) where inotropic support was started. Despite supportive therapy, there was no improvement in the patient's condition. Further investigation into the patient's medical records uncovered prescriptions of PB. Based on this finding, plasma PB levels were measured and found to be 20 times the upper limit of the therapeutic reference range. CRRT was instituted and after 6 h of treatment the patient woke up. Hospitals with ICUs often have CRRT available in their units whereas IHD is less readily available. This case report demonstrates that CRRT is an effective method for treating PB overdose in an unconscious unstable patient that was unsuitable for transfer to another hospital.

[Iatrogenic botulism in therapeutic use of botulinum toxin].

The review summarises the current knowledge of the treatment of iatrogenic botulinum toxin overdose. The symptoms may be diffuse, and suspicion should be raised based on time of symptom appearance relative to the time of exposure. Iatrogenic botulism may appear if the maximum recommended total dose of botulinum toxin has been exceeded and if the drug is spread locally from the site of injection or is redistributed to the systemic circulation. The adverse drug reactions frequency is possibly underreported. Fast initiation of the available antidote may be needed. The guideline provided on treatment of iatrogenic botulism is developed from non-iatrogenic botulism.

Has the time come to stop routine N-acetylcysteine treatment in young children in Denmark? A review of 300 suspected paracetamol overdoses in children aged 0-6 years.

AIM: To evaluate the prevalence of potentially hepatoxic paracetamol ingestion and associated N-acetylcysteine treatment in young children suspected of paracetamol poisoning. METHODS: A retrospective cohort study of children aged 0-6 years suspected of paracetamol poisoning with a related plasma-paracetamol measurement in the Capital Region of Denmark in the period 2010-2017. Data from the clinical laboratory system were linked to data from electronic patient records via the unique identification number given to all Danish residents. RESULTS: Of 297 children included, suspected single paracetamol overdoses were present in 281 (95%). Sixty-nine per cent were treated with N-acetylcysteine, and the mean treatment period was 20.3 h (SD 20.8). A maximum of 6 (2%) of the children suspected of single overdose had plasma-paracetamol concentrations that exceeded the recommended treatment thresholds. No cases of severe hepatotoxicity were registered. Adverse events to N-acetylcysteine-treatment were registered in 3 (2%) children including one anaphylactoid reaction (0.5%). CONCLUSION: This study shows that initiating N-acetylcysteine as a 'one size fit all' treatment regimen in all children aged 0-6 years with a suspected single paracetamol overdose leads to substantial overtreatment. The data support that it is feasible to initiate N-acetylcysteine within 10 h based on an early plasma-paracetamol test.

Phrenic nerve block on severe post-hepatectomy shoulder pain: A randomized, double-blind, placebo-controlled, pilot study.

BACKGROUND: Severe shoulder pain occurs frequently after surgery close to the diaphragm, potentially caused by referred pain via the ipsilateral phrenic nerve. We aimed to assess the analgesic effect of an ultrasound-guided phrenic nerve block on moderate to severe right-sided shoulder pain after open partial hepatectomy. METHODS: This was a randomized, double-blind, placebo-controlled, pilot study, comparing ultrasound-guided phrenic nerve block (ropivacaine 0.75 mg/mL) versus placebo (isotonic sodium chloride 0.9 mg/mL) on severe post-hepatectomy shoulder pain (NRS ≥6). Pre- and postoperative spirometry and arterial blood gas analyses were used to assess respiratory function. Subjects with chronic lung disease were excluded. Unfortunately, due to lack of funding, the trial was ended prematurely and therefore presented as a pilot study. RESULTS: One hundred and one subjects were screened for eligibility; 14 subjects were randomized, and two subjects were later excluded; thus, 12 subjects were analyzed with six in each group. A statistically significant difference in reduction in median pain intensity between groups was observed 15 minutes after phrenic nerve block ("ropivacaine first" ΔNRS: -6.0 [-6.0 to -3.0] vs. "saline first" ΔNRS: 0 [-6.0 to 1.0], P = .026). Spirometry results and arterial blood gas analyses were not clinically impacted by the block. CONCLUSIONS: Postoperative phrenic nerve block significantly reduced severe post-hepatectomy shoulder pain. Larger studies are warranted to confirm the lack of clinically relevant block-related impairment of respiratory function.

Medication errors in residential facilities based on Danish Poison Information Center inquiries.

INTRODUCTION: This study describes the types and health consequences of medication errors in residential facilities for which the Danish Poison Information Center (DPIC) was contacted. METHODS: This study is based on all inquiries made by residential facilities to the DPIC during a 13-month period. Information about inquirers and residents, data related to the medication error, symptoms, risk assessments and recommendations was collected, and a follow-up phone call was made to evaluate the clinical outcomes, preferably within one week. RESULTS: During the study period, the DPIC received 146 inquiries concerning medication errors in residential facilities. Nearly all inquiries concerned excess administration of medication (96%) and often involved medications targeting the nervous system (65%). In 9% of cases, the DPIC recommended hospitalisation. Most medication errors (92%) were considered of "no or minor risk". Administration of medication to the wrong resident is a frequent reason for consulting the DPIC (45%) in cases with medication errors. CONCLUSIONS: In this study, we inventoried the inquiries made to the DPIC about medication errors in residential facilities in Denmark. Most medication errors did not carry a risk of serious health consequences, but continued monitoring is warranted to minimise risk in this vulnerable population. FUNDING: Copenhagen Center for Health Technology (5001105002), Department of Clinical Pharmacology (Bispebjerg Hospital, The Capital Region) (1152871001). TRIAL REGISTRATION: not relevant.

A poison information centre can provide important assessment and guidance regarding medication errors in nursing homes: A prospective cohort study.

The Danish Poison Information Centre (DPIC) regularly receives inquiries about nursing home residents who have been exposed to a medication error. The aim of this prospective cohort study was to describe and discuss the types and consequences of these errors. Data were collected from 1 March 2018 to 31 March 2019. Registered data included characteristics of caller and resident, data related to the suspected medication error, risk assessment and recommendation. Consequences and clinical outcomes were assessed by follow-up telephone calls. Over the study period, the DPIC was consulted about 145 medication errors occurring at Danish nursing homes. The median number of substances administered by error was two (interquartile range 1-5). Hospitalization was recommended in 21% of cases. In one-third of the cases where consultation with the DPIC was done with the resident either on his/her way to or in hospital, hospitalization was found unnecessary, and the resident could have stayed in accustomed surroundings for observation. Follow-up demonstrated that very few medication errors had a severe outcome. This prospective study illustrates that consulting with a poison information centre can qualify risk assessment and potentially reduce hospital admissions following medication errors in a nursing home setting.

[Local anaesthetic systemic toxicity].

Local anaesthetic systemic toxicity (LAST) gives rise to symptoms from the central nervous and cardiovascular systems. Knowledge about symptoms and risk factors is crucial in preventing LAST. Treatment of severe symptoms should often include vasopressors and sodium bicarbonate. In cardiac arrest the guidelines for advance life support including high-quality cardiopulmonary resuscitation (CPR) should be followed - emphasising prolonged CPR and extracorporeal life support (ECLS) in case of LAST. The conclusion of this review is that intravenous lipid emulsion should only be considered, when other interventions fail, and ECLS is unavailable.

High-Dose Glucagon Has Hemodynamic Effects Regardless of Cardiac Beta-Adrenoceptor Blockade: A Randomized Clinical Trial.

Background Intravenous high-dose glucagon is a recommended antidote against beta-blocker poisonings, but clinical effects are unclear. We therefore investigated hemodynamic effects and safety of high-dose glucagon with and without concomitant beta-blockade. Methods and Results In a randomized crossover study, 10 healthy men received combinations of esmolol (1.25 mg/kg bolus+0.75 mg/kg/min infusion), glucagon (50 µg/kg), and identical volumes of saline placebo on 5 separate days in random order (saline+saline; esmolol+saline; esmolol+glucagon bolus; saline+glucagon infusion; saline+glucagon bolus). On individual days, esmolol/saline was infused from -15 to 30 minutes. Glucagon/saline was administered from 0 minutes as a 2-minute intravenous bolus or as a 30-minute infusion (same total glucagon dose). End points were hemodynamic and adverse effects of glucagon compared with saline. Compared with saline, glucagon bolus increased mean heart rate by 13.0 beats per minute (95% CI, 8.0-18.0; P<0.001), systolic blood pressure by 15.6 mm Hg (95% CI, 8.0-23.2; P=0.002), diastolic blood pressure by 9.4 mm Hg (95% CI, 6.3-12.6; P<0.001), and cardiac output by 18.0 % (95% CI, 9.7-26.9; P=0.003) at the 5-minute time point on days without beta-blockade. Similar effects of glucagon bolus occurred on days with beta-blockade and between 15 and 30 minutes during infusion. Hemodynamic effects of glucagon thus reflected pharmacologic glucagon plasma concentrations. Glucagon-induced nausea occurred in 80% of participants despite ondansetron pretreatment. Conclusions High-dose glucagon boluses had significant hemodynamic effects regardless of beta-blockade. A glucagon infusion had comparable and apparently longer-lasting effects compared with bolus, indicating that infusion may be preferable to bolus injections. Registration Information URL: https://www.clinicaltrials.gov; Unique identifier: NCT03533179.

Two-bag intravenous N-acetylcysteine, antihistamine pretreatment and high plasma paracetamol levels are associated with a lower incidence of anaphylactoid reactions to N-acetylcysteine.

Context:N-acetylcysteine (NAC) is used worldwide to prevent liver injury after paracetamol overdoses. Anaphylactoid reactions to NAC occur frequently and often lead to treatment interruptions or discontinuations. In Denmark in 2013, the NAC treatment regimen was simplified from a three-bag to a two-bag NAC regimen. Factors of importance for the development of anaphylactoid reaction to this new regimen are poorly explored. Previous studies have suggested a protective effect of high plasma levels of paracetamol on the development of anaphylactoid reactions. Likewise, exposure to antihistamines prior to NAC treatment may protect against these reactions.Methods: This is a retrospective cohort study of patients treated with NAC and with at least one plasma paracetamol sample performed in the Capital Region of Denmark from 2010 to 2017. The primary outcome was the incidence of anaphylactoid reactions to NAC requiring intravenous treatment with antihistamines and/or glucocorticoids. Logistic regression analyses were carried out to identify the risk of developing an anaphylactoid reaction to NAC affected by influencing factors.Results: Of 4315 admissions included in the study, 259 (6.0%) developed an anaphylactoid reaction to NAC. The two-bag regimen (adjusted OR 0.44 [95%CI: 0.32-0.60]), increasing age (adjusted OR 0.84 [95%CI: 0.78-0.90] per 10-year increase) or children <10 years (adjusted OR 0.14 [95%CI: 0.04-0.36]) and antihistamine co-ingestion in overdose (adjusted OR 0.17 [95%CI: 0.02-0.64]) were associated with significantly fewer anaphylactoid reactions. High plasma paracetamol concentrations protected against development of anaphylactoid reactions during the two-bag regimen (adjusted OR 0.59 [95%CI: 0.47-0.71] and three-bag regimen 0.82 [95%CI: 0.72-0.94] per doubling of paracetamol concentration). The effect differed between the two regimens (p = .004 for interaction).Conclusion: In this retrospective cohort, a high peak plasma paracetamol concentration, age, antihistamine co-ingestion and use of the two-bag NAC regimen were associated with fewer anaphylactoid reactions to NAC.

[Acute neuropathy and liver injury following the abuse of nitrous oxide].

This is a case report about two young men with extensive recreational use of nitrous oxide (N2O) in bulbs. Vitamin B12 deficiency was found in the first patient as well as signs of myelopathy on magnetic resonance imaging, and the second patient had acute liver injury. Physical examinations showed severe pathology with loss of motor function and affected sensory function in both patients. Recreational use of N2O is increasing in Denmark, but the extent of N2O abuse is not known. Attention to these effects of N2O abuse may be important when treating patients with acute N2O-intoxication.

Hemodynamic Effects of Intravenous, High-Dose Lipid Emulsion With and Without Metoprolol Infusion in Healthy Volunteers: A Randomized Clinical Trial.

In a double-blinded, randomized, crossover trial, we investigated the hemodynamic effects of high-dose intravenous lipid emulsion (ILE) with/without metoprolol. Ten healthy volunteers each completed 4 trial days (placebo + ILE; metoprolol + placebo; metoprolol + ILE; placebo + placebo) in random order. Metoprolol was administered as an initial bolus (10 mg), followed by an infusion (50 mg) from 5 to 30 minutes. ILE was administered as a bolus at 12.5 minutes (2.5 mL/kg), followed by a 15-minute infusion (0.25 mL/kg per minute). On metoprolol + ILE days (compared with metoprolol + placebo) after 120 minutes, mean heart rates were significantly higher (difference, 5.5 beats per minute (bpm); 95% confidence interval (CI), 3.0-8.1 bpm; P < 0.001), and average relative cardiac output was higher (difference, 10 percentage points; 95% CI, 5-15 percentage points; P < 0.001). The hemodynamic effect of ILE developed gradually. ILE had no effect on plasma metoprolol or major adverse events. In conclusion, high-dose ILE has relatively marginal and delayed hemodynamic effects that may have limited clinical relevance in the short-term clinical toxicological setting.

[Indications for orogastric emptying in poisonings are rarely present].

Orogastric aspiration (OA) without orogastric lavage has been the traditional gastric emptying method of choice in Denmark; this being based on national historic studies on poisoned patients. The treatment is still observed to be initiated prior to consultations with the Danish poisons information centre. In this review, we present relevant knowledge in the field of OA. The procedure should only be considered in very limited cases and never routinely. Also, an algorithm is presented for its rare use in relation to other more effective gastrointestinal decontamination methods.

[Limited evidence for effect and safety of propranolol for exam-related anxiety].

Propranolol is often prescribed to younger people with exam-related performance anxiety. Evidence for effect as well as safety is, however, sparse for this non-approved indication. Furthermore, only relatively large pack sizes are available in Denmark. This may spur an unnecessary, permanent overuse and increase the risk of overdosing and poisoning. The aim of this review is to examine the evidence for the effect as well as safety of propranolol for exam-related performance anxiety and to discuss, whether the use of this drug for this unapproved indication is rational.

Outcomes following calcium channel blocker exposures reported to a poison information center.

BACKGROUND: Calcium channel blockers (CCBs) are widely used drugs that have a narrow therapeutic index. Even minor overdoses must be treated in-hospital due to the risk of severe hypotension and bradycardia. We aimed to describe trends in CCB use and overdoses in Denmark. METHODS: Data on enquiries concerning CCBs reported to the Danish Poisons Information Center (DPIC) from January 2009 to January 2015 was coupled with data on hospitalization and mortality obtained from Danish National Registers. We obtained data on the general use of CCBs in Denmark and retrieved medical charts on fatal cases. RESULTS: From a total of 126,987 enquiries to the DPIC in 2009-2014 we identified 339 CCB unique exposures (3‰ of all). Children < 5 years accounted for 20% all exposures and these were classified as 'intake during playing' (61%) and 'medication errors' (39%). Among adults 'suicidal poisonings' (58%), and 'medication errors' (34%) were most frequent. A majority (81%) of exposures led to hospital admission. Seven patients (2%) died from the CCB exposure and all were adults with 'suicidal poisoning'. Amlodipine accounted for 95% of all CCB prescriptions, was involved in 71% of enquiries and in 29% of fatalities. Verapamil accounted for 3% of prescriptions, was involved in 13% of enquiries and 57% of fatalities. CONCLUSION: Four fifths of enquiries to the DPIC result in hospitalization and one fifth concern small children. Mortality were infrequent and occurred only in adults with suicidal exposures and with and an overrepresentation of verapamil exposures.

Effects of high-dose, intravenous lipid emulsion on laboratory tests in humans: a randomized, placebo-controlled, double-blind, clinical crossover trial.

Background Intravenous lipid emulsion (ILE) is used to treat drug poisonings. The resultant hyperlipemia may affect laboratory tests but the consequences are poorly characterized. In a clinical trial we therefore investigated the effects of ILE on laboratory tests analyzed on common analytical platforms (Roche® cobas 8000 and SYSMEX® flow-cytometry). Methods Ten healthy participants each completed 4 trial days (two with ILE and two with placebo). ILE (5.25 mL/kg) was administered from 12.5 to 30 min from baseline. At 0, 30 and 60 min, blood samples were drawn for measurement of 20 analytes. We investigated the effects of ILE on analyte levels and frequencies of exceedance of predefined analyzer hemolysis (H) or lipemia (L)-index cut-offs and test-specific reference change values (RCVs) on ILE-days. If the results were blocked due to exceedance of index values, we manually extracted the results. Results Sixteen out of 20 tests were blocked because H- or L-index cut-offs were exceeded on ILE-days. Differences in analyte levels between ILE- and placebo-days above the RCV were observed for aspartate aminotransferase, total calcium, lactate dehydrogenase (LDH), sodium and neutrophils. Mean values outside the normal range after ILE were observed for LDH (219 U/L), sodium (135.3 mmol/L) and total calcium (2.1 mmol/L). Conclusions ILE-infusion caused report failure of nearly all laboratory tests performed on a cobas 8000-platform, but it was possible to manually retrieve the results. For most test results - particularly alkaline phosphatase, bilirubin, phosphate and carbamide - the consequences of ILE were marginal, and the effects of ILE were reduced at the 60-min timepoint.