Lacosamide intoxication in attempted suicide

Clinical characteristics of acute lacosamide poisoning: Pavia Poison Control Centre experience

AIMS

Lacosamide is a third-generation antiepileptic drug used as adjunctive therapy for partial seizures. Since its approval in 2008 very few cases of lacosamide overdose have been described in literature. The aim of our study was to evaluate clinical characteristics of acute lacosamide poisoning.

METHODS

A retrospective observational study was performed including all cases of acute lacosamide poisoning referred to Pavia Poison Control Centre from January 2012 to December 2021. For each patient age, sex, ingested dose, coingestants, clinical manifestations, treatment and outcome were collected.

RESULTS

A total of 31 subjects (median age 39 years, [interquartile range: 26.5-46.5]; females 22/31) were included. The median lacosamide ingested dose was 1500 mg [650-2800]. In 35.5% of cases lacosamide was the single ingested substance, while in 64.5% coingestants were also present. Coingestants varied from a minimum of 1 to a maximum of 3, with the more common being benzodiazepines and valproic acid. Clinical manifestations were present in 87% patients the most common were: vomiting (29%); seizures (29%), coma (25.8%), drowsiness (25.8%), confusion (12.9%), agitation (12.9%), tachycardia (12.9%), tremors (9.7%), bradycardia (9.7%), headache (6.5%) and hypertension (3.2%). The median lacosamide ingested dose was significantly higher in patients that experienced coma compared to patient who did not (2800 vs. 800 mg; P = .0082). Orotracheal intubation was necessary in 32.3% of patients. All patients fully recovered.

CONCLUSION

Lacosamide acute overdose may lead to a severe clinical picture. Dentral nervous system symptoms predominated, particularly seizures and coma occurred in a high percentage of cases.

Topiramate intoxications & hemodialysis - Literature review and the first case report of a massive suicidal intoxication treated with hemodialysis

Background

Topiramate is an anticonvulsant from sulfamate-substituted monosaccharides that is increasingly used to treat migraines. Serious topiramate intoxications have been described. Unfortunately, indications for and the effect of interventions, including hemodialysis, in severe intoxications seem expert-based and lack empirical evidence. We aim to review the literature on topiramate intoxication cases and to describe the first topiramate intoxication with toxicokinetic data following treatment with hemodialysis.

Methods

A literature review was conducted using the PubMed database. Included articles were reviewed for symptoms; management, including acute hemodialysis; toxicokinetic data; and outcomes.

Results

We found 61 hits in the PubMed database and checked 392 references in the snowball search; 22 were included for data extraction, reporting 29 cases. The majority of the patients were female (n = 23/29, 79%), ranging in age from 2 to 44 years (median 21). The ingested topiramate amount ranged from 175 to 40,000 mg (usual maintenance dose of 50 mg BID and a general maximum of 500 mg BID). Topiramate concentrations were reported in eight cases, ranging from 3.7 to 356.6 mg/L (for reference, the therapeutic range is 2-30 mg/L). Serious topiramate intoxications can result in seizures, coma, hemodynamic instability and severe metabolic acidosis. In no single case was hemodialysis used.

Conclusion

Serious symptoms of topiramate intoxications exist, and hemodialysis is used infrequently. If symptoms are refractory to symptomatic treatment, hemodialysis can reduce topiramate concentrations and symptomatology.

New Methods Used in Pharmacokinetics and Therapeutic Monitoring of the First and Newer Generations of Antiepileptic Drugs (AEDs)

The review presents data from the last few years on bioanalytical methods used in therapeutic drug monitoring (TDM) of the 1st-3rd generation and the newest antiepileptic drug (AEDs) cenobamate in patients with various forms of seizures. Chemical classification, structure, mechanism of action, pharmacokinetic data and therapeutic ranges for total and free fractions and interactions were collected. The primary data on bioanalytical methods for AEDs determination included biological matrices, sample preparation, dried blood spot (DBS) analysis, column resolution, detection method, validation parameters, and clinical utility. In conclusion, the most frequently described method used in AED analysis is the LC-based technique (HPLC, UHPLC, USLC) combined with highly sensitive mass detection or fluorescence detection. However, less sensitive UV is also used. Capillary electrophoresis and gas chromatography have been rarely applied. Besides the precipitation of proteins or LLE, an automatic SPE is often a sample preparation method. Derivatization was also indicated to improve sensitivity and automate the analysis. The usefulness of the methods for TDM was also highlighted.

Α Simple Method for the Determination of Lacosamide in Blood by GC-MS

Lacosamide is a functionalized amino acid with antiepileptic function. Therapeutic drug monitoring (TDM) in patients for lacosamide is critical as it allows clinicians to control epileptic seizures. A single liquid-liquid extraction step was applied for the extraction of lacosamide from whole blood samples which were thereafter analyzed by GC-MS. Optimum extraction conditions were selected on the basis of experiments with various solvents at different pHs, indicating ethyl acetate at pH 12 as the most efficient parameters for the extraction of lacosamide. Method exhibited linearity from 2 to 100 μg/mL with R²  = 0.998. Accuracy and precision were evaluated at three concentrations and found to be within acceptable limits. LOD and LOQ were determined at 0.1 and 0.5 μg/mL, respectively. Lacosamide was found to be stable at storage conditions. The developed method was applied successfully in clinical samples and postmortem blood sample from an overdose case.

Lacosamide: a Study of Exposures Reported to US Poison Centers over a 9-Year Period

BACKGROUND

Lacosamide (Vimpat®) is an anticonvulsant used to treat partial-onset seizures. Little is known about the characteristics and outcomes of patients exposed to lacosamide.

OBJECTIVE

To characterize lacosamide exposures reported to US poison centers with regard to patient demographics, clinical effects, and outcomes.

METHODS

This retrospective observational study queried the National Poison Data System (NPDS) for single substance lacosamide exposures from January 2008 to December 2016. Variables of interest included age, gender, medical outcome, management site, level of healthcare facility, reason for exposure, and clinical effects.

RESULTS

Lacosamide exposures were identified in 1124 patients, ranging from ages 2 months to 99 years. Six hundred and twenty-two patients (55.3%) were female. Nine hundred and seventy-six patients (86.8%) had minimal or no toxic effects. Life-threatening exposures numbered 30 cases (2.7%). There was one death. Five hundred and forty-eight patients (48.8%) did not require healthcare management while 537 (47.7%) were either referred to or already at a hospital. Among those treated at a healthcare facility, 269 (50.1%) did not require admission. Thirty-three patients (6.1%) were admitted to a psychiatric facility, 68 (12.7%) to a non-critical care unit, and 93 (17.3%) to a critical care unit. Six hundred and thirty-two exposures (56.2%) were due to therapeutic error. Suicide attempts numbered 168 (14.9%). Neurologic, gastrointestinal, and cardiovascular symptoms were commonly encountered.

CONCLUSION

Lacosamide exposures infrequently cause death or disability; however, a considerable proportion of the study population required intensive care. Exposed patients with symptoms require healthcare evaluation.

Lacosamide Overdose: A Case of QRS Prolongation and Seizure

BACKGROUND

Lacosamide is a third-generation antiepileptic drug. Its likely mechanism of action is via neuronal sodium channel blockade, via a unique manner compared with other antiepileptic drugs that block sodium channels. A paucity of information exists regarding lacosamide overdosage. Lacosamide overdosage is thought to cause QRS prolongation and seizures, due to its effect of sodium channel blockade. The potential efficacy of sodium bicarbonate to reverse the effects of lacosamide has not been well studied. Furthermore, prior reports of lacosamide toxicity have occurred in the setting of concomitant polypharmacy. Thus, the isolated toxic effects of the drug have not been well elucidated.

CASE REPORT

We report a case of a suspected, single-ingestion overdose on lacosamide. The patient developed signs of cardiotoxicity and seizure. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: After lacosamide overdosage, the emergency physician must be capable of acute management of subsequent lacosamide toxicity. Understanding the mechanisms of action causing toxicity due to this drug can help the clinician to anticipate the interventions that may be needed or useful to treat this potentially toxic ingestion.

The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs

Epilepsy is a neurologic disorder affecting approximately 50 million people worldwide, or about 0.7% of the population [1]. Thus, the use of anticonvulsant drugs in the treatment of epilepsy is common and widespread. There are three generations of anticonvulsant drugs, categorized by the year in which they were developed and released. The aim of this review is to discuss the pharmacokinetics, drug-drug interactions, and adverse events of the third generation of anticonvulsant drugs. Where available, overdose data will be included. The pharmacokinetic properties of third-generation anticonvulsant drugs include relatively fewer drug-drug interactions, as well as several unique and life-threatening adverse events. Overdose data are limited, so thorough review of adverse events and knowledge of drug mechanism will guide expectant management of future overdose cases. Reporting of these cases as they occur will be necessary to further clarify toxicity of these drugs.

The efficacy of lacosamide as monotherapy and adjunctive therapy in focal epilepsy and its use in status epilepticus: clinical trial evidence and experience

Lacosamide (LCM) is approved for anticonvulsive treatment in focal epilepsy and exhibits its function through the slow inactivation of voltage-gated sodium channels (VGSCs). LCM shows comparable efficacy with other antiepileptic drugs (AEDs) licensed in the last decade: in three randomized placebo-controlled trials, significant median seizure reduction rates of 35.2% for 200 mg/day, 36.4-39% for 400 mg/day and 37.8-40% for 600 mg/day were reported. Likewise, 50% responder rates were 38.3-41.1% for 400 mg/day and 38.1-41.2% for 600 mg/day. Similar rates were reported in post-marketing studies. The main adverse events (AEs) are dizziness, abnormal vision, diplopia and ataxia. Overall, LCM is well tolerated and has no clinically-relevant drug-drug interactions. Due to the drug's intravenous availability, its use in status epilepticus (SE) is increasing, and the available data are promising.

Cardiac sodium channel blockade after an intentional ingestion of lacosamide, cyclobenzaprine, and levetiracetam: Case report

CONTEXT

Lacosamide treats partial seizures by enhancing slow inactivation of voltage-gated sodium channels. The described cardiac toxicity of lacosamide in the literature to date includes atrioventricular blockade (PR prolongation), atrial flutter, atrial fibrillation, sinus pauses, ventricular tachycardia and a single cardiac arrest. We report a second case of cardiac arrest following an intentional lacosamide overdose.

CASE DETAILS

A 16 year-old female with a seizure disorder was found unresponsive in pulseless ventricular tachycardia after intentionally ingesting 4.5 g (76 mg/kg) lacosamide, 120 mg (2 mg/kg) cyclobenzaprine and an unknown amount of levetiracetam. Exact time of ingestion was unknown. Her initial electrocardiogram (ECG) demonstrated sinus tachycardia at 139 beats per minute, QRS duration 112 ms, and terminal R-wave in lead aVR > 3 mm. Despite treatment with 150 mEq of sodium bicarbonate, she had persistent EKG findings eight hours after presentation. Her serum lacosamide concentration nine hours after presentation was elevated at 22.8 μg/mL, while serum cyclobenzaprine concentration was 16 ng/mL (therapeutic: 10-30 ng/mL), and serum levetiracetam concentration was 22.7 μg/mL (therapeutic: 12-46 μg/mL). On hospital day three, ECG demonstrated resolution of the terminal R-wave with QRS of 78 ms. The patient recovered without physical or neurologic sequelae.

DISCUSSION

The patient's lacosamide, cyclobenzaprine and levetiracetam overdose was associated with QRS prolongation and terminal right axis deviation--suggesting sodium channel blockade as a likely etiology for her cardiac arrest. Cyclobenzaprine has potential for sodium channel blockade and ventricular dysrhythmias although cardiac toxicity due to cyclobenzaprine alone is rare. The combination of cyclobenzaprine with lacosamide may have resulted in cardiovascular collapse. In conclusion, overdose of lacosamide combined with therapeutic concentrations of sodium channel blocking xenobiotics may cause cardiac conduction delays and cardiac arrest.

Efficacy and tolerability of lacosamide in the concomitant treatment of 130 patients under 16 years of age with refractory epilepsy: a prospective, open-label, observational, multicenter study in Spain

Background

The safety and effectiveness of lacosamide, an antiepileptic drug (AED) that selectively enhances the slow inactivation of voltage-gated sodium channels without affecting rapid inactivation, has been demonstrated in randomized, double-blind, placebo-controlled trials in adults with focal epileptic seizures. Although lacosamide is approved for use in patients over 16 years of age, limited clinical experience exists for younger patients.

Objective

To assess the efficacy and tolerability of lacosamide in children with refractory epilepsy.

Design/Methods

The trial was a prospective, open-label, observational, multicenter study. A total of 130 patients aged less than 16 years (range 6 months to 16 years) with refractory epilepsy who had initiated treatment with lacosamide were enrolled at 18 neuropediatric units in hospitals across Spain. Patients with a variety of etiologies were enrolled, including those with partial epilepsies and symptomatic, generalized epilepsy syndromes. Lacosamide (VIMPAT®; UCB Pharma SA, Brussels, Belgium) was primarily administered once every 12 hours as an oral solution or as an oral tablet, with an initial dose of 1–2 mg/kg/day in the majority of cases. The majority of patients were also receiving stable concomitant therapy with ≥1 other AED. Treatment response to lacosamide was determined by assessing the change in seizure frequency after 3 months of lacosamide therapy. Responders were defined as patients who achieved a seizure frequency reduction of >50%. Tolerability was assessed by the reporting of adverse effects, laboratory testing, and electroencephalography recordings.

Results

Lacosamide was dosed at a mean of 6.80 ± 2.39 mg/kg/day. After 3 months of lacosamide therapy, 62.3% of patients achieved a >50% reduction in seizure frequency, with complete seizure suppression being reported in 13.8% of patients. Adverse effects occurred in 39 patients (30%), but no dose-response relationship was observed in terms of these events. In ten patients, instability, difficulty walking, an inability to relate to subjective elements, and blurred vision or dizziness were reported. A total of 13 patients discontinued treatment — in five of these patients, symptom intensity remained unchanged despite dose reduction, which led to treatment discontinuation. The symptoms were markedly different in each patient, preventing determination of a causal factor(s).

Conclusions

The results of this study provide preliminary evidence for the efficacy of lacosamide in children with refractory epilepsy. Further evaluation in a randomized, controlled trial is needed to validate the efficacy in this population and to fully investigate the adverse effects described here. We recommend an initial dose of 1–2 mg/kg/day, uptitrated to 6–9 mg/kg/day over 4–6 weeks.

Pharmacotherapy of the third-generation AEDs: lacosamide, retigabine and eslicarbazepine acetate

INTRODUCTION

The search for new, more effective antiepileptic drugs (AEDs) continues. The three most recently approved drugs, the so-called third-generation AEDs, include lacosamide, retigabine and eslicarbazepine acetate and are licensed as adjunctive treatment of partial epilepsy in adults.

AREAS COVERED

For the above three AEDs, their mechanisms of action, pharmacokinetic characteristics, drug-drug interactions, pharmacotherapeutics, dose and administration and therapeutic drug monitoring are reviewed in this paper.

EXPERT OPINION

Lacosamide and retigabine act through novel mechanisms, while eslicarbazepine acetate, a pro-drug for eslicarbazepine, acts in a similar manner to several other AEDs. All three AEDs are associated with linear pharmacokinetic and rapid absorption and undergo metabolism. Their drug-drug interaction profile is low (lacosamide and retigabine) to modest (eslicarbazepine) in propensity. At the highest approved doses for the three AEDs, responder rates were similar. The most commonly observed adverse effects compared with placebo were dizziness, headache, diplopia and nausea for lacosamide; dizziness, somnolence and fatigue for retigabine and dizziness and somnolence for eslicarbazepine acetate. The precise role that these new AEDs will have in the treatment of epilepsy and whether they will make a significant impact on the prognosis of intractable epilepsy is not yet known and will have to await further clinical experience.

Intravenous lacosamide in status epilepticus and seizure clusters

Status epilepticus (SE) and seizure clusters (SC) represent neurologic emergencies with a case fatality rate up to 34%, depending on cause and comorbidity. As SE becomes more refractory to treatment over time, appropriate medication is important. This study aimed to investigate efficacy and tolerability of intravenous (IV) lacosamide (LCM) in treatment of SC and SE. Data of patients with SE or SC who were treated with IV LCM between December 2009 and February 2011 in two Austrian centers were analyzed retrospectively. Clinical information was extracted from patients' charts. Forty-eight patients (26f/22m) aged median 62 years (range 17-95 years) were identified. Thirty-five percent of patients (17 of 48) had SC and 65% (31 of 48) had SE. SE was nonconvulsive in 10 (32%), convulsive in 11 (36%), and focal in 10 (32%) patients. SE was acute symptomatic in six (20%) and remote symptomatic in 11 (35%) patients. Fourteen (45%) had preexisting epilepsy. Median initial bolus dose was 200 mg (range 200-400 mg) in patients with SE and 200 mg in patients with SC. Maximum infusion rate was 60 mg/min. Cessation was observed in 42 patients (88%). Success rate in patients with SE receiving LCM as first or second drug was 100% (8 of 8), as third drug 81% (11 of 15), and as fourth or later drug 75% (6 of 8). There were no side effects observed except for pruritus and skin rash in two patients. These data support use of IV LCM as a potential alternative to standard antiepileptic drugs for acute treatment of seizure emergency situations, although randomized controlled studies are needed.

Experience with lacosamide in a series of children with drug-resistant focal epilepsy

We report our pediatric experience with lacosamide, a new antiepileptic drug, approved by the US Food and Drug Administration as adjunctive therapy in focal epilepsy in patients more than 17 years old. We retrospectively reviewed charts for lacosamide use and seizure frequency outcome in patients with focal epilepsy (Wilcoxon signed rank test). Sixteen patients (7 boys) were identified (median dose 275 mg daily, 4.7 mg/kg daily; mean age 14.9 years, range 8-21 years). Patients were receiving a median of 2 antiepileptic drugs (interquartile range [IQR] 1.7-3) in addition to having undergone previous epilepsy surgery (n=3), vagus nerve stimulation (n=9), and ketogenic diet (n=3). Causes included structural (encephalomalacia and diffuse encephalitis, 1 each; stroke in 2) and genetic abnormalities (Aarskog and Rett syndromes, 1 each) or cause not known (n=10). Median seizure frequency at baseline was 57 per month (IQR 7-75), and after a median follow-up of 4 months (range 1-13 months) of receiving lacosamide, it was 12.5 per month (IQR 3-75), (P<0.01). Six patients (37.5%; 3 seizure free) were classified as having disease that responded to therapy (≥50% reduction seizure frequency) and 10 as having disease that did not respond to therapy (<50% in 3; increase in 1; unchanged in 6). Adverse events (tics, behavioral disturbance, seizure worsening, and depression with suicidal ideation in 1 patient each) prompted lacosamide discontinuation in 4/16 (25%). This retrospective study of 16 children with drug-resistant focal epilepsy demonstrated good response to adjunctive lacosamide therapy (median seizure reduction of 39.6%; 37.5% with ≥50% seizure reduction) without severe adverse events.

Moderate toxic effects following acute zonisamide overdose

Zonisamide is an antiepileptic drug that acts on voltage-sensitive sodium and calcium channels, with a modulatory effect on GABA-mediated neuronal inhibition and an inhibitory effect on carbonic anhydrase. It is used mainly for the treatment of partial seizures, and is generally well tolerated at therapeutic doses. The most common reported adverse effects are somnolence, anorexia, dizziness, and headache. There are limited data on zonisamide overdose in the literature, and no case of zonisamide mono-intoxication has been published to date. We describe the first case of zonisamide mono-intoxication in a 25-year-old woman who ingested 12.6 g of this substance with suicidal intent. Despite a plasma zonisamide concentration of 182 mg/L on admission, the patient exhibited a benign clinical course with vomiting and central nervous system depression, requiring brief intubation. Somnolence persisted for 50 hours, and normal-anion-gap metabolic acidosis and polyuria for several days. Complete recovery may be expected with supportive care, even after ingestion of large zonisamide overdoses.

Lacosamide in the treatment of acute recurrent seizures and periodic epileptiform patterns in critically ill patients

We investigated the safety, tolerability, and effectiveness of lacosamide (LCM) in patients with acute recurrent seizures or with periodic epileptiform activity captured during continuous EEG monitoring. A total of 17 patients received LCM; 12 patients received LCM as a second or third antiepileptic drug (AED), one patient as a fourth AED, and one patient as a fifth AED. No additional AEDs were introduced after LCM in 15 patients. Twelve patients responded to LCM with improvement in the seizures or periodic epileptiform activity. Two patients required further AED management or burst suppression. No adverse effects, including symptomatic bradycardia and allergic reactions, were seen for intravenous infusion dosages up to 300 mg. Eleven patients were eventually discharged on LCM. LCM is an important new AED in the add-on treatment of acute recurrent seizures and periodic epileptiform activity in critically ill patients.