The safety of lacosamide for treatment of seizures and seizure prophylaxis in adult hospitalized patients

A prospective, real-world, clinical pharmacokinetic study to inform lacosamide dosing in critically ill patients undergoing continuous venovenous haemofiltration (PADRE-02)

AIMS

Although the use of continuous renal replacement therapy (CRRT) has increased, limited dosing information exists on the effect of CRRT on antiepileptic drug pharmacokinetics. The objectives of this practice-based study are to evaluate the pharmacokinetics of lacosamide and recommend individualized dosing recommendations in critically ill patients receiving continuous venovenous haemofiltration (CVVH).

METHODS

Seven patients receiving lacosamide and CVVH in a neurocritical care unit were enrolled. Pre-filter, post-filter and ultrafiltrate samples were obtained at baseline, right after the completion of the infusion, and up to six additional sampling time points post-administration. Patient-specific flow rates and clinical measures were also collected simultaneously at the time of sampling. Plasma concentrations were measured using a validated high-performance liquid chromatography with ultraviolet radiation detection (HPLC-UV) bioanalytical method. Non-compartmental analysis was utilized to characterize the pharmacokinetics of lacosamide.

RESULTS

The observed mean sieving coefficient for lacosamide was 0.80 ± 0.10, suggesting high removal of lacosamide. Concentrations measured in six out of seven patients were observed to be outside the therapeutic range (5-12 mg/L). The estimated average volume of distribution was found to be similar to healthy patients (0.58 L/kg). The mean bias and precision of the estimated total clearance was -2.53% and 14.9%, respectively. Simulations of various doses suggest that effluent flow rate-based dosing regimens could be used to individualize lacosamide therapeutics.

CONCLUSIONS

CVVH clearance contributed a major fraction of the total lacosamide clearance in neurocritically ill patients. Given that drug clearance increases with higher effluent flow rates, lacosamide dosing regimens should be increased to match exposures observed in patients with normal renal function.

Is Therapeutic Drug Monitoring of Lacosamide Needed in Patients with Seizures and Epilepsy?

Lacosamide is an antiepileptic drug (AED) that has linear pharmacokinetics, predictable blood concentrations, and few drug interactions, setting it apart from other AEDs that require vigorous therapeutic drug monitoring (TDM) such as phenytoin and carbamazepine. However, there have been reports of altered lacosamide pharmacokinetics in some populations. The purpose of this review is to determine whether lacosamide pharmacokinetics are altered in certain patient populations, suggesting the need for TDM. A literature search of Medline, Scopus, Embase, and Cochrane trials was conducted on January 3, 2019 (and then updated on September 2, 2019) to search for articles relevant to the TDM or pharmacokinetics of lacosamide. A total of 56 relevant articles were found and included in this review. Dose of lacosamide is linearly correlated with plasma concentrations and efficacy. However, currently there is no well-established reference range. Overall, the recommended reference ranges varied from 2.2 to 20 mg/L. Lacosamide has very few clinically relevant drug-drug interactions; however, there seems to be a significant drug interaction between lacosamide and enzyme-inducer AEDs. Based on available literature, it appears that lacosamide pharmacokinetics may be altered in severe renal dysfunction, in patients on dialysis and with extremes of age. More evidence is currently needed on lacosamide pharmacokinetics in pregnancy and critical illness. While it is not practical to utilize TDM for all patients, TDM may be useful in patients taking enzyme-inducer AEDs, in patients with decreased renal function or on dialysis, and older adults.

Electrocardiographic changes associated with epilepsy beyond heart rate and their utilization in future seizure detection and forecasting methods

The ability to assess seizure risk may help provide timely warnings and more personalized treatment plans for people with epilepsy (PWE). ECG changes are commonly observed in epilepsy which make ECG a promising candidate to monitor seizure risk. Most ECG research in this domain has focused on heart rate-related changes. However, several studies have identified a range of other peri-ictal ECG parameter changes that may potentially prove useful for seizure detection and forecasting. Here, we offer a systematic review of ECG changes in epilepsy outside of heart rate. We performed the systematic literature review according to PRISMA guidelines using key words related to ECG, SUDEP and epilepsy. We identified and screened 502 abstracts, read 110 full papers, and included 24 papers in the final review. Our results suggest that PWE may be more prone to cardiac conduction abnormalities than healthy controls. During interictal periods, PWE were more likely to have abnormal QTc intervals, ST segment abnormalities, elevated T Waves, early repolarization (ER), increased P Wave dispersion and PR intervals when compared to controls. Apart from these baseline abnormalities, changes during the pre-ictal and ictal states have been reported, with arrhythmias, QTc prolongation and ST segment changes being the most common. A better understanding of these state-dependent changes may afford less-cumbersome and less-stigmatizing epilepsy monitoring tools in the future.

Antiseizure medications in critical care: an update

PURPOSE OF REVIEW

Seizures and status epilepticus are very common diagnoses in the critically ill patient and are associated with significant morbidity and mortality. There is an abundance of research on the utility of antiseizure medications in this setting, but limited randomized-controlled trials to guide the selection of medications in these patients. This review examines the current guidelines and treatment strategies for status epilepticus and provides an update on newer antiseizure medications in the critical care settings.

RECENT FINDINGS

Time is brain applies to status epilepticus, with delays in treatment corresponding with worsened outcomes. Establishing standardized treatment protocols within a health system, including prehospital treatment, may lead to improved outcomes. Once refractory status epilepticus is established, continuous deep sedation with intravenous anesthetic agents should be effective. In cases, which prove highly refractory, novel approaches should be considered, with recent data suggesting multiple recently approved antiseizure medications, appropriate therapeutic options, as well as novel approaches to upregulate extrasynaptic γ-aminobutyric acid channels with brexanolone.

SUMMARY

Although there are many new treatments to consider for seizures and status epilepticus in the critically ill patient, the most important predictor of outcome may be rapid diagnosis and treatment. There are multiple new and established medications that can be considered in the treatment of these patients once status epilepticus has become refractory, and a multidrug regimen will often be necessary.

Differential association of subtypes of epileptiform activity with outcome after cardiac arrest

BACKGROUND

Epileptiform activity is common after cardiac arrest, although intensity of electroencephalographic (EEG) monitoring may affect detection rates. Prior work has grouped these patterns together as "malignant," without considering discrete subtypes. We describe the incidence of distinct patterns in the ictal-interictal spectrum at two centers and their association with outcomes.

METHODS

We analyzed a retrospective cohort of comatose post-arrest patients admitted at two academic centers from January 2011 to October 2014. One center uses routine continuous EEG, the other acquires "spot" EEG at the treating physicians' discretion. We reviewed all available EEG data and classified epileptiform patterns. We abstracted antiepileptic drugs (AEDs) administrations from the electronic medical record. We compared apparent incidence of each pattern between centers, and compared outcomes (awakening from coma, survival to discharge, discharge modified Rankin Scale (mRS) 0-2) across EEG patterns and number of AEDs administered.

RESULTS

We included 818 patients. Routine continuous EEG was associated with a higher apparent incidence of polyspike burst-suppression (25% vs 13% P < 0.001). Frequency of other epileptiform findings did not differ. Among patients with any epileptiform pattern, only 2/258 (1%, 95%CI 0-3%) were discharged with mRS 0-2, although 24/258 (9%, 95%CI 6-14%) awakened and 36/258 (14%, 95%CI 10-19%) survived. The proportions that awakened and survived decreased in a stepwise manner with progressively worse EEG patterns (range 38% to 2% and 32% to 7%, respectively). Among patients receiving ≥3 AEDs, only 5/80 (6%, 95%CI 2-14%) awakened and 1/80 (1%, 95%CI 0-7%) had a mRS 0-2.

CONCLUSION

We found high rates of epileptiform EEG findings, regardless of intensity of EEG monitoring. The association of distinct ictal-interictal EEG findings with outcome was variable.

Status epilepticus developing during lacosamide monotherapy

Two cases with partial onset epilepsy who developed status epilepticus (SE) on lacosamide (LCM) monotherapy are reported. LCM is an effective adjunctive antiepileptic drug (AED) for partial-onset epilepsy and as infusion in SE. It has also shown efficacy in monotherapy. The reported cases achieved control of seizures with adjunctive LCM treatment and were afterwards converted to monotherapy. Both patients subsequently developed SE while on LCM monotherapy. They were on monotherapy for at least 2 months after withdrawal of concomitant AEDs precluding the possibility of withdrawal-induced SE. Pharmacovigilance is indicated when LCM is administered in monotherapy in order to assess its proper therapeutic potential and its putative limitations especially in cases where it may prove ineffective. Moreover, vigilance is necessary whenever any concomitant antiepileptic is tapered regardless of the substances used. Higher doses may be needed when an AED is used in monotherapy.