Antiepileptic Drug Removal by Continuous Renal Replacement Therapy: A Review of the Literature

Personalized antiseizure medication therapy in critically ill adult patients

Precision medicine has the potential to have a significant impact on both drug development and patient care. It is crucial to not only provide prompt effective antiseizure treatment for critically ill patients after seizures start but also have a proactive mindset and concentrate on epileptogenesis and the underlying cause of the seizures or seizure disorders. Critical illness presents different treatment issues compared with the ambulatory population, which makes it challenging to choose the best antiseizure medications and to administer them at the right time and at the right dose. Since there is a paucity of information available on antiseizure medication dosing in critically ill patients, therapeutic drug monitoring is a useful tool for defining each patient's personal therapeutic range and assisting clinicians in decision-making. Use of pharmacogenomic information relating to pharmacokinetics, hepatic metabolism, and seizure etiology may improve safety and efficacy by individualizing therapy. Studies evaluating the clinical implementation of pharmacogenomic information at the point-of-care and identification of biomarkers are also needed. These studies may make it possible to avoid adverse drug reactions, maximize drug efficacy, reduce drug-drug interactions, and optimize medications for each individual patient. This review will discuss the available literature and provide future insights on precision medicine use with antiseizure therapy in critically ill adult patients.

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.

Individualizing doses of antiepileptic drugs

INTRODUCTION

This review aims to identify the optimal therapeutic dosage of anti-epileptic drugs in terms of efficacy and safety in patients with multiple comorbidities.

AREAS COVERED

We have analyzed changes in terms of pharmacokinetics and pharmacodynamics of Brivaracetam, Carbamazepine, Lacosamide, Lamotrigine, Levetiracetam, Topiramate, Valproate, and Zonisamide in liver disease, chronic kidney disease, and in patients admitted to intensive care unit. Our literature search covers the past 5 years. We used PubMed, Google Scholar, and EMBASE database's to support our article.

EXPERT OPINION

To ensure that the patient with seizure receives the best treatment in relation to their comorbidities, careful clinical-laboratory monitoring is necessary to maximize effectiveness while maintaining safety, especially in the case of polytherapy.

A Clinician's Guide to Dosing Analgesics, Anticonvulsants, and Psychotropic Medications in Continuous Renal Replacement Therapy

Acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) is a common complication in critical illness and has a significant impact on pharmacokinetic factors determining drug exposure, including absorption, distribution, transport, metabolism, and clearance. In this review, we provide a practical guide to drug dosing considerations in critically ill patients undergoing CRRT, focusing on the most commonly used analgesic, anticonvulsant, and psychotropic medications in the clinical care of critically ill patients. A literature search was conducted to identify articles in which drug dosing was evaluated in adult patients receiving CRRT between the years 1980 and 2020. We included articles with pharmacokinetic/pharmacodynamic analyses and those that described medication clearance via CRRT. A summary of the data focused on practical pharmacokinetic and pharmacodynamic principles is presented, with recommendations for drug dosing of analgesics, anticonvulsants, and psychotropic medications. Pharmacokinetic and pharmacodynamic studies to guide drug dosing of analgesics, anticonvulsants, and psychotropic medications in critically ill patients receiving CRRT are sparse. Considering the widespread use of these medications, narrow therapeutic index of these drug classes, and risks of over- and underdosing, additional studies in patients receiving CRRT are needed to inform drug dosing.

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.

Management of status epilepticus in patients with liver or kidney disease: a narrative review

Introduction: Status epilepticus (SE) is a neurologic and medical emergency with significant related morbidity and mortality. Hepatic or renal dysfunction can considerably affect the pharmacokinetics of drugs used for SE through a variety of direct or indirect mechanisms.Areas Covered: This review aims to focus on the therapeutic management of SE in patients with hepatic or renal impairment, highlighting drugs' selection and dose changes that may be necessary due to altered drug metabolism and excretion. The references for this review were identified by searches of PubMed and Google Scholar until May 2020.Expert opinion: According to literature evidence and clinical experience, in patients with renal disease, the authors suggest considering lorazepam as the drug of choice in pre-hospital and intra-hospital early-stage SE, phenytoin in definite SE, propofol in refractory or super-refractory SE. In patients with liver disease, the authors suggest the use of lorazepam as drug of choice in pre-hospital and intra-hospital early-stage SE, lacosamide in definite SE, propofol in refractory or super-refractory SE. A list of preferred drugs for all SE stages is provided.

Evaluation of tacrolimus and mycophenolic acid removal by simultaneous continuous hemodiafiltration and plasma exchange in a lung transplant patient

WHAT IS KNOWN AND OBJECTIVE

The removal rates of tacrolimus (TAC) and mycophenolic acid (MPA) by simultaneous plasma exchange (PE) and continuous hemodiafiltration (CHDF) are not clear.

CASE SUMMARY

We evaluated the removal rates of TAC and MPA by PE and CHDF started simultaneously 5 hours after administration in a lung transplant patient. TAC was not removed. MPA was transferred into the PE effluent, but the total amount in the effluent was only 1% of the dosage.

WHAT IS NEW AND CONCLUSION

TAC and MPA were less likely to be removed by PE and CHDF initiated 5 hours after administration.

Drug Dosing in Critically Ill Patients with Acute Kidney Injury and on Renal Replacement Therapy

Acute kidney injury (AKI) complicates in around 40-50% of patients in intensive care units (ICUs), and this can account for up to 80% mortality, especially in those patients requiring renal replacement therapy (RRT). Appropriate drug dosing in such patients is a challenge to the intensivists due to various factors such as patient related (appropriate body weight, organ clearance, serum protein concentration), drug related [molecular weight (MW), protein binding, volume of distribution (V d), hydrophilicity, or hydrophobicity], and RRT related (type, modality of solute removal, filter characteristics, dose, and duration). Therapeutic drug monitoring (TDM) of drugs can be a promising solution to this complex scenario to titrate a drug to its clinical response, but it is available only for a few drugs. In this review, we discussed drug dosing aspects of antimicrobials, sedatives, and antiepileptics in critically ill patients with AKI on RRT.

HOW TO CITE THIS ARTICLE

Saran S, Rao NS, Azim A. Drug Dosing in Critically Ill Patients with Acute Kidney Injury and on Renal Replacement Therapy. Indian J Crit Care Med 2020;24(Suppl 3):S129-S134.

Managing the patient with epilepsy and renal impairment

PURPOSE

Epilepsy affects more than 50 million people worldwide and its management can be complicated by comorbidities such as impaired renal function. To optimize epilepsy control in patients with kidney disease, clinicians need to be aware of how antiepileptic drugs (AEDs) are affected by impaired renal function and how the kidneys are affected by epilepsy management strategies. Herein we present a narrative review with systematic literature search to discuss the use of AEDs in patients with renal impairment, including those undergoing dialysis, as well as the nephrotoxic effects of some AEDs. We finally conclude the article by providing practical tips about our approach to using AEDs in the setting of renal disease.

METHODS

A literature search targeting epilepsy management in patients with kidney disease was performed in MEDLINE database (1946 to 7th Jan 2019).

RESULTS

A total of 1193 articles were found. After duplicate removal, title and abstract screening followed by full text screening, a total of 110 references were included in this review. Additional information was included from drug product monographs.

CONCLUSION

The disposition of AEDs can be altered in patients with impaired renal function, leading to a higher risk of AED toxicity or therapy failure. Renal dosage adjustment and close monitoring is recommended. Although AED-induced nephrotoxicity is rare, it is unpredictable and clinicians need to vigilant about this possibility. In addition, AEDs renal adverse reactions and renal drug interactions should be considered when selecting an AED.

Prevention, Treatment, and Monitoring of Seizures in the Intensive Care Unit

The diagnosis and management of seizures in the critically ill patient can sometimes present a unique challenge for practitioners due to lack of exposure and complex patient comorbidities. The reported incidence varies between 8% and 34% of critically ill patients, with many patients often showing no overt clinical signs of seizures. Outcomes in patients with unidentified seizure activity tend to be poor, and mortality significantly increases in those who have seizure activity longer than 30 min. Prompt diagnosis and provision of medical therapy are crucial in order to attain successful seizure termination and prevent poor outcomes. In this article, we review the epidemiology and pathophysiology of seizures in the critically ill, various seizure monitoring modalities, and recommended medical therapy.

Successful treatment of seizure disorder by evaluating phenobarbital clearance in a paediatric patient undergoing continuous haemodiafiltration

WHAT IS KNOWN AND OBJECTIVE

Determination of phenobarbital (PB) dosing during continuous haemodiafiltration (CHDF) requires evaluation of both the patient's own clearance and CHDF clearance.

CASE DESCRIPTION

Systemic clearance of PB in a 9-year-old female patient with Dravet syndrome, who was undergoing CHDF, was calculated by the Sawchuk-Zaske method, and clearance by CHDF was calculated as the difference between PB levels in influx and efflux, adjusted for the blood purification conditions. Dosage adjustment produced seizure control.

WHAT IS NEW AND CONCLUSION

Adjusting PB dose by evaluating the patient's own PB clearance as well as that by CHDF resulted in accurate control of PB level and a reduction in the occurrence of seizures.

Assessing and Treating Chronic Pain in Patients with End-Stage Renal Disease

Pain is one of the most common symptoms among patients with end-stage renal disease (ESRD), and is often under recognized and not adequately managed in hemodialysis (HD) patients. Barriers to adequate pain management include poor awareness of the problem, insufficient medical education, fears of possible drug-related side effects, and common misconceptions about the inevitability of pain in elderly and HD patients. Caregivers working in HD should be aware of the possible consequences of inadequate pain assessment and management. Common pain syndromes in HD patients include musculoskeletal diseases and metabolic neuropathies, associated with typical intradialytic pain. Evaluating the etiology, nature, and intensity of pain is crucial for choosing the correct analgesic. A mechanism-based approach to pain management may result in a better outcome. Pharmacokinetic considerations on clearance alterations and possible toxicity in patients with ESRD should drive the right analgesic prescription. Comorbidities and polymedications may increase the risk of drug-drug interactions, therefore drug metabolism should be taken into account when selecting analgesic drugs. Automedication is common among HD patients but should be avoided to reduce the risk of hazardous drug administration. Further research is warranted to define the efficacy and safety of analgesic drugs and techniques in the context of patients with ESRD as generalizing information from studies conducted in the general population could be inappropriate and potentially dangerous. A multidisciplinary approach is recommended for the management of complex pain syndromes in frail patients, such as those suffering from ESRD.

Antiepileptic drugs in critically ill patients

BACKGROUND

The incidence of seizures in intensive care units ranges from 3.3% to 34%. It is therefore often necessary to initiate or continue anticonvulsant drugs in this setting. When a new anticonvulsant is initiated, drug factors, such as onset of action and side effects, and patient factors, such as age, renal, and hepatic function, should be taken into account. It is important to note that the altered physiology of critically ill patients as well as pharmacological and nonpharmacological interventions such as renal replacement therapy, extracorporeal membrane oxygenation, and target temperature management may lead to therapeutic failure or toxicity. This may be even more challenging with the availability of newer antiepileptics where the evidence for their use in critically ill patients is limited.

MAIN BODY

This article reviews the pharmacokinetics and pharmacodynamics of antiepileptics as well as application of these principles when dosing antiepileptics and monitoring serum levels in critically ill patients. The selection of the most appropriate anticonvulsant to treat seizure and status epileptics as well as the prophylactic use of these agents in this setting are also discussed. Drug-drug interactions and the effect of nonpharmacological interventions such as renal replacement therapy, plasma exchange, and extracorporeal membrane oxygenation on anticonvulsant removal are also included.

CONCLUSION

Optimal management of antiepileptic drugs in the intensive care unit is challenging given altered physiology, polypharmacy, and nonpharmacological interventions, and requires a multidisciplinary approach where appropriate and timely assessment, diagnosis, treatment, and monitoring plans are in place.

Considerations for Medication Management and Anticoagulation During Continuous Renal Replacement Therapy

Providing safe and high-quality care to critically ill patients receiving continuous renal replacement therapy (CRRT) includes adequate drug dosing and evaluation of patients' response to medications during therapy. Pharmacokinetic drug studies in acute kidney injury and CRRT are limited, considering the number of medications used in critical care. Therefore, it is important to understand the basic principles of drug clearance during CRRT by evaluating drug properties, CRRT modalities, and how they affect medication clearance. Few published studies have addressed drug disposition and clinical response during CRRT. Additionally, clotting in the CRRT circuit is a concern, so a few options for anticoagulation strategies are presented. This article reviews (1) the CRRT system and drug property factors that affect medication management, (2) the evidence available to guide drug dosing, and (3) anticoagulation strategies for critically ill patients receiving CRRT.