Antiepileptic drug interactions

Improving antiepileptic drug tolerability among patients living with epilepsy: the impact of pharmaceutical care services

Therapeutic management of epilepsy is usually long term; thus, patient tolerability of prescribed antiepileptic drugs should be a major consideration as it affects compliance to therapy. The aim of this study was to determine the impact of pharmaceutical care services on antiepileptic drug tolerability among patients living with epilepsy. This study was an open, randomized, controlled, longitudinal and two-arm parallel prospective study with a 6-month patient follow-up period. Patients were recruited from the neurology and medical out-patient clinics of two selected epilepsy referral centres. Recruited patients were randomized into one of the two study groups: pharmaceutical care (PC) or usual care (UC) groups. Patients in the UC group received the usual care provided in the hospitals, while patients in the PC group received PC services in addition to the usual care provided in the hospitals. The impact of PC on patient tolerability of antiepileptic drugs was evaluated using a patient judged antiepileptic drug tolerabiltity scale. The evaluation was done at baseline (pre-intervention), 3 months and 6 months post-intervention. Patients in the PC group had a significantly lower antiepileptic drug tolerability score than those of the UC group at 3 months and 6 months - (Pre-intervention: 0.97 versus 1.13; t = -1.081; p = 0.281), (3 months: 1.13 versus 0.71; t = 3.084; p = 0.001), (6 months: 1.00 versus 0.60; t = 3.083; p = 0.001), indicating a significant improvement in the tolerability of antiepileptic drugs among those in the PC group over time. Pharmaceutical care interventions that included education and counseling services significantly improved tolerability of antiepileptic drugs among patients living with epilepsy.

Insight on the hub gene associated signatures and potential therapeutic agents in epilepsy and glioma

OBJECTIVE

The relationship between epilepsy and glioma has long been widely recognized, but the mechanisms of interaction remain unclear. This study aimed to investigate the shared genetic signature and treatment strategies between epilepsy and glioma.

METHODS

We subjected hippocampal tissue samples from patients with epilepsy and glioma to transcriptomic analysis to identify differential genes and associated pathways, respectively. Weight gene co-expression network (WGCNA) analysis was performed to identify conserved modules in epilepsy and glioma and to obtain differentially expressed conserved genes. Prognostic and diagnostic models were built using lasso regression. We also focused on building transcription factor-gene interaction networks and assessing the proportion of immune invading cells in epilepsy patients. Finally, drug compounds were inferred using a drug signature database (DSigDB) based on core targets.

RESULTS

We discovered 88 differently conserved genes, most of which are involved in synaptic signaling and calcium ion pathways. We used lasso regression model to reduce 88 characteristic genes, and finally screened out 14 genes (EIF4A2, CEP170B, SNPH, EPHA4, KLK7, GNG3, MYOP, ANKRD29, RASD2, PRRT3, EFR3A, SGIP1, RAB6B, CNNM1) as the features of glioma prognosis model whose ROC curve is 0.9. Then, we developed a diagnosis model for epilepsy patients using 8 genes (PRRT3, RASD2, MYPOP, CNNM1, ANKRD29, GNG3, SGIP1, KLK7) with area under ROC curve (AUC) values near 1. According to the ssGSEA method, we observed an increase in activated B cells, eosinophils, follicular helper T cells and type 2T helper cells, and a decrease in monocytes in patients with epilepsy. Notably, the great majority of these immune cells showed a negative correlation with hub genes. To reveal the transcriptional-level regulation mechanism, we also built a TF-gene network. In addition, we discovered that patients with glioma-related epilepsy may benefit more from gabapentin and pregabalin.

CONCLUSION

This study reveals the modular conserved phenotypes of epilepsy and glioma and constructs effective diagnostic and prognostic markers. It provides new biological targets and ideas for the early diagnosis and effective treatment of epilepsy.

The effect of nonadherence on phenobarbital concentrations and recommendations on the replacement dose using Monte Carlo simulation

OBJECTIVES

To determine the impacts of missed phenobarbital (PB) doses on its pharmacokinetics and to investigate the appropriate replacement dosing scheme for various PB missed dose scenarios.

METHODS

Monte Carlo simulations were performed using parameters from the selected population pharmacokinetic study. The impacts of missed PB dose and the proper replacement dosing scheme were assessed based on the percent deviation of simulated concentrations outside the reference range from the full adherence scenario.

RESULTS

The impact of missed PB dose on its concentrations depended on the daily dose. The replacement with a respective regular dose and one and a half regular dose was appropriate for the one and two missed doses scenarios for patients receiving PB monotherapy. For patients receiving PB with valproic acid or phenytoin, the same replacement scheme was still appropriate. The results also indicated that weight did not influence the proper replacement dosing scheme.

CONCLUSIONS

The impacts of missed PB doses on its pharmacokinetics were identified and the proper replacement dosing schemes for different missed dose scenarios were proposed. These schemes should be implemented based on the clinician's justification of the patient's seizure control.

The effect of nonadherence on phenobarbital concentrations and recommendations on the replacement dose using Monte Carlo simulation

OBJECTIVES

To determine the impacts of missed phenobarbital (PB) doses on its pharmacokinetics and to investigate the appropriate replacement dosing scheme for various PB missed dose scenarios.

METHODS

Monte Carlo simulations were performed using parameters from the selected population pharmacokinetic study. The impacts of missed PB dose and the proper replacement dosing scheme were assessed based on the percent deviation of simulated concentrations outside the reference range from the full adherence scenario.

RESULTS

The impact of missed PB dose on its concentrations depended on the daily dose. The replacement with a respective regular dose and one and a half regular dose was appropriate for the one and two missed doses scenarios for patients receiving PB monotherapy. For patients receiving PB with valproic acid or phenytoin, the same replacement scheme was still appropriate. The results also indicated that weight did not influence the proper replacement dosing scheme.

CONCLUSIONS

The impacts of missed PB doses on its pharmacokinetics were identified and the proper replacement dosing schemes for different missed dose scenarios were proposed. These schemes should be implemented based on the clinician's justification of the patient's seizure control.

Levetiracetam-associated irritability and potential role of vitamin B6 use in veterans with epilepsy

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Behavioral adverse effects can limit use of levetiracetam, particularly in Veteran populations.

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Vitamin B6 supplementation has been suggested to reduce irritability.

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22 Veterans were supplemented with vitamin B6 for levetiracetam-associated irritability.

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20 (91%) of Veterans had data regarding irritability.

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9 (45%) Veterans noted improvement in irritability with supplementation.

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11 (55%) Veterans noted no improvement.

Objectives

Levetiracetam, a commonly prescribed antiseizure medication (ASM), may cause irritability, depression, and anger. The mechanisms underlying these behavioral effects and individual risk factors remain unknown. Mitigation strategies are limited, including discontinuation, supplementation with vitamin B6, or switching to an alternative ASM. Several retrospective studies and anecdotal reports, primarily in pediatric populations, suggest vitamin B6 supplementation may be helpful in reducing levetiracetam-associated irritability. Although data in adult patients is limited, and no data is available for Veterans. The objective of this project was to describe our preliminarily experience with vitamin B6 supplementation for alleviating levetiracetam-associated irritability in male Veterans with epilepsy.

Methods

Retrospective chart reviews were completed for patients who had an active prescription for levetiracetam from the William S. Middleton Memorial Veterans Hospital from January 1, 2015 to June 1, 2020. A total of 26 charts were screened. Patients were excluded if not using vitamin B6 supplementation or if deceased at end of data collection. Baseline characteristics were compared, including age, sex, comorbidities, and concomitant medications. Charts were then reviewed to identify any clinical description of irritability, including subjective assessment of change in symptoms across multiple visits, and scores from standardized instruments including the patient health questionnaire (PHQ-9), generalized anxiety disorder questionnaire (GAD-7), and/or irritability in adult patients with epilepsy (I-EPI) questionnaire. These symptoms and scores were then compared pre- and post-B6 supplementation.

Results

Of 22 patients, data was available for 20 (91%). For patients with data available, 9 (45%) showed improved irritability following supplementation with vitamin B6 and 11 (55%) showed no improvement.

Conclusions

This project suggests that vitamin B6 supplementation may have a role in mitigating levetiracetam-associated irritability in a male Veteran population. These results support future prospective controlled studies to assess further the efficacy of this approach and characteristics associated with successful treatment in veterans.

Burden of illness of trigeminal neuralgia among patients managed in a specialist center in England

Background

Trigeminal neuralgia (TN) causes severe episodic, unilateral facial pain and is initially treated with antiepileptic medications. For patients not responding or intolerant to medications, surgery is an option.

Methods

In order to expand understanding of the pain-related burden of illness associated with TN, a cross-sectional survey was conducted of patients at a specialist center that utilizes a multidisciplinary care pathway. Participants provided information regarding their pain experience and treatment history, and completed several patient-reported outcome (PRO) measures.

Results

Of 129 respondents, 69/128 (54%; 1 missing) reported no pain in the past 4 weeks. However, 84 (65%) respondents were on medications, including 49 (38%) on monotherapy and 35 (27%) on polytherapy. A proportion of patients had discontinued at least one medication in the past, mostly due to lack of efficacy (n = 62, 48%) and side effects (n = 51, 40%). A total of 52 (40%) patients had undergone surgery, of whom 30 had microvascular decompression (MVD). Although surgery, especially MVD, provided satisfactory pain control in many patients, 29% of post-surgical patients reported complications, 19% had pain worsen or stay the same, 48% were still taking pain medications for TN, and 33% reported new and different facial pain.

Conclusions

In most PRO measures, respondents with current pain interference had poorer scores than those without pain interference. In the Patient Global Impression of Change, 79% expressed improvement since beginning of treatment at this clinic. These results indicate that while the multidisciplinary approach can substantially alleviate the impact of TN, there remains an unmet medical need for additional treatment options.

Infrequent Monitoring of the Effects of Valproate and Carbamazepine Therapy in Patients With Epilepsy in Nigeria

Background

Carbamazepine and valproate are widely used in the treatment of epileptic seizures. However, these agents exhibit certain adverse effects including hematopoietic disorders (carbamazepine) and severe hepatotoxicity (valproate).

Purpose

To determine the extent of monitoring of the hematologic effects of carbamazepine as well as the extent of monitoring of the hepatic effects of valproate in patients with epilepsy receiving treatment with these agents.

Method

A cross-sectional antiepileptic drug use study using case notes of patients with epilepsy managed at the neurologic clinics of 2 tertiary medical facilities in Nigeria between January and December 2017.

Results

Carbamazepine was the most frequently prescribed antiepileptic drug (48.24%), followed by valproate (29.34%) and levetiracetam (9.24%). Pretreatment monitoring of hematologic effect was carried out in only 61.11% of patients placed on carbamazepine therapy while follow-up monitoring was done in 3.7% of these patients. Also, in patients placed on valproate therapy, pretreatment and follow-up monitoring of the hepatic effect was done in only 33.71% and 19.0% of the patients, respectively.

Conclusions

The extent of monitoring of the hematologic effects of carbamazepine, as well as the hepatic effects of valproate in the cohort studied, is poor.

Differences in knowledge about epilepsy and antiepileptic drugs among pharmacy-dispensing workers in Cambodia and in Lao PDR

Epilepsy is the most common neurological disorder encountered in primary care in Southeast Asia. People with epilepsy require long-term therapy management. Nonadherence to antiepileptic drugs (AEDs) has been identified as a major factor in suboptimal control of epilepsy. Pharmacies offer patients a first-line point of contact with the healthcare system. Many pharmacies operate with limited or nonqualified human resources that can lead to insufficient knowledge, inappropriate supply of medicines, and insufficient counseling.

OBJECTIVE

The aim of this study was to evaluate the qualification and knowledge concerning epilepsy and AEDs among pharmacy-dispensing workers who sell drugs to people with epilepsy.

METHOD

A cross-sectional qualitative study was conducted in public and private pharmacies, in both urban and rural areas of Cambodia and Lao People's Democratic Republic (Lao PDR). The knowledge was collected through a questionnaire.

RESULTS

A total of 180 respondents from 123 outlets in the two countries were included in this study. A proportion of 40.8% (31) of respondents in Cambodia and 38.5% (40) in Lao PDR were pharmacists, followed by sellers who did not received any healthcare training with a proportion of 18.4% (14) in Cambodia compared to 20.2% (21) in Lao PDR. Head trauma was cited as the main cause of epilepsy by 72.4% (55) in Cambodia and 27.2% (28) in Lao PDR (p < 0.001). Epilepsy was considered as a contagious disease by 6.6% (5) of respondents in Cambodia compared to 18.4% (19) in Lao PDR (p = 0.03). Eighty-seven percent (66) of respondents in Cambodia knew at least one long-term AED versus 67.3% (70) in Lao PDR (p = 0.003). Phenobarbital was mentioned in more than 90.0% of cases in both countries. In overall, 15.4% (21) thought that if seizures are controlled for some months, people with epilepsy could stop taking their AEDs. Only one respondent from Lao PDR was aware of drug-drug interaction between AEDs and oral contraception.

CONCLUSION

An educational intervention should be implemented to improve the knowledge of epilepsy and AEDs for pharmacy-dispensing workers. This could include advice for all pharmacy-dispensing workers in order to improve AED management and follow-up of therapeutic adherence.

Pharmacological Treatment of Epilepsy in Elderly Patients

The incidence and prevalence of epilepsy are highest in elderly people, and the etiologies of epilepsy in the elderly differ from those in other age groups. Moreover, diagnosing and treating epilepsy in elderly people may be challenging due to differences in clinical characteristics and physiological changes associated with aging. This review focuses on the pharmacological treatment of epilepsy in elderly patients.

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.

Review about gabapentin misuse, interactions, contraindications and side effects

The current work is targeted to review the risks of gabapentin misuse, its potential interactions with other drugs, side effects and use contraindications. This review consists of a total of 99 biographical references (from the year 1983 to 2016). A publication search of PubMed was performed from January 1983 to December 2016. It included animal studies, clinical studies, case studies and reviews related to gabapentin misuse, potential interactions, side effects and use contraindications. The search terms were gabapentin, anticonvulsant and antiepileptic. In general, it seems that gabapentin has risks of being misused based on the increased level of prescriptions, related fatalities, recreational misuse and higher doses of self-administration. The main reasons for gabapentin misuse are as follows: getting high, alleviating opioid withdrawal symptoms and potentiating methadone effects. Some of the main substances that interact with gabapentin are morphine, caffeine, losartan, ethacrynic acid, phenytoin, mefloquine and magnesium oxide. Some of the side effects caused by gabapentin are teratogenicity, hypoventilation, respiratory failure and myopathy. Finally, reports in general contraindicate the use of gabapentin in conditions such as myasthenia gravis and myoclonus.

Review: Cav2.3 R-type Voltage-Gated Ca2+ Channels - Functional Implications in Convulsive and Non-convulsive Seizure Activity

Background:

Researchers have gained substantial insight into mechanisms of synaptic transmission, hyperexcitability, excitotoxicity and neurodegeneration within the last decades. Voltage-gated Ca²⁺ channels are of central relevance in these processes. In particular, they are key elements in the etiopathogenesis of numerous seizure types and epilepsies. Earlier studies predominantly targeted on Ca_v2.1 P/Q-type and Ca_v3.2 T-type Ca²⁺ channels relevant for absence epileptogenesis. Recent findings bring other channels entities more into focus such as the Ca_v2.3 R-type Ca²⁺ channel which exhibits an intriguing role in ictogenesis and seizure propagation. Ca_v2.3 R-type voltage gated Ca²⁺ channels (VGCC) emerged to be important factors in the pathogenesis of absence epilepsy, human juvenile myoclonic epilepsy (JME), and cellular epileptiform activity, e.g. in CA1 neurons. They also serve as potential target for various antiepileptic drugs, such as lamotrigine and topiramate.

Objective:

This review provides a summary of structure, function and pharmacology of VGCCs and their fundamental role in cellular Ca²⁺ homeostasis. We elaborate the unique modulatory properties of Ca_v2.3 R-type Ca²⁺ channels and point to recent findings in the proictogenic and proneuroapoptotic role of Ca_v2.3 R-type VGCCs in generalized convulsive tonic–clonic and complex-partial hippocampal seizures and its role in non-convulsive absence like seizure activity.

Conclusion:

Development of novel Ca_v2.3 specific modulators can be effective in the pharmacological treatment of epilepsies and other neurological disorders.

Dental care in patients with epilepsy: a survey of 82 patients and their attending dentists and neurologists in southern Germany

INTRODUCTION

The current study assessed the knowledge and attitudes of dentists and neurologists, and of their patients with epilepsy, in the catchment area of an outpatient clinic for epilepsy in southern Germany.

METHODS

One-hundred patients with epilepsy were asked to complete questionnaires about their dental treatment. Attitudes of their attending dentists and neurologists were also assessed.

RESULTS

Patients with epilepsy: The questionnaires were returned by 82% of patients. Of these, 84% regularly (once or twice a year) sought out a dentist, 79% reported their epilepsy to the dentist, 6% were refused treatment by a dentist because of their epilepsy, 10% had already experienced a seizure while at a dental office and 52% wished for more detailed information pretreatment. Dentists: Although 97% treated patients with epilepsy, 21% believed that their equipment was inappropriate for treating a patient experiencing seizures. The majority were not familiar with interactions between antibiotics/analgetics and anti-epileptic drugs. Short-term general anaesthesia was preferred for critical patients by 70% of dentists, 70% recommended dental ceramic for prosthetic reconstruction of anterior teeth and 64% would not recommend use of a removable denture. Neurologists: Sixty-two per cent were asked for advice by their patients, 71% knew about particular risks and interactions between antibiotics/analgetics and anti-epileptic drugs, 8% would stop valproic acid before extensive dental intervention and 92% recommended general anaesthesia in critical patients (uncooperative patients, patients with learning difficulties, and patients with frequent generalised tonic-clonic or complex partial seizures).

DISCUSSION

In general, patients were satisfied with their dental treatment. Regarding the clinician's role, however, dentists need to know more with respect to treating patients with seizures. Beyond that, it would be desirable for neurologists to take more time to answer their patients' questions regarding dental care.

Enzyme-inducing antiepileptic drugs and fractures in people with epilepsy: A systematic review

OBJECTIVE

People with epilepsy (PWE) have an increased fracture risk, independent of seizures. Antiepileptic drugs are thought to increase this risk, particularly those that induce the hepatic cytochrome P450 enzyme system. We aimed to determine whether PWE treated with enzyme-inducing antiepileptic drugs (EIAEDs) have decreased bone mineral density (BMD), or increased fracture incidence, versus those treated with non-EIAEDs.

METHODS

We searched MedLine, EMBase, CENTRAL, and CINAHL prior to November 2014 for all studies comparing fracture risk, or BMD change, in PWE treated for ≥ 1 year with EIAEDs versus non-EIAEDs.

RESULTS

Thirteen observational studies met eligibility criteria. These studies, representing 68,973 adult PWE, were significantly heterogeneous, making meta-analysis impossible. Study results were split, with 5 studies showing decreased BMD in EIAED users, 5 studies showing no effect of EIAED on BMD, 2 studies showing increased fracture incidence in EIAED users, and 1 study showing no difference in fracture risk. The largest study (n = 63,259), which was also the most methodologically rigorous, showed an increased hazard ratio of 9-22% for any fracture, and 49-53% for hip fracture, in EIAED users.

SIGNIFICANCE

The literature is divided regarding the bone effects of EIAEDs; however, current best evidence supports an increased fracture risk in PWE treated with an EIAED compared to those treated with non-EIAEDs. A single article dominated our review, and other large methodologically rigorous studies are needed to confirm or refute its results. Further small studies, with limited power to control for multiple potentially confounding variables, are not likely to help.

The clinical significance of drug interactions between dermatological and psychoactive medications

Dermatological disease is commonly associated with psychological morbidity because of its visible nature. The burden of living with a chronic dermatological illness can contribute to the development of psychiatric illness and conversely, such conditions can result in the exacerbation of preexisting dermatological disease. It may also reduce a patient's compliance to treatment, result in loss to follow-up and a decreased level of functioning and quality of life. In dermatological patients who suffer from psychiatric symptoms, medical management used in their treatment may have significant interactions with systemic medications used to treat their dermatological condition. A well-known example of this is lithium's ability to exacerbate psoriasis. Such interactions can result in suboptimal treatment of their psychiatric and/or dermatological condition. The present paper aimed to review the literature for documented interactions and the level of clinical significance between dermatological and psychoactive medications. Such information is clinically relevant to the practicing dermatologist in order to minimize adverse effects and drug-drug interactions in dermatological patients.

Clinically significant psychotropic drug-drug interactions in the primary care setting

In recent years, the growing numbers of patients seeking care for a wide range of psychiatric illnesses in the primary care setting has resulted in an increase in the number of psychotropic medications prescribed. Along with the increased utilization of psychotropic medications, considerable variability is noted in the prescribing patterns of primary care providers and psychiatrists. Because psychiatric patients also suffer from a number of additional medical comorbidities, the increased utilization of psychotropic medications presents an elevated risk of clinically significant drug interactions in these patients. While life-threatening drug interactions are rare, clinically significant drug interactions impacting drug response or appearance of serious adverse drug reactions have been documented and can impact long-term outcomes. Additionally, the impact of genetic variability on the psychotropic drug's pharmacodynamics and/or pharmacokinetics may further complicate drug therapy. Increased awareness of clinically relevant psychotropic drug interactions can aid clinicians to achieve optimal therapeutic outcomes in patients in the primary care setting.

Impaired verbal fluency under topiramate--evidence for synergistic negative effects of epilepsy, topiramate, and polytherapy

BACKGROUND AND PURPOSE

Treatment with topiramate (TPM) is known to negatively affect executive functions and verbal fluency in particular. However, judgments of cognitive side effects under TPM rarely consider clinical conditions and possible effects of epilepsy, treatment, and drug load.

METHODS

This retrospective cross-sectional study in large cohorts of patients with epilepsy evaluated the impact of TPM mono- and polytherapy on verbal fluency. To isolate TPM-induced effects from those of epilepsy and antiepileptic medication in general, verbal fluency under TPM (N = 421) was compared to the performance of a matched sample of patients with an antiepileptic medication other than TPM (N = 351), untreated patients (N = 108), and healthy controls (N = 100).

RESULTS

Impaired verbal fluency performance was seen in 77% of the patients treated with TPM. Compared to healthy controls, verbal fluency in untreated patients was reduced by 22%, under monotherapy without TPM by 31% and under TPM monotherapy by 45%. With and without TPM, verbal fluency performance linearly decreased with each additional drug in polytherapy. On each level, performance under TPM was 21-28% worse than in the respective condition without TPM. Unimpaired performance under TPM was primarily associated with lower dose, higher education, and a later onset of epilepsy.

CONCLUSIONS

The majority of patients under TPM shows reduced verbal fluency. However, when taking the cumulative negative effects of epilepsy, and the concomitant drug regimen into account, TPM is associated with a 21-28% poorer performance as compared with other drugs. Additionally, the data indicate an impact of dose and reserve capacity on the occurrence of impairments.

Levetiracetam is associated with improved cognitive outcome for patients with intracranial hemorrhage

BACKGROUND

To date, common therapy in patients with intracranial hemorrhage (ICH) includes prophylaxis of seizure using antiepileptic drugs, commonly phenytoin. Phenytoin therapy is associated with a high incidence of cognitive disturbance. Levetiracetam is known to cause less cognitive disruption and may be a suitable alternative for seizure prophylaxis. Cognitive outcomes in ICH patients receiving seizure prophylaxis with levetiracetam or phenytoin are compared.

METHOD

A retrospective chart review was conducted with 269 patients who received prophylactic levetiracetam or phenytoin between August 2005 and May 2008. A total of 85 reviewed patients met inclusion criteria (phenytoin n = 25, levetiracetam n = 60).

RESULTS

Statistically significant results included higher Glasgow Coma Scores (GCS) at dismissal (median, 14 vs. 11, P = 0.023), lower seizure incidence (0.0 vs. 8%, P = 0.03) for patients receiving levetiracetam than those treated with phenytoin and patients being discharged home (21.7% vs. 16%, P = 0.03). Observed trends included greater cognitive function retention rate (56.7% vs. 36%, P = 0.08).

CONCLUSION

Despite similarities in hemorrhage type and severity at onset, patients receiving levetiracetam had better cognition at discharge and fewer seizures than patients receiving phenytoin. These data suggest that levetiracetam is more effective than phenytoin for seizure prophylaxis without suppression of cognitive abilities in patients with ICH.

Levetiracetam for the treatment of alcohol withdrawal syndrome: a multicenter, prospective, randomized, placebo-controlled trial

BACKGROUND

Treatment of alcohol withdrawal syndrome (AWS) with benzodiazepines is limited by risk of abuse, intoxication, respiratory problems, and liver toxicity. Alternatives such as carbamazepine and valproate may also have safety problems, such as hepatotoxicity or central nervous adverse effects. We therefore investigated the safety and efficacy of levetiracetam (LV), a newer antiepileptic with a potentially favorable adverse-effect profile, for the treatment of AWS.

METHODS

One hundred six patients were enrolled in a prospective, randomized, double-blind, multicenter, placebo-controlled trial. Levetiracetam was administered in a fixed dose schedule over 6 days. Diazepam was added when symptom triggered as rescue medication. Severity of the AWS was measured with the AWS and Clinical Institute Withdrawal Assessment Scale.

RESULTS

Although tolerability and safety data were similar in the LV group when compared with placebo, the total daily and weekly dose of diazepam as rescue medication and the severity of alcohol withdrawal symptoms did not differ significantly between groups.

CONCLUSION

Our data so far do not support an additional effect of LV on the reduction of alcohol withdrawal symptoms.

Effectiveness of the association between carbamazepine and peripheral analgesic block with ropivacaine for the treatment of trigeminal neuralgia

Treatment of trigeminal neuralgia (TN) is achieved by using adjuvant analgesics like antiepileptics, with carbamazepine (CBZ) being the first-line approach for TN patients, although side effects may be present. Other approaches using gabapentin, namely when associated with peripheral analgesic block of TN trigger points with the local anesthetic ropivacaine (ROP), resulted in decreased pain and daily drug intake (reduced side effects). This study evaluates if the association between CBZ and the peripheral block with ROP reinforces the clinical value of CBZ. In this parallel, double-blinded study, idiopathic TN patients were randomized to receive during 4 weeks either CBZ (CBZ; n = 21) or CBZ associated with the peripheral analgesic block using ROP (CBZ + ROP; n = 24). The primary outcome measures were the following: i) pain intensity, evaluated by the numerical rating scale; ii) number of pain crises; and iii) number needed to treat. Evaluation points were at the beginning (day 1) and end (day 29) of treatment and after a follow-up of 5 months (month 6). Both protocols resulted in a decrease of pain intensity and number of pain crises, but only the association CBZ + ROP showed i) a significant stronger reduction in pain intensity at month 6 and ii) a significant decrease in the daily dose of CBZ given to patients (both at day 29 and month 6). In contrast, the daily dose in CBZ-only patients remained constant or even increased. The number needed to treat for the association CBZ + ROP over the CBZ protocol reduced from 5 at the end of the 4-week treatment to 3 after the 5-month follow-up. Data reinforce the use of CBZ as a primary tool to control pain in TN patients, as the association CBZ + ROP i) improves the clinical qualities of CBZ, ii) strongly reduces the daily dose of CBZ, and iii) reduces the potential side effects attributed to high doses of CBZ.

Update on the Genetic Polymorphisms of Drug-Metabolizing Enzymes in Antiepileptic Drug Therapy

Genetic polymorphisms in the genes that encode drug-metabolizing enzymes are implicated in the inter-individual variability in the pharmacokinetics and pharmaco-dynamics of antiepileptic drugs (AEDs). However, the clinical impact of these polymorphisms on AED therapy still remains controversial. The defective alleles of cytochrome P450 (CYP) 2C9 and/or CYP2C19 could affect not only the pharmacokinetics, but also the pharmacodynamics of phenytoin therapy. CYP2C19 deficient genotypes were associated with the higher serum concentration of an active metabolite of clobazam, N-desmethylclobazam, and with the higher clinical efficacy of clobazam therapy than the other CYP2C19 genotypes. The defective alleles of CYP2C9 and/or CYP2C19 were also found to have clinically significant effects on the inter-individual variabilities in the population pharmacokinetics of phenobarbital, valproic acid and zonisamide. EPHX1 polymorphisms may be associated with the pharmacokinetics of carbamazepine and the risk of phenytoin-induced congenital malformations. Similarly, the UDP-glucuronosyltransferase 2B7 genotype may affect the pharmacokinetics of lamotrigine. Gluthatione S-transferase null genotypes are implicated in an increased risk of hepatotoxicity caused by carbamazepine and valproic acid. This article summarizes the state of research on the effects of mutations of drug-metabolizing enzymes on the pharmacokinetics and pharmacodynamics of AED therapies. Future directions for the dose-adjustment of AED are discussed.

Carbamazepine but not valproate induces CYP2A6 activity in smokers with mental illness

BACKGROUND

Antiepileptic drugs (AED) are being increasingly used in the management of serious mental illness, but their effects on nicotine metabolism have not been studied.

METHODS

This study investigated the effects of three AEDs (carbamazepine, oxcarbazepine, and valproic acid) on nicotine and nicotine metabolite levels in 149 smokers with schizophrenia and bipolar disorder who participated in an afternoon blood draw for nicotine, cotinine, and 3'-hydroxycotinine (3HC). The ratio of 3HC to cotinine was calculated as a marker of CYP2A6 metabolic activity. Among the participants, 8 smokers were taking carbamazepine, 6 were taking oxcarbazepine, and 40 were taking valproic acid.

RESULTS

The 3HC/cotinine ratio was significantly higher in individuals taking carbamazepine or oxcarbazepine (combined, n = 14) versus those not taking either (mean 0.993 versus 0.503; P < 0.001). The cotinine/cigarette per day ratio was significantly lower in individuals taking carbamazepine or oxcarbazepine. The 3HC/cotinine ratios were also significantly higher in the subgroup of individuals taking carbamazepine (n = 8) versus those not taking it. There were no significant differences in nicotine or cotinine levels or 3HC/cotinine ratios in individuals taking valproic acid versus those not taking it. We conducted backward stepwise linear regression models to identify predictors of the log transformed 3HC/cotinine ratios. Taking carbamazepine and number of cigarettes smoked per day were significant determinants of log 3HC/cotinine.

CONCLUSIONS

Carbamazepine likely induces hepatic metabolism via CYP2A6 and is associated with increased 3HC/cotinine ratios.

IMPACT

Increased nicotine metabolism in individuals using AED has implications for increased smoking behavior and exposure to more tobacco toxins, which warrants further study.

Anticoagulation and psychotropic medications

Anticoagulants and psychotropic medications are commonly prescribed together. Thus, the potential for interaction exists. Whereas thrombolytics and heparins are implicated in few pharmacokinetic interactions, warfarin and platelet inhibitors have been implicated in various interactions with psychotropic medications. In this article, I review the various psychotropic drug classes' relationships to anticoagulants. In a field devoid of randomized, placebo-controlled trials, clinical vigilance is advised when managing patients on concomitant therapy.

Truly "rational" polytherapy: maximizing efficacy and minimizing drug interactions, drug load, and adverse effects

While several newer AEDs have study data that support monotherapy usage, most possess FDA indications for adjunctive treatment of partial onset seizures, leading to their initial (and often persistent) clinical use as adjunctive polytherapy for patients with refractory epilepsy. This review considers a practical approach to the appropriate role for polytherapy in epilepsy, presents the evidence for AED polytherapy, reviews the mythic but practically reasonable concept of "rational polytherapy," and concludes with practical strategies for avoiding and employing polytherapy in clinical practice. The appropriate indications for AED polytherapy include transitional polytherapy during titration of a new adjunctive AED toward monotherapy or long-term maintenance AED polytherapy in medically refractory epilepsy.