Pharmacokinetic Interactions between Antiepileptic and Antidepressant Drugs

CYP2D6 gene polymorphism and apatinib affect the metabolic profile of fluvoxamine

This study aimed 1) to investigate the influence of CYP2D6 variants on the catalyzing of fluvoxamine, and 2) to study the interaction between fluvoxamine and apatinib. An enzymatic reaction system was setup and the kinetic profile of CYP2D6 in metabolizing fluvoxamine was determined. In vivo, drug-drug interaction was investigated using Sprague–Dawley (SD) rats. Fluvoxamine was given gavage with or without apatinib. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the concentrations of fluvoxamine and desmethyl-fluvoxamine. The results demonstrated that the relative clearance rates of CYP2D6.A5V, V104A, D337G, F164L, V342M, R440C and R497C increased significantly compared with CYP2D6.1, ranging from 153.626% ± 6.718% to 394.310% ± 33.268%. The activities of other variants reduced to different extent, or even lost function, but there was no statistical difference. The IC₅₀ of apatinib against fluvoxamine disposition was determined, which is 0.190 μM in RLM and 6.419 μM in HLM, respectively. In vivo, apatinib can enhance the plasma exposure of fluvoxamine remarkably characterized by increased AUC, Tmax and Cmax. Meanwhile, the produce of desmethyl fluvoxamine was dramatically inhibited, both AUC and C_max decreased significantly. Mechanistically, apatinib inhibit the generation of fluvoxamine metabolite with a mixed manner both in RLM and HLM. Furthermore, there were differences in the potency of apatinib in suppressing fluvoxamine metabolism among CYP2D6.1, 2 and 10. In conclusion, CYP2D6 gene polymorphisms and drug-drug interaction can remarkably affect the plasma exposure of fluvoxamine. The present study provides basis data for guiding individual application of fluvoxamine.

Topiramate and other kainate receptor antagonists for depression: A systematic review of randomized controlled trials

BACKGROUND

Depression is a common disorder that affects patients' quality of life and incurs health system costs. Due to the resistance to treat depression, better understanding of neurophysiology was considered; one of the implications is the glutamatergic system. This study aims to systematically review clinical trials investigating the antidepressant effects of kainate receptor antagonists.

METHODS

The study protocol was registered in PROSPERO (CRD42021213912). Scopus, ISI, Embase, PubMed, Cochrane Library, Google Scholar, and two trial registries were searched for randomized controlled trials on the effectiveness of topiramate, phenobarbital, and other ten barbiturates in depression. The difference with control groups in terms of changing depressive symptoms was the primary outcome.

RESULTS

Nine trials were identified, in which 784 patients were studied. The efficacy of thiopental was comparable to that of imipramine, with fewer side effects. When administered with electroconvulsive therapy, it had fewer to similar effects and fewer side effects than ketamine. Both monotherapy and adjunctive therapy with topiramate were effective and tolerable in treating depressed patients. Phenobarbital had therapeutic effects compared to imipramine and amitriptyline with fewer side effects.

CONCLUSION

Regarding the glutamatergic hypothesis of depression and obtained promising results, further studies of kainate receptor antagonists in high-quality trials are recommended. Given the high prevalence of depression in epileptic patients, more problems with its treatment, and the fact that the studied agents were anticonvulsants, it is recommended that future studies prioritize depressed-epileptic patients.

Epilepsy and neuropsychiatric comorbidities

Epilepsy is a common neurological condition with wide-ranging neuropsychiatric manifestations. The relationship between epilepsy and psychiatry has been recognised for centuries. However, the wide range of neuropsychiatric comorbidities and their extent is only now beginning to be appreciated. The impact of these comorbidities on patients' help-seeking behaviour, seizure control and quality of life suggests that early detection and treatment are of paramount importance. Clinical issues in relation to accurate recognition and appropriate management of neuropsychiatric conditions in epilepsy are discussed.

Depression in temporal lobe epilepsy: a review of prevalence, clinical features, and management considerations

Depression in temporal lobe epilepsy has been established as a frequent occurrence, and various possible mechanisms for this significant comorbidity have been posited. However, there is still little to guide a clinician in the recognition and management of depression in patients with temporal lobe epilepsy. This is in part due to the lack of consistent findings in earlier studies, which was likely partly due to variabilities in methodology, sampling, and diagnosis of both temporal lobe epilepsy and depression. However, in recent years, significant effort has been made to address these issues and provide a framework for diagnosis and management of depression in this population. The following is a review of the literature, with special emphasis on clinical phenomenology of depressive symptoms, described bidirectional risk between depression and temporal lobe epilepsy, and treatment strategies in the context of potential drug interactions with antiepileptic drugs.

Don't be afraid to treat depression in patients with epilepsy!

Major depression and related depressive disorders are highly prevalent in the general population and even more so in patients with epilepsy. Yet depression in these patients remains underdiagnosed and undertreated. This is particularly worrisome as depression has greater negative impact on quality of life than seizure frequency. Additionally, depression is associated with poorer seizure control, and the risk of suicide in patients with epilepsy is greatly increased. Reluctance to treat depression results from the traditional belief that antidepressants should be restricted in epilepsy because of a supposed decrease in seizure threshold. However, there is growing evidence that many antidepressants rather have anticonvulsant effects. Experimental studies show that in critical brain regions such as the frontal lobes and the limbic system enforced serotonergic circuits increase seizure threshold. Clinical data suggest that modern antidepressants may reduce seizure frequency in patients with pharmacoresistant epilepsy. Here we review the concept that selective reuptake inhibitors of serotonin (SSRIs) have a positive effect on the mood disorder as well as on epilepsy. When adhering to the usual precautions, treatment with SSRIs in patients with epilepsy and depression is safe and should not be withheld.

Psychiatric aspects of epilepsy

Patients who have epilepsy face many challenges resulting from their illness and have frequent psychiatric comorbidities. Recognition of these disorders is increasing and is having a positive impact on patients' quality of life. Recent recommendations about a new classification system for psychiatric disorders related specifically to epilepsy and based on the relationship of symptoms to seizures, antiepileptic medications, and EEG changes should further research and treatment. Especially insofar psychiatric syndromes specific to epilepsy can be identified, correlation of clinical phenomena with relatively well-understood pathophysiology in epilepsy will allow advances in the understanding of psychiatric illness. This progress should move the treatment of patients who have epilepsy toward a comprehensive biopsychosocial model that focuses on the whole person rather than simply on the disease process.

Anxiety in patients with epilepsy: systematic review and suggestions for clinical management

Up to 50 or 60% of patients with chronic epilepsy have various mood disorders including depression and anxiety. Whereas the relationship between epilepsy and depression has received much attention, less is known about anxiety disorders. It is now recognized that anxiety can have a profound influence on the quality of life of patients with epilepsy. The relationship between anxiety disorders and epilepsy is complex. It is necessary to distinguish between different manifestations of anxiety disorder: ictal, postictal, and interictal anxiety. Preexisting vulnerability factors, neurobiological factors, iatrogenic influences (antiepileptic drugs, epilepsy surgery), and psychosocial factors are all likely to play a role, but with considerable individual differences. Despite the high prevalence of anxiety disorders in patients with epilepsy, there are no systematic treatment studies or evidence-based guidelines for best treatment practice. Nevertheless, a practical approach based on the temporal relationship between anxiety and epileptic seizures allows clinicians to consider appropriate treatment strategies to reduce the psychiatric comorbidity in patients with epilepsy.

[Patients with epilepsy and anxiety disorders. Diagnosis and treatment]

Up to 50-60% of patients with epilepsy may develop psychiatric complications, in particular depression, anxiety, and psychotic disorders. Although this comorbidity has received a great deal of attention in recent years, the anxiety spectrum of psychiatric disturbances in epilepsy patients has not been extensively studied, although this comorbidity has a significant effect on the medical management and quality of life. The etiology is multifactorial, including neurobiological and shared pathophysiological mechanisms as well as psychosocial and iatrogenic factors (e.g., influence of antiepileptic drugs, epilepsy surgery). Despite the high prevalence of comorbid anxiety in epilepsy, very little is known about optimal treatment strategies. This article reviews the complex interrelationships between anxiety disorders and epilepsy from a clinical point of view. The evaluation of anxiety relative to ictal, peri-ictal, and postictal states is described, and medical treatment options for anxiety disorders in patients with epilepsy are discussed, illustrating that their treatment extends far beyond seizure control.

[Drug interactions with antiepileptic agents]

Drug interactions with antiepileptic agents are based in large part on pharmacokinetic mechanisms. Most prominent are induction or inhibition of enzymes of the cytochrome P450 (CYP) system, which is of central importance for metabolic elimination of lipophilic xenobiotics. Potent inductors of CYP isoenzymes are carbamazepine, phenobarbital, phenytoin, and primidone, thereby decreasing not only their own plasma levels and efficacy but also that of other antiepileptics and other drugs. Felbamate, oxcarbazepine, and topiramate are weak inductors of the CYP isoenzyme 3A4, whereas they inhibit CYP2C19. Valproic acid is a potent inhibitor of several CYP isoenzymes and glucuronyltransferases, resulting in an increase in plasma concentrations and toxicity of antiepileptics and other drugs. Antiepileptics that are not involved in drug interactions include gabapentin, levetiracetam, and vigabatrine. The P-glycoprotein may mediate the exit of antiepileptics from the brain. This transport mechanism is inhibited by carbamazepine, which may explain the enhanced clinical efficacy of a combination of carbamazepin with other antiepileptics. Other possible pharmacokinetic interactions are precipitation of antiepileptics in the stomach by antacids or sucralfate and displacement from plasmaprotein binding of one antiepileptic agent by another. Therapeutic drug monitoring (TDM) may be helpful in assessing pharmacokinetic drug interactions. Pharmacodynamic interactions appear to be responsible for the enhanced efficacy of antiepileptic combination therapy. In prescribing drugs, their spectrum of interactions has to be known.

The importance of being seizure free: topiramate and psychopathology in epilepsy

The aim of this study was to analyze in detail psychopathology associated with topiramate (TPM) prescription and to analyze the relationship between psychopathology and seizure freedom. We analyzed the data on 103 patients who developed psychiatric disorders during TPM therapy. Forty-six patients developed an affective disorder, 22 aggressive behavior, 16 psychosis, 11 anxiety, and 8 personality changes such as anger, agitation, and hostile behavior. Patients with psychosis were more likely to be seizure-free during psychopathology, to receive psychotropic drug prescription, and to be admitted to hospital. In general, patients seizure-free during psychopathology were more likely to have a diagnosis of idiopathic generalized epilepsy, to be in co-therapy with vigabatrin, and to remit after drug reduction. We observed that psychopathology was related to seizure control in a subgroup of patients. The role of forced normalization, interlinked with interactions with other antiepileptic drugs, could be relevant.