Antiepileptic drugs and liver disease

Systematic review of the pharmacological treatment of alcohol use disorders in individuals infected with hepatitis C

Treating alcohol use disorders (AUD) is critical in individuals suffering from hepatitis C infection (HCV). Aside from psychosocial interventions, pharmacological treatment is effective for decreasing alcohol consumption and promoting abstinence. However, unique factors belonging to HCV-infected individuals, such as baseline hepatic vulnerability and possible ongoing hepatitis C treatment, complicate AUD drug therapy. The goal of this review is to systematically identify, summarize, and evaluate the existing evidence on the pharmacological management of AUD in HCV-infected individuals. MEDLINE, Embase, PsycINFO, and the Cochrane Central Register of Controlled Trials were searched for English- and French-language articles published from 1993 to December 2013. The search criteria focused on clinical trials and observational studies assessing the efficacy and/or safety of pharmacological management of AUD in patients infected with HCV. Of 421 identified studies, three were included for analysis. Two were observational studies assessing the safety of disulfiram. One was a randomized controlled trial assessing the efficacy and safety of baclofen. There is paucity of data regarding the efficacy and safety of pharmacological treatment of AUD in HCV-infected individuals, with studies being small series and showing significant heterogeneity. No strong recommendations can be made based on the current studies as to which pharmacological option should be preferred in this sub-population.

The Spanish Society of Neurology's official clinical practice guidelines for epilepsy. Special considerations in epilepsy: comorbidities, women of childbearing age, and elderly patients

INTRODUCTION

The characteristics of some population groups (patients with comorbidities, women of childbearing age, the elderly) may limit epilepsy management. Antiepileptic treatment in these patients may require adjustments.

DEVELOPMENT

We searched articles in Pubmed, clinical practice guidelines for epilepsy, and recommendations by the most relevant medical societies regarding epilepsy in special situations (patients with comorbidities, women of childbearing age, the elderly). Evidence and recommendations are classified according to the prognostic criteria of Oxford Centre of Evidence-Based Medicine (2001) and the European Federation of Neurological Societies (2004) for therapeutic interventions.

CONCLUSIONS

Epilepsy treatment in special cases of comorbidities must be selected properly to improve efficacy with the fewest side effects. Adjusting antiepileptic medication and/or hormone therapy is necessary for proper seizure management in catamenial epilepsy. Exposure to antiepileptic drugs (AED) during pregnancy increases the risk of birth defects and may affect fetal growth and/or cognitive development. Postpartum breastfeeding is recommended, with monitoring for adverse effects if sedative AEDs are used. Finally, the elderly are prone to epilepsy, and diagnostic and treatment characteristics in this group differ from those of other age groups. Although therapeutic limitations may be more frequent in older patients due to comorbidities, they usually respond better to lower doses of AEDs than do other age groups.

Lacosamide as add-on treatment of focal symptomatic epilepsy in a patient with alcoholic liver cirrhosis

The occurrence of epileptic seizures in the presence of hepatic disease is not uncommon in clinical practice. Selecting an appropriate AED for patients affected by liver failure who have new-onset epileptic seizures can be challenging. We describe a 64-year-old man affected by liver cirrhosis. The patient developed partial epilepsy with secondary generalization because of an intracerebral hemorrhage in the left parieto-occipital regions. After the neurosurgery procedure, seizures reappeared and were initially managed with levetiracetam. After one month, the patient experienced clusters of seizures while on stable treatment with levetiracetam. Pregabalin as add-on was not tolerated; therefore, he received a low dose of phenobarbital as add-on treatment. The patient developed hepatic encephalopathy. Phenobarbital was immediately stopped, and oral lacosamide was added. A rapid recovery of encephalopathy with a 6-month seizure freedom was obtained. The patient died 6 months later because of progressive impairment of liver function. Lacosamide may represent an alternative to other AEDs in patients with liver failure; however, further prospective evaluation of its efficacy and safety in this clinical setting is needed.

Use of antiepileptic drugs in hepatic and renal disease

The use of antiepileptic drugs in patients with renal or hepatic disease is common in clinical practice. Since the liver and kidney are the main organs involved in the elimination of most drugs, their dysfunction can have important effects on the disposition of antiepileptic drugs. Renal or hepatic disease can prolong the elimination of the parent drug or an active metabolite leading to accumulation and clinical toxicity. It can also affect the protein binding, distribution, and metabolism of a drug. The protein binding of anionic acidic drugs, such as phenytoin and valproate, can be reduced significantly by renal failure, causing difficulties in the interpretation of total serum concentrations commonly used in clinical practice. Dialysis can further modify the pharmacokinetic parameters or result in significant removal of the antiepileptic drugs. Antiepileptic drugs that are eliminated unchanged by the kidneys or undergo minimal metabolism include gabapentin, pregabalin, vigabatrin, and topiramate when used as monotherapy. Drugs eliminated predominantly by biotransformation include phenytoin, valproate, carbamazepine, tiagabine, and rufinamide. Drugs eliminated by a combination of renal excretion and biotransformation include levetiracetam, lacosamide, zonisamide, primidone, phenobarbital, ezogabine/retigabine, oxcarbazepine, eslicarbazepine, ethosuximide, and felbamate. Drugs in the latter group can be used cautiously in patients with either renal or liver failure. Antiepileptic drugs that are at high risk of being extracted by hemodialysis include ethosuximide, gabapentin, lacosamide, levetiracetam, pregabalin and topiramate. The use of antiepileptic drugs in the presence of hepatic or renal disease is complex and requires great familiarity with the pharmacokinetics of these agents. Closer follow-up of the patients and more frequent monitoring of serum concentrations are required to optimize clinical outcomes.

Mechanisms of trazodone-induced cytotoxicity and the protective effects of melatonin and/or taurine toward freshly isolated rat hepatocytes

It has been reported that the bioactive intermediate metabolites of trazodone might cause hepatotoxicity. This study was designed to investigate the exact mechanism of hepatocellular injury induced by trazodone as well as the protective effects of taurine and/or melatonin against this toxicity. Freshly isolated rat hepatocytes were used. Trazodone was cytotoxic and caused cell death with LC50 of 300 µm within 2 h. Trazodone caused an increase in reactive oxygen species (ROS) formation, malondialdehyde accumulation, depletion of intracellular reduced glutathione (GSH), rise of oxidized glutathione disulfide (GSSG), and a decrease in mitochondrial membrane potential, which confirms the role of oxidative stress in trazodone-induced cytotoxicity. Preincubation of hepatocytes with taurine prevented ROS formation, lipid peroxidation, depletion of intracellular reduced GSH, and increase of oxidized GSSG. Taurine could also protect mitochondria against trazodone-induced toxicity. Administration of melatonin reduced the toxic effects of trazodone in isolated rat hepatocytes.

Management of chronic pain in elderly, frail patients: finding a suitable, personalized method of control

The elderly population is projected to make up 20% of the total United States population by the year 2030. In addition, epidemiological data suggests increasing prevalence of chronic pain and frailty with advancing age. Pain, being a subjective symptom, is challenging to manage effectively. This is more so in elderly populations with age-specific physiological changes that affect drug action and metabolism. Elderly patients are also more likely to have multiple chronic health pathologies, declining function, and frailty. The barriers present for patients, providers, and health systems also negatively impact efficient and effective pain control. These factors result in disproportionate utilization of health resources by the older population group. The scientific literature is lagging behind in age-specific studies for the elderly population. As a result, there is a lack of age-specific standardized management guidelines for various health problems, including chronic pain. Increasing efforts are now being directed to studies on pain control in the elderly. However, pain management remains inconsistent and suboptimal. This article is an attempt to suggest an informed, comprehensive guide to achieve effective pain control in the presence of these limitations.

Metabolic activation and inflammation reactions involved in carbamazepine-induced liver injury

Drug-induced liver injury is a major safety concern in drug development and clinical pharmacotherapy; however, advances in the understanding of the mechanisms of drug-induced liver injury are hampered by the lack of animal models. Carbamazepine (CBZ) is a widely used antiepileptic agent. Although the drug is generally well tolerated, only a small number of patients prescribed CBZ develop severe hepatitis. In the present study, we developed a mouse model of CBZ-induced liver injury and elucidated the mechanisms accounting for the hepatotoxicity of CBZ. Male BALB/c mice were orally administered CBZ for 5 days. The plasma levels of alanine aminotransferase and aspartate aminotransferase were prominently increased, and severe liver damage was observed via histological evaluation. The analysis of the plasma concentration of CBZ and its metabolites demonstrated that 3-hydroxy CBZ may be relevant in CBZ-induced liver injury. The hepatic glutathione levels were significantly decreased, and oxidative stress markers were significantly altered. Mechanistic investigations found that hepatic mRNA levels of toll-like receptor 4, receptor for advanced glycation end products, and their ligands were significantly increased. Moreover, the plasma concentrations of proinflammatory cytokines were also increased. Prostaglandin E(1) administration ameliorated the hepatic injury caused by CBZ. In conclusion, metabolic activation followed by the stimulation of immune responses was demonstrated to be involved in CBZ-induced liver injury in mice.

Valproate activates ERK signaling pathway in primary human hepatocytes

AIM

Valproic acid (VPA) is a widely-used anticonvulsant and mood-stabilizing agent. VPA is also known to inhibit histone deacetylases (HDACs) affecting the expression of numerous genes.

METHODS

In the present study, we examined the effect of VPA on the extracellular signal-related kinase (ERK, p42/p44) pathway (Ras-Raf-MEK-ERK) belonging to the mitogen-activated protein kinases (MAPKs) pathways in primary human hepatocytes. In the liver, the pathway is associated with progression of hepatocellular carcinoma.

RESULTS

We found that VPA in a therapeutically relevant concentration (500 µM) activates the ERK pathway, as indicated by increased ERK Thr202/Tyr204 phosphorylation. Interestingly, a prototype HDAC inhibitor, trichostatin A, also activated ERK phosphorylation in primary human hepatocytes. These data suggest that HDAC inhibition might be the primary stimulus for ERK pathway activation in primary human hepatocytes. Notably, U0126, a MEK1 inhibitor, was ineffective in inhibiting ERK pathway activation, likely due to its metabolic deactivation in metabolically competent primary human hepatocytes.

CONCLUSION

We conclude that VPA activates the ERK pathway in primary human hepatocytes.

Pharmacological and biochemical analysis of interactions between N-acetylcysteine and some antiepileptic drugs on experimental seizures in mice

PURPOSE

In view of a putative role of oxidative stress in the pathophysiology of seizures, this study addressed the interactions between N-acetylcysteine (NAC), a potent antioxidant and two antiepileptic drugs sodium valproate (SVP) and phenytoin (PHT) on experimental seizures in mice.

METHODS

The interaction was studied at three fixed ratio combinations (i.e., 1:1, 1:3, and 3:1) in the mouse maximal electroshock (MES) test using isobolographic analysis. Markers of oxidative stress (reduced glutathione [GSH] and malondialdehyde [MDA]) were estimated in the cortex of mice pretreated with either of these drugs alone or their 3:1 ratio combinations at the experimentally determined ED(50) values (ED(50 exp) values). The grip strength and spontaneous alternation behavior (SAB) were also assessed. In addition, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and calcium levels were estimated.

RESULTS

We found an anticonvulsant action of NAC in the MES test. Further, the ED(50 exp) values for the combinations of PHT and NAC did not differ from the theoretically calculated ED(50) values indicating additive effects. In case of SVP and NAC, however, the ED(50 exp) values were lower than the theoretically calculated ED(50) values. The interaction of SVP with NAC at the fixed ratios of 1:3 and 3:1 was found to be synergistic. No significant changes were observed in the grip strength, SAB, cortical GSH and MDA levels, serum AST, ALT, ALP, or calcium levels.

CONCLUSION

Our results thus hold promise for the use of NAC as an adjunct to PHT and SVP therapy.

Characteristics of idiosyncratic drug-induced liver injury in children: results from the DILIN prospective study

BACKGROUND

The spectrum and severity of idiosyncratic drug-induced liver injury (DILI) in children are not well established.

PATIENTS AND METHODS

The DILIN (Drug-Induced Liver Injury Network) Prospective Study is a longitudinal multicenter study designed to determine the etiologies, risk factors, and outcomes of suspected DILI. Between September 2004 and September 2009, 30 children ages 2 to 18 years with suspected DILI who met eligibility criteria were enrolled and studied for at least 6 months.

RESULTS

Mean age was 14 years; 70% were girls. Antimicrobial (50%) and central nervous system agents (40%) were the most commonly implicated drug classes, with minocycline (4), isoniazid (3), azithromycin (3), atomoxetine (3), and lamotrigine (3) the leading agents. Median time from drug initiation to symptom onset was 32 days. Peak (median) liver chemistries were aspartate aminotransferase 503  U/L, alanine aminotransferase 727  U/L, alkaline phosphatase 331  U/L, and total bilirubin 3.9  mg/dL. Autoantibodies were common (64%). Liver injury pattern was hepatocellular 78%, cholestatic 13%, and mixed 9%. The DILI episode was scored: mild 32%, moderate 44%, severe 20%, and fatal (within 6 months) 4%. Causality assessment was definite 36%, very likely 36%, probable 16%, possible 8%, and unlikely 4%. Seven percent had persistent liver test abnormalities at 6-month follow-up suggesting chronic DILI. Liver biopsies from 12 children most frequently demonstrated chronic hepatitis or bile duct injury.

CONCLUSIONS

Idiosyncratic DILI in children is most commonly caused by antimicrobial or central nervous system agents and usually presents with a hepatocellular injury pattern. The majority of patients recover, but morbidity and infrequent mortality are seen.

Treatment initiation in epilepsy: an expert consensus in Spain

OBJECTIVE

The goals of this study were to explore the diverse criteria surrounding indications for antiepileptic therapy and to establish a consensus on drug selection for initial monotherapy in adult patients with epilepsy.

METHODS

The study was performed using the modified Delphi method, which aims to achieve professional consensus by means of a series of questionnaires. Three different groups of items were evaluated: the beginning of antiepileptic treatment, the drug selected for initial monotherapy with respect to the type of epilepsy, and the drug selected for initial monotherapy with respect to comorbidity.

RESULTS

Sixty experts completed two rounds of a questionnaire. In the first round, consensus was reached on 135 of the 194 questions analyzed. After the second round, consensus was reached on 148 items. The main findings of the survey revealed a consensus on beginning treatment after the first seizure when the EEG showed abnormalities such as generalized spike-wave discharges, when MRI demonstrated an epileptogenic brain lesion, and in elderly patients. Regarding to the antiepileptic drug selected for initial monotherapy with respect to type of epilepsy, levetiracetam and lamotrigine were recommended for generalized tonic-clonic seizures regardless of sex or age; levetiracetam was recommended for myoclonic epilepsy regardless of sex; valproic acid, ethosuximide, levetiracetam, and lamotrigine were chosen for absence epilepsy; and carbamazepine, levetiracetam, lamotrigine, and oxcarbazepine were recommended for partial epilepsy regardless of age or sex. Finally, in the evaluation of drug selection with respect to comorbidity, first-generation drugs were less recommended than second-generation drugs, which were clearly preferable. The drugs on which there was a greater consensus were levetiracetam, lamotrigine, valproic acid, and topiramate.

CONCLUSIONS

There is a tendency to begin treatment after the first seizure, depending on the results of additional testing. In general, first-generation drugs are less recommended for different types of epilepsy, especially in the presence of a comorbid condition. However, the authors are conveying perceptions and opinions, the effect of which on treatment outcomes has not been evaluated.

Difficulties in Treatment and Management of Epilepsy and Challenges in New Drug Development

Epilepsy is a serious neurological disorder that affects around 50 million people worldwide. Almost 30% of epileptic patients suffer from pharmacoresistance, which is associated with social isolation, dependent behaviour, low marriage rates, unemployment, psychological issues and reduced quality of life. Currently available antiepileptic drugs have a limited efficacy, and their negative properties limit their use and cause difficulties in patient management. Antiepileptic drugs can provide only symptomatic relief as these drugs suppress seizures but do not have ability to cure epileptogenesis. The long term use of antiepileptic drugs is limited due to their adverse effects, withdrawal symptoms, deleterious interactions with other drugs and economic burden, especially in developing countries. Furthermore, some of the available antiepileptic drugs may even potentiate certain type of seizures. Several in vivo and in vitro animal models have been proposed and many new antiepileptic drugs have been marketed recently, but large numbers of patients are still pharmacoresistant. This review will highlight the difficulties in treatment and management of epilepsy and the limitations of available antiepileptic drugs and animal seizure models.

Hepatotoxicity associated with antiepileptic drugs

BACKGROUND

Drug-induced liver injury associated with antiepileptic drugs (AED) is well recognized. The frequency of the most common AED is rare but the consequences can be very serious leading to death or liver transplantation due to acute liver failure induced by these drugs.

CLINICAL FEATURES

Hypersensitivity features are found in more than 70% of patients with phenytoin-induced liver injury, whereas this is only observed in 30% of carbamazepine-associated hepatotoxicity and very rarely with valproate (VPA)-induced liver injury.

PATHOPHYSIOLOGY

The underlying mechanisms behind hepatotoxicity induced by AED are not clear. Reactive metabolites from AED can, in some cases, lead to direct cytotoxicity and liver cell necrosis, whereas in other cases this may lead to neoantigen formation inducing immunoallergic mechanisms.

TREATMENT

No specific therapy is of proved value in severe hepatotoxicity due to AED. However, N-acetylcystein is an appropriate treatment in patients with clinically significant liver injury due to phenytoin and carbamazepine. In patients with VPA-associated liver injury, carnitine that is an important co-factor in the mitochondrial beta-oxidation of fatty acids is the recommended treatment. Early referral of patients with severe liver reactions and coagulopathy to liver transplant centers before encephalopathy can be the difference between liver transplantation and death.

Levetiracetam in patients with epilepsy and chronic liver disease: observations in a case series

OBJECTIVES

To evaluate levetiracetam (LEV) tolerability in patients with epilepsy and liver disease.

METHODS

Fourteen patients with epilepsy and concomitant liver disease were treated with LEV in an open prospective investigation mimicking the daily clinical practice. All patients were stabilized (ie, for at least 1 year) on traditional antiepileptic drugs with complete or partial control of seizures. In the 6-month pre-LEV baseline period, seizure frequency ranged from 3 to 300. Levetiracetam was added on to the basal treatment at a starting daily dose of 250 mg, and the dose was adjusted according to the tolerability and the therapeutic response. Four patients discontinued the drug within the first 3 months because of intolerable side effects. The remaining 10 continued LEV treatment, and the present follow-up is 12 to 38 months.

RESULTS

In the last 6 months of observation, none of the patients showed worsening of liver function on the basis of blood chemistry, and in 4 patients, a complete normalization or a trend toward physiological values of transaminase and/or gamma-glutamyltransferase activity was observed. A greater than 50% reduction in seizure frequency occurred in all uncontrolled patients, 2 of whom achieved seizure freedom during LEV treatment.

CONCLUSIONS

Based on these observations, LEV seems to be an attractive therapeutic option in epileptic patients with chronic liver diseases.

Aromatic antiepileptic drugs and mitochondrial toxicity: effects on mitochondria isolated from rat liver

Idiosyncratic hepatotoxicity is a well-known complication associated with aromatic antiepileptic drugs (AAED), and it has been suggested to occur due to the accumulation of toxic arene oxide metabolites. Although there is clear evidence of the participation of an immune process, a direct toxic effect involving mitochondria dysfunction is also possible. The effects of AAED on mitochondrial function have not been studied yet. Therefore, we investigated, in vitro, the cytotoxic mechanism of carbamazepine (CB), phenytoin (PT) and phenobarbital (PB), unaltered and bioactivated, in the hepatic mitochondrial function. The murine hepatic microsomal system was used to produce the anticonvulsant metabolites. All the bioactivated drugs (CB-B, PB-B, PT-B) affected mitochondrial function causing decrease in state three respiration, RCR, ATP synthesis and membrane potential, increase in state four respiration as well as impairment of Ca2+ uptake/release and inhibition of calcium-induced swelling. As an unaltered drug, only PB, was able to affect mitochondrial respiration (except state four respiration) ATP synthesis and membrane potential; however, Ca2+ uptake/release as well as swelling induction were not affected. The potential to induce mitochondrial dysfunction was PT-B>PB-B>CB-B>PB. Results suggest the involvement of mitochondrial toxicity in the pathogenesis of AAED-induced hepatotoxicity.

Experimental study of hepatoprotective activity of hydroxymethyluracil

Hepatoprotective activity of pyrimidine derivative hydroxymethyluracil was studied on the model of acute paracetamol-induced liver damage in rats. Hydroxymethyluracil was shown to produce a strong hepatoprotective effect.

Glutathione S-transferase M1 null genotype as a risk factor for carbamazepine-induced mild hepatotoxicity

The aim of this study is to verify whether the combination of glutathione S-transferase (GST) M1 null and GSTT1 null genotypes, which is a candidate genetic risk factor for troglitazone-induced liver failure, is common to that for the carbamazepine-induced mild hepatotoxicity. Patients & methods: The genotypes of GSTM1 and GSTT1, and microsomal epoxide hydrolase-3 and -4, were determined in 192 Japanese epileptics treated with carbamazepine. Results: The GSTM1 null (GSTM1-) and GSTT1 null (GSTT1-) genotypes in the subjects were 55.7 and 39.6%, respectively. The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were elevated in 46 (24.0%) and 62 (32.3%) cases, and the mean values were approximately 2.3- and 1.8-times higher than the upper limit of normal levels, respectively. The levels of ALT and AST were significantly higher in GSTM1- than in GSTM1 present (GSTM1+) genotypes (p = 0.007 and 0.004, respectively). The level of ALT was significantly higher in GSTM1-/T1- than in GSTM1+/T1- and GSTM1+/T1+ (p = 0.01 and 0.01, respectively), and that of AST was significantly higher in GSTM1-/T1- and GSTM1-/T1+ than in GSTM1+/T1+ (p = 0.02 and 0.003, respectively). The microsomal epoxide hydrolase genotype did not influence the hepatotoxicity. Conclusion: These findings suggested that GSTM1- rather than GSTM1-/T1- was a risk factor for carbamazepine-induced mild hepatotoxicity.

Use and safety profile of antiepileptic drugs in Italy

OBJECTIVE

To analyse and discuss the use and the safety profile of individual antiepileptic drugs (AEDs) in Italy.

METHODS

The AED safety data referred to the period January 1988-June 2005 and were obtained from the database of the Italian Interregional Group of Pharmacovigilance (GIF). This database collects all spontaneous reports of suspected adverse drug reactions (ADRs) from six Italian regions which are the main contributors to the Italian spontaneous reporting system. Individual AED consumption data (defined daily dose/1,000 inhabitants per day) in the GIF area and in the whole of Italy referred to the period January 2003-June 2005 and were derived from drug sales data (Institute for Medical Statistics Health).

RESULTS

Phenobarbital was the most frequently used AED in the GIF area (4.26 DDD/1,000 inhabitants per day) followed by carbamazepine (1.97), valproic acid (1.33) and gabapentin (1.10). AED consumption in the whole of Italy showed a similar pattern. Gabapentin was the most frequently used AED among newer AEDs. In the GIF database 37,906 reports (up to June 2005) were present; 666 of them (1.76%) were associated with at least one AED (Anatomical Therapeutic Chemical code N03A). The AED with the highest number of reports was carbamazepine (208 reports) followed by phenobarbital (98), gabapentin (80), phenytoin (56), valproic acid (55), lamotrigine (51), oxcarbazepine (43) and vigabatrin (35). Use and toxicity profile were evaluated only for AEDs associated with at least 30 reports. Skin reactions were the most frequently reported ADRs, followed by haematological, general condition, hepatic, neurological and gastrointestinal adverse reactions. Phenobarbital, lamotrigine, carbamazepine and phenytoin had the highest percentage of skin reactions (69, 67, 60 and 54%, respectively). Many haematological reactions were reported for each AED; the highest percentage was related to valproic acid (25%). Vigabatrin was associated with the highest percentage of reactions related to hearing, vision and other senses (97%). Phenytoin and valproic acid had the highest percentage of hepatic reactions (30 and 20%), whereas gabapentin of nervous system, psychiatric, gastrointestinal and urinary reactions (26, 21, 21 and 14%, respectively) and phenobarbital of musculoskeletal reactions (13%).

CONCLUSIONS

In Italy antiepileptic drug therapy appears to be still dominated by traditional drugs. Our analysis showed a different safety profile related to each AED. Some of the drug-adverse reaction associations discussed are not included in the Italian drug leaflets or have not been reported before in the literature.