Uses of topiramate in the treatment of alcohol dependence

Topiramate in Alcohol Use Disorders: Review and Update

To date, a limited number of pharmacological agents exist to treat alcohol use disorders (AUDs), and there is growing interest in new therapeutic tools. In this framework, topiramate may represent a useful treatment option, although its use is not yet approved for AUDs. The main focus of this review is to discuss all the existing data supporting the use of topiramate in AUDs, with an emphasis on the most recent and relevant clinical implications. In addition, the profile of the alcoholic patient who may benefit more from the use of topiramate is outlined. In this regard, the authors conducted a PubMed search of clinical human studies published in English using the following key words: topiramate alcohol dependence, topiramate alcohol withdrawal and topiramate alcoholism. The evidence suggests that topiramate could be an effective treatment option for the management of AUDs, while there are limited results for its use to treat alcohol withdrawal syndrome. In particular, topiramate shows a greater beneficial effect in subjects with a typology of craving characterised by drinking obsessions and automaticity of drinking. Topiramate, within the dosage range of 75-300 mg/day, could be considered as a first-line treatment option for the management of AUDs. Its use appears to be safe and well-tolerated, especially in light of very recent findings.

Effects of topiramate on ethanol-cocaine interactions and DNA methyltransferase gene expression in the rat prefrontal cortex

BACKGROUND AND PURPOSE

Recent and ongoing clinical studies have indicated that topiramate (Topamax®) could be effective in treating ethanol or cocaine abuse. However, the effects of topiramate on the co-administration of ethanol and cocaine remain largely unknown.

EXPERIMENTAL APPROACH

We studied the effects of topiramate, in Wistar rats, on operant ethanol self-administration with the co-administration of cocaine (i.p.). The psychomotor effects of topiramate were examined before ethanol self-administration and cocaine exposure. Blood samples were collected to analyse ethanol and cocaine metabolism (blood ethanol levels and benzoylecgonine). Quantitative real-time PCR was used to characterize the gene expression in the prefrontal cortex.

KEY RESULTS

Topiramate prevented the cocaine-induced increased response to ethanol in a dose-dependent manner without causing any motor impairment by itself. This effect was observed when topiramate was administered before ethanol access, but not when topiramate was administered before the cocaine injection. Topiramate did not block cocaine-induced psychomotor stimulation. Topiramate reduced blood ethanol levels but did not affect cocaine metabolism. Ethanol increased the gene expression of DNA methyltransferases (Dnmt1 and Dnmt3a), the corepressor Dnmt1-associated protein 1 (Dmap1), and the RNA methyltransferase Trdmt1. These effects were prevented by topiramate or cocaine. Gene expression of histone deacetylase-2 and glutamate receptor kainate-1 were only increased by cocaine treatment. Topiramate and cocaine co-administration caused an up-regulation of dopamine (Drd1, Th) and opioid (Oprm1) receptor genes. Topiramate showed a tendency to alter episodic-like memory.

CONCLUSIONS AND IMPLICATIONS

Topiramate is an effective inhibitor of the cocaine-induced increase in operant ethanol self-administration.

Low-dose topiramate in alcohol dependence: a single-blind, placebo-controlled study

INTRODUCTION

Topiramate (TOP) and anticonvulsants in general are considered safe and effective drugs for the treatment of alcohol dependence, even though TOP-induced adverse events are quite common, especially for high initial doses or if titration to 300 mg/d is too rapid. The aim of the present study was to assess the efficacy and tolerability profile of low-dose TOP for relapse prevention.

METHODS

After detoxification, 52 patients were randomized into 2 groups as follows: 26 patients received 100 mg of TOP (oral, twice daily), titrated over 2 weeks, and 26 patients received placebo (PLA). Both groups underwent rehabilitation twice a week.

RESULTS

After 6 weeks of treatment, compared with the PLA group, patients receiving TOP showed the following: (1) fewer drinking days (P < 0.05); (2) less daily alcohol consumption (P < 0.05); (3) more days of treatment (P < 0.05); (4) reduced levels of craving (Obsessive-Compulsive Drinking Scale) and withdrawal symptoms (Clinical Institute Withdrawal Assessment for Alcohol-Revised); and (5) improvement of anxiety, depression, and obsessive-compulsive symptom severity (Symptom Check List 90 Revised).

CONCLUSIONS

Despite the small sample size and the short follow-up period, the present PLA-controlled study demonstrated the potential usefulness of TOP, even when administered at a dosage of 100 mg/d, for the treatment of detoxified alcohol-dependent subjects, confirming results from previous studies testing higher doses of TOP.

Severity of drinking as a predictor of efficacy of the combination of ondansetron and topiramate in rat models of ethanol consumption and relapse

RATIONALE

Alcohol dependence is the third leading cause of preventable death in the USA. While single-agent pharmacotherapies have variable efficacy, medication combinations may produce additive effects by modulating multiple neural pathways.

OBJECTIVES

Here, we examined in animal models of ethanol consumption and relapse the combined effects of ondansetron (a serotonin-3 antagonist) and topiramate (a GABA/glutamate modulator), two medications with demonstrated efficacy for treating alcohol dependence, hypothesizing that their combination would produce a more efficacious response.

METHODS

The effects of acutely administered ondansetron (0-0.01 mg/kg) and topiramate (0-10 mg/kg) alone and in combination on ethanol consumption were examined in alcohol preferring (P) rats (N = 20) and in rats from their background strain (Wistars, N = 20) using a 24-h access free-choice paradigm. Next, we examined their ability to prevent an increase in ethanol consumption following a deprivation period (i.e., an animal model of relapse).

RESULTS

Whether administered alone or combined with ondansetron, topiramate produced a similar modest but persistent reduction in ethanol consumption. However, an analysis of efficacy by drinking level revealed that the combination was superior to topiramate alone in heavy-drinking P rats, but was without effect in lighter-drinking P rats and Wistar rats. Both topiramate alone and the combination blocked the alcohol deprivation effect in both Wistar and P rats with the combination tending to produce a greater decrease than topiramate alone.

CONCLUSIONS

The combination of ondansetron and topiramate may be a promising treatment for preventing relapse and for treating alcohol dependence in heavy-, but not lighter-drinkers.

Molecular targets of alcohol action: Translational research for pharmacotherapy development and screening

Alcohol abuse and dependence are multifaceted disorders with neurobiological, psychological, and environmental components. Research on other complex neuropsychiatric diseases suggests that genetically influenced intermediate characteristics affect the risk for heavy alcohol consumption and its consequences. Diverse therapeutic interventions can be developed through identification of reliable biomarkers for this disorder and new pharmacological targets for its treatment. Advances in the fields of genomics and proteomics offer a number of possible targets for the development of new therapeutic approaches. This brain-focused review highlights studies identifying neurobiological systems associated with these targets and possible pharmacotherapies, summarizing evidence from clinically relevant animal and human studies, as well as sketching improvements and challenges facing the fields of proteomics and genomics. Concluding thoughts on using results from these profiling technologies for medication development are also presented.

[Referral to internal medicine for alcoholism: influence on follow-up care]

BACKGROUND AND AIMS

The problem of high rates of patient drop-out in alcohol treatment programs is frequently reported in the literature. Our aim was to investigate if internal medicine referral could improve abstinence and retention rates in a cohort of alcoholic patients.

PATIENTS AND METHODS

A retrospective observational study was conducted comparing 200 alcoholic patients attending a psychiatric unit (group 1) with 100 patients attending both this unit and an internal medicine unit (group 2). We collected sociodemographic and clinical variables and analysed differences regarding abstinence and retention rates by means of univariate and multivariate analysis.

RESULTS

At 3 and 12 months follow-up, group 2 patients had higher retention and abstinence rates than group 1 patients. Multivariate analysis including potential confounding variables showed that independent predictors of one-year retention were internal medicine referral and being married. Independent predictors of one-year abstinence were being married, age > 44 years and receipt of drug treatment.

CONCLUSIONS

The higher retention rate found among patients referred to Internal Medicine specialists, a result that has not been previously reported to the best of our knowledge, emphasizes the importance of a multidisciplinary team approach in the treatment of alcoholism.

Topiramate does not alter nicotine or cocaine discrimination in rats

The effects of topiramate, a potential treatment for drug dependence, were evaluated in two groups of rats trained to discriminate the administration of either 0.4 mg/kg nicotine or 10 mg/kg cocaine from that of saline, under a fixed-ratio 10 schedule of food delivery. Topiramate (1-60 mg/kg, intraperitoneal) did not produce any nicotine-like or cocaine-like discriminative effects by itself and did not produce any shift in the dose-response curves for nicotine or cocaine discrimination. Thus, the ability to discriminate the effects of nicotine or cocaine does not appear to be altered by topiramate administration. Furthermore, topiramate, given either alone or in combination with nicotine or cocaine, did not depress rates of responding. These experiments indicate that topiramate does not enhance or reduce the ability of rats to discriminate the effects of nicotine or cocaine.

Molecular pharmacodynamics, clinical therapeutics, and pharmacokinetics of topiramate

Topiramate (TPM; TOPAMAX) is a broad-spectrum antiepileptic drug (AED) that is approved in many world markets for preventing or reducing the frequency of epileptic seizures (as monotherapy or adjunctive therapy), and for the prophylaxis of migraine. TPM, a sulfamate derivative of the naturally occurring sugar D-fructose, possesses several pharmacodynamic properties that may contribute to its clinically useful attributes, and to its observed adverse effects. The sulfamate moiety is essential, but not sufficient, for its pharmacodynamic properties. In this review, we discuss the known pharmacodynamic and pharmacokinetic properties of TPM, as well as its various clinically beneficial and adverse effects.

Preclinical and clinical pharmacology of alcohol dependence

In recent years, advances in neuroscience led to the development of new medications to treat alcohol dependence and especially to prevent alcohol relapse after detoxification. Whereas the earliest medications against alcohol dependence were fortuitously discovered, recently developed drugs are increasingly based on alcohol's neurobiological mechanisms of action. This review discusses the most recent developments in alcohol pharmacotherapy and emphasizes the neurobiological basis of anti-alcohol medications. There are currently three approved drugs for the treatment of alcohol dependence with quite different mechanisms of action. Disulfiram is an inhibitor of the enzyme aldehyde dehydrogenase and acts as an alcohol-deterrent drug. Naltrexone, an opiate antagonist, reduces alcohol craving and relapse in heavy drinking, probably via a modulation of the mesolimbic dopamine activity. Finally, acamprosate helps maintaining alcohol abstinence, probably through a normalization of the chronic alcohol-induced hyperglutamatergic state. In addition to these approved medications, many other drugs have been suggested for preventing alcohol consumption on the basis of preclinical studies. Some of these drugs remain promising, whereas others have produced disappointing results in preliminary clinical studies. These new drugs in the field of alcohol pharmacotherapy are also discussed, together with their mechanisms of action.

Pharmakologische Rückfallprävention bei Alkohol- und Tabakabhängigkeit

A better understanding of the neurobiological substrates of alcohol and tobacco dependence has been accompanied by the increasing role of pharmacological relapse prevention. In alcohol dependence, substances which are able to block or ameliorate alcohol craving improve the maintenance of abstinence in combination with psychosocial treatment. In particular, the N-methyl-D-aspartate receptor antagonist acamprosate and the opiate receptor antagonist naltrexone have been shown to be effective in numerous trials. Administration starts immediately after detoxification and should last for 12 months. This treatment, however, is not a replacement for the psychosocial treatment of the alcohol dependence. Compared with placebo treatment, approximately twice as many patients remain abstinent under acamprosate 1 year after the end of treatment. The most widely studied and used pharmacotherapy for the treatment of tobacco dependence is nicotine containing medications. Nicotine replacement therapies (patch, gum, tablet, inhaler) have been shown to reduce tobacco craving and enhance abstinence. The only non-nicotine medication that has been approved in Germany is the antidepressant bupropion. Current studies identify particularly suitable subgroups of patients responding to more individualized pharmacological relapse prevention. A specific application of these substances will optimise the outcome for alcohol and tobacco dependent patients.

Metabolism and excretion of the antiepileptic/antimigraine drug, topiramate in animals and humans

The metabolism and excretion of 2,3:4,5-bis-O-(1-methylethylidene)-beta-D-fructopyranose sulfamate (TOPAMAX, topiramate, TPM) have been investigated in animals and humans. Radiolabeled [14C] TPM was orally administered to mice, rats, rabbits, dogs and humans. Plasma, urine and fecal samples were collected and analyzed. TPM and a total of 12 metabolites were isolated and identified in these samples. Metabolites were formed by hydroxylation at the 7- or 8-methyl of an isopropylidene of TPM followed by rearrangement, hydroxylation at the 10-methyl of the other isopropylidene, hydrolysis at the 2,3-O-isopropylidene, hydrolysis at the 4,5-O-isopropylidene, cleavage at the sulfamate group, glucuronide conjugation and sulfate conjugation. A large percentage of unchanged TPM was recovered in animal and human urine. The most dominant metabolite of TPM in mice, male rats, rabbits and dogs appeared to be formed by the hydrolysis of the 2,3-O-isopropylidene group.

Effects of acute topiramate dosing on open field behavior in mice

Although topiramate (TPM) has been used to treat human disease, there are few studies of its effects on the behavior of animal models. Objective. This study aimed to assess the effect of acute TPM administration on the behavior of mice undergoing the open-field test. Method. The animals were divided in two groups: the treatment group (n = 10), which received 10 mg/kg TPM intraperitoneally, and the control group (n = 10), which received saline. 30 minutes after drug administration, the animals were assessed for 5 minutes in the open-field. The following parameters were analyzed: number of squares explored, immobility time, central area permanence time, peripheral apparatus permanence time, rearing frequency and time, grooming frequency and time, rearing frequency during the last minute, number of fecal boli, and estimated speed. Results. The treatment group had a higher number of squares explored (p = 0.02) and greater estimated speed (p = 0.01). Conclusion. The results suggest that acute TPM administration increases the locomotor activity of mice without interfering with learning, anxiety, stress, and exploratory behavior.