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PubMed2001

Effects of acamprosate on ethanol-seeking and self-administration in the rat.

BACKGROUND: Acamprosate (calcium acetyl homotaurinate) has been used clinically to treat relapse in alcoholics. In rats, it has been shown to decrease ethanol, but not water, self-administration after ethanol deprivation. METHODS: To further investigate the effect of acamprosate on reinforced behaviors in rats, the present experiment used: (1) both ethanol and sucrose reinforcer solutions to better assess the distinct effects of acamprosate on ethanol-directed behaviors, and (2) an operant model that procedurally separates the "cost" to begin drinking from consuming the reinforcer solutions to dissociate the effects of acamprosate on appetitive versus consummatory processes. In daily sessions (5 days/week), rats (n = 6/group) were trained to make 30 lever-press responses to gain access for 20 min to a sipper tube containing either ethanol (10%) or sucrose (3%). After stable responding, acamprosate treatment was given. Three doses were tested (50, 100, and 200 mg/kg/injection, intraperitoneally), one dose per week. Each week, a total of four injections were given (21 and 2 hr before the operant sessions over 2 consecutive days). RESULTS: At these doses, acamprosate had no effect on the measures of appetitive responding for either solution. However, all doses reliably decreased ethanol consumption on the 2nd day of treatment (from an average of 0.83 to 0.63 g/kg). Analysis of the pattern of ethanol consumption showed that the effects of acamprosate occurred after the onset of a normal pattern of intake, as measured by lick rate and size of the initial bout of drinking, which suggested that acamprosate is most effective when combined with the pharmacological effects of ethanol. Sucrose intake was unaffected by all acamprosate treatments, which indicated that the treatment effects were specific to ethanol and not due to a general decrease in consummatory behavior. CONCLUSIONS: Overall, these results suggest that acamprosate is effective at reducing total ethanol intake, but may not reliably alter subjects propensity to begin a drinking bout as measured by this model. However, whether this applies to the clinical use of acamprosate, where other types of reinforcement may also precipitate relapse drinking, is not certain.

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PubMed2004

Predictors of acamprosate efficacy: results from a pooled analysis of seven European trials including 1485 alcohol-dependent patients.

RATIONALE: Acamprosate is a proven effective intervention in the treatment of alcohol dependence. However, acamprosate prevents lapses or relapses only in a minority of patients. An important question, therefore, is whether there is a specific subgroup of patients who respond particularly well to acamprosate. OBJECTIVES: To identify predictors of acamprosate efficacy. Based upon the available evidence and hypotheses about the mechanisms underlying acamprosate's effects on drinking behavior, the following variables were considered to be potential positive predictors: high physiological dependence at baseline, negative family history of alcoholism, late age-of-onset, serious anxiety symptomatology at baseline, severe craving at baseline, and female gender. METHOD: Potential predictors of acamprosate's efficacy were analyzed in a pooled analysis of data from seven randomized placebo-controlled trials involving a total of 1485 patients with alcohol dependence. Outcome is measured in terms of cumulative abstinence duration (CAD), continuous abstinence (ABST), and time to first relapse (TFR). RESULTS: CAD and ABST were predicted by baseline measures of craving and anxiety, as well as by study and treatment condition. Acamprosate efficacy was not differentially associated with any of the predictor variables. Importantly, the hypotheses were rejected despite the large sample size and sufficient statistical power. COMMENT: The most straight-forward clinical implication of this study is that acamprosate can be considered as a potentially effective pharmacotherapy for all patients with alcohol dependence. The effect size of acamprosate alone is, however, moderate. Some evidence indicates that the combination of acamprosate with naltrexone or disulfiram leads to substantially better outcomes.

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PubMedDate not supplied

Kinetic study of acamprosate absorption in rat small intestine.

Acamprosate (calcium bis acetyl-homotaurine), a homotaurine derivative, a structural analogue of gamma-aminobutyric acid (GABA) and an upper homologue of taurine, is a relatively new drug used to prevent relapse in weaned alcoholics. When administered orally as enteric-coated tablets at relatively high doses, this drug has a bioavailability of about 11%; however, the intestinal absorption mechanism has not been studied in depth. The present study was therefore planned to characterize the intestinal transport of acamprosate in the rat and the effect of chronic alcohol treatment on this process, quantifying its kinetic parameters and investigating possible inhibitors. Using an in vitro technique, acamprosate absorption was measured in the rat intestine from three different groups: alcohol group [fed a liquid diet containing 5% (w/v) ethanol for 4 weeks], isocaloric pair-fed control, and a solid diet group. Intestinal acamprosate absorption was found to occur mainly by passive diffusion with a diffusive permeability of 0.213+/-0.004 cm/h in control pair-fed animals, 0.206+/-0.001 cm/h in animals receiving chronic alcohol treatment, and 0.193+/-0.001 cm/h in the solid diet group. Inhibition studies showed that at a 10(-3) M acamprosate concentration, some compounds such as GABA, taurine, proline, and glycine at 40 mM each did not affect acamprosate transport. Nevertheless, when a lower concentration of the drug (10(-4) M) was assayed, a significant reduction of acamprosate transport in the presence of taurine or GABA 40 mM was found. These results suggest that acamprosate in the rat jejunum, could be transported, in part, by a carrier system. Further experiments using different concentrations of taurine (10, 20, and 80 mM) showed that the maximum inhibition (32%) is achieved at 20 mM of taurine. These latter results suggest that acamprosate and taurine share, at least, an intestinal carrier system in rat jejunum. From the above results, it can be concluded that there are probably two pathways involved in the intestinal absorption of acamprosate: passive diffusion and mediated transport, with the former being predominant. Moreover, neither chronic ethanol intake nor the type of diet seems to alter the intestinal absorption of the drug.

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PubMedDate not supplied

Acamprosate during and after acute alcohol withdrawal: a double-blind placebo-controlled study in Spain.

To test acamprosate's role as an aid in preventing relapse after detoxification, 296 alcohol-dependent patients entered a prospective, multicentre, randomized, double-blind, parallel comparison of acamprosate treatment consisting of two 333 mg tablets given three times daily for 180 days with matching placebo treatment. Unlike previous studies, acamprosate was prescribed from the start of alcohol withdrawal, rather than after the detoxification process. During the treatment period, 110 patients dropped out. The two treatment groups were balanced with regard to baseline values and reasons for discontinuation. There was no difference between the groups in the severity of withdrawal symptoms as measured by the CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol scale). Acamprosate given during withdrawal did not cause unwanted effects. The cumulative abstinence duration (CAD, main end-point) was 19 days longer in the acamprosate treatment group than the placebo treatment group (analysis of variance on ranks, P = 0.0006) and the stable recovery duration, defined as the number of abstinent days between the last relapse into any drinking and the end of the trial, was 16 days longer in the acamprosate treatment group (P = 0.021). Continuous abstinence, estimated by survival analysis on time to first relapse, was achieved by 35% of acamprosate-treated patients and 26% of placebo-treated patients (log rank P = 0.068). The geometric mean of the ratio final/baseline values for serum carbohydrate-deficient transferrin was 0.802 (placebo) and 0.733 (acamprosate) (P = 0.059). The geometric mean of the ratio final/baseline values for serum gamma-glutamyltransferase was 0.496 (placebo) and 0.415 (acamprosate) (P = 0.024) which corroborated the greater abstinence reported by the acamprosate group.

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PubMed1999

Acamprosate. Pharmacoeconomic implications of therapy.

Acamprosate is thought to reduce the craving for alcohol. The drug helps to maintain abstinence in alcohol-dependent patients who have successfully undergone detoxification. Abstinence rates during 3 to 12 months' treatment with acamprosate were approximately double those with placebo in most clinical trials, although abstinence rates were generally still < 50% in patients assigned to receive acamprosate. The drug is generally well tolerated, with the most common adverse effect being diarrhoea. In a German cost-effectiveness model, a treatment programme including acamprosate was the dominant strategy, producing a lifetime cost saving of 2602 Deutschmarks (1992 to 1995 values) per additional abstinent patient compared with treatment without acamprosate. In a Belgian pharmacoeconomic model, total direct medical costs over 2 years were 21,301 Belgian francs (1997 values) per patient lower with a treatment programme including acamprosate than treatment without acamprosate in alcohol-dependent patients. The main factors in the cost savings with acamprosate in these models were reduced costs for acute hospitalisation and rehabilitation/follow-up. The results of a cost-benefit analysis that considered both direct and indirect costs for the total alcohol-dependent population in Spain were consistently in favour of acamprosate. The lifetime net benefit for acamprosate over placebo (the incremental benefit) ranged between 61,642 million and 99,069 million pesetas (1996 values) in various scenarios with 40 to 60% of patients receiving treatment.

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PubMed2002

Acamprosate has no effect on NMDA-induced toxicity but reduces toxicity induced by spermidine or by changing the medium in organotypic hippocampal slice cultures from rat.

BACKGROUND: It has been suggested that the antirelapse drug acamprosate can inhibit or potentiate glutamate/NMDA receptor-mediated responses via a polyamine site. Additionally, subchronic exposure to acamprosate increases expression of some NMDA receptor subunits. These effects on NMDA receptors imply that the drug may have neurotoxic or neuroprotective actions under different conditions, and these studies were undertaken to evaluate this possibility in hippocampal neuronal cultures. METHODS: Organotypic hippocampal cultures from 8-day-old neonatal rats were maintained in medium for 28 days. The effects of acamprosate (100 microM) alone or on neurotoxic challenges induced by either 50 microM NMDA or 100 microM spermidine were studied. Neurotoxicity was assessed by uptake of propidium iodide 24 hr after challenge. Calcium entry was measured by uptake of 45Ca2+ into the culture during the challenge. RESULTS: Acamprosate produced no neurotoxicity in these cultures after acute or subchronic exposure. In contrast, the presence of acamprosate significantly reduced "basal" propidium iodide uptake caused by the medium change procedure; similar effects were obtained with dizocilpine (MK-801; 30 microM) and, to a lesser extent, with ifenprodil (50 microM). Acamprosate did not significantly potentiate or inhibit NMDA-induced neurotoxicity, but the presence of acamprosate significantly reduced spermidine-induced neurotoxicity. CONCLUSION: No evidence was obtained that the putative agonist or coagonist effects of acamprosate on the NMDA receptor are able to cause neurotoxicity. Similarly, no evidence for inhibitory effects of acamprosate on NMDA-induced toxicity was observed under any of these conditions. However, acamprosate significantly inhibited the toxicity associated with changing medium and the toxicity induced by spermidine in these hippocampal cultures. The mechanism is unknown but is compatible with previously reported inhibition of polyamine-mediated effects.

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PubMed2003

Local acamprosate modulates dopamine release in the rat nucleus accumbens through NMDA receptors: an in vivo microdialysis study.

The effects of acamprosate on the in vivo dopamine extracellular levels in the nucleus accumbens and the involvement of N-methyl-D-aspartate (NMDA) receptors in these effects were investigated. Microdialysis in freely moving rats was used to assess dopamine levels before and during simultaneous perfusion of acamprosate and/or different agonists or antagonists of NMDA receptors. Perfusion with acamprosate at concentrations of 0.5 and 5 mM provoked a concentration-dependent increase in extracellular dopamine in nucleus accumbens. The lowest concentration of acamprosate assayed (0.05 mM) had no effect on dopamine levels. Infusion of NMDA (25 and 500 microM) and the glutamate uptake blocker, L-trans-pyrrolidine-2,4-dicarboxilic acid (PDC) (0.5 mM) into the NAc caused a significant increase in DA, whereas acamprosate (0.05 mM) co-infusion with these compounds blocked or attenuated the NMDA and PDC-induced increases in DA levels. Co-infusion of the selective antagonist of NMDA receptors, DL-2-amino-5-phosphonopentanoic acid (AP5) (400 microM) with acamprosate (0.5 mM), did not reduce the increase of DA levels induced by acamprosate. These results demonstrate that acamprosate is able to modulate DA extracellular levels in NAc via NMDA receptors and suggest that acamprosate acts as an antagonist of NMDA receptors.

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PubMed2002

Acamprosate reduces context-dependent ethanol effects.

RATIONALE: Previous studies have indicated that the conditioned effects of environmental stimuli contribute to ethanol tolerance and abuse. Acamprosate was recently suggested to reduce the effects of environmental stimuli previously associated with ethanol administrations. This action is believed to contribute to the clinical benefits of acamprosate treatment in alcoholics. OBJECTIVES: In the present experiment, a classical drug-conditioning paradigm was used to test whether acamprosate modulates the effects of ethanol-paired environmental stimuli on spontaneous motor activity. METHODS: Wistar rats were divided into three groups: cued, uncued and control. The cued group daily received ethanol injections (2.0 g/kg, IP) in a specific testing environment. The uncued group daily received ethanol injections (2.0 g/kg, IP) in their home cage but never experienced ethanol in the testing environment. The control group was injected with saline and never experienced ethanol. After 8 conditioning days, the rats were IP injected with various ethanol doses (saline, 1.0, 1.5 or 2.0 g/kg) and their spontaneous motor activity in the testing environment was recorded to investigate their respective tolerance to ethanol inhibitory effects. In the second part of the study, the same procedure was repeated with chronically acamprosate-treated rats. The chronic acamprosate treatment (400 mg/kg per day) started 2 weeks before the conditioning procedure by diluting acamprosate in the drinking bottles and was maintained throughout the whole experiment. RESULTS: The cued rats showed a significant environment-dependent tolerance to ethanol inhibitory effects relative to the uncued and control rats. This higher ethanol tolerance of the cued rats was mainly due to a faster recovery from ethanol's inhibitory effects on spontaneous activity. Furthermore, the cued rats showed a higher level of activity in the testing environment after the saline injection. However, it is not clear whether this hyperactivity is a conditioned compensatory response or an increased exploratory behavior. Acamprosate totally abolished the environment-dependent tolerance to ethanol, whereas it did not alter the hyperactivity of the cued rats in the testing environment. CONCLUSIONS: The results of the present study suggest that acamprosate reduces ethanol-conditioned effects. Such an action may be of importance to explain the anti-relapse effects of acamprosate.

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PubMed2002

A pharmacokinetic and pharmacodynamic drug interaction study of acamprosate and naltrexone.

Acamprosate and naltrexone have each demonstrated safety and efficacy for alcohol dependence in placebo-controlled clinical trials. There is scientific and clinical interest in evaluating these drugs in combination, given their high tolerability, moderate effect sizes, different pharmacological profiles and potentially different effects on drinking outcomes. Thus, this is the first human pharmacokinetic and pharmacodynamic drug interaction study of acamprosate and naltrexone. Twenty-four normal, healthy adult volunteers participated in a double-blind, multiple dose, within subjects, randomized, 3-way crossover drug interaction study of the standard therapeutic dose of acamprosate (2 g/d) and the standard therapeutic dose of naltrexone (50 mg/d), given alone and in combination, with seven days per treatment condition and seven days washout between treatments. Blood samples were collected on a standardized schedule for pharmacokinetic analysis of naltrexone, 6-beta-naltrexol, and acamprosate. A computerized assessment system evaluated potential drug effects on cognitive functioning. Coadministration of acamprosate with naltrexone significantly increased the rate and extent of absorption of acamprosate, as indicated by an average 33% increase in acamprosate maximum plasma concentration, 33% reduction in time to maximum plasma concentration, and 25% increase in area under the plasma concentration-time curve. Acamprosate did not affect the pharmacokinetic parameters of naltrexone or 6-beta-naltrexol. A complete absence of negative interactions on measures of safety and cognitive function supports the absence of a contraindication to co-administration of acamprosate and naltrexone in clinical practice.

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PubMed2004

A pragmatic trial of acamprosate in the treatment of alcohol dependence in primary care.

AIMS: To assess the effectiveness of pharmacotherapy with acamprosate in alcohol-dependent patients treated in a naturalistic setting in primary care in France. METHODS: The ARES (Acamprosate et Repercussions Economiques et Sociales; Acamprosate and Economic and Social Repercussions) study was performed by 149 general practitioners interested in treating alcohol use disorders in France who included patients fulfilling DSM-IV criteria for alcohol dependence. The only exclusion criteria concerned contra-indications to acamprosate, co-medication with naltrexone and multiple substance abuse. Eligible patients were randomized to one of two treatment arms, either standard care alone or standard care with acamprosate, using an open-label design and followed up quarterly for a period of 1 year. The primary outcome variable was the change from baseline on the Alcohol-Related Problems Questionnaire. Secondary efficacy variables were abstinence, Clinical Global Impression, quality of life measured with the SF-36 and incidence of adverse events. An intent-to-treat population was used for outcome analysis. RESULTS: 422 patients were included, of whom 348 (82%) completed the protocol as planned. At the end of the study, patients randomized to the acamprosate group had significantly better outcomes in terms of total ARPQ score, change from baseline (-2.61 vs -3.44) and number of subjects with no alcohol-related problem. On average, patients treated with acamprosate had one less alcohol-related problem than did the controls. The number needed to treat in order to save one additional patient from alcohol-related problems compared to standard care was 7.14. Statistically significant differences in favour of the acamprosate group were observed for all secondary efficacy outcome measures including quality of life. CONCLUSIONS: Adjunctive therapy with acamprosate in primary care is associated with significantly better functional outcome. Pragmatic trials in alcohol dependence are both feasible and informative.

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PubMed1998

Combined efficacy of acamprosate and disulfiram in the treatment of alcoholism: a controlled study.

This study presents the results of a multicenter investigation of the efficacy of acamprosate in the treatment of patients with chronic or episodic alcohol dependence. One hundred eighteen patients were randomly assigned to either placebo or acamprosate, and both groups were stratified for concomitant voluntary use of disulfiram. Treatment lasted for 360 days, with an additional 360-day follow-up period. The primary efficacy parameters evaluated were: relapse rate and cumulative abstinence duration (CAD). Results were analyzed according to Intention-To-Treat principles using chi2, t, and multiple regression analyses where appropriate. After 30 days on study medication, 40 of 55 (73%) acamprosate-treated patients were abstinent, compared with 26 of 55 (43%) placebo-treated patients (p = 0.019). The treatment advantage remained throughout the study medication period and was statistically significant until day 270 (p = 0.028). Twenty-seven percent of patients on acamprosate and 53% of patients on placebo had a first drink within the first 30 days of the study. The mean CAD was 137 days (40% abstinent days) for the patients treated with acamprosate and 75 days (21% abstinent days) for the placebo group (p = 0.013). No adverse interaction between acamprosate and disulfiram occurred, and the subgroup who received both medications had a better outcome on CAD than the those on only one or no medication. Acamprosate was well tolerated. Diarrhea was the only significant treatment-induced effect. It was concluded that acamprosate was a useful and safe pharmacotherapy in the long-term treatment of alcoholism. Concomitant administration of disulfiram improved the effectiveness of acamprosate.

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PubMed2005

Rationale for combining acamprosate and naltrexone for treating alcohol dependence.

OBJECTIVE: This article provides an evidence-based review of acamprosate and naltrexone, used alone and in combination. Both medications are gaining increasing availability worldwide by prescription for the treatment of alcohol dependence. There is scientific and clinical interest in examining these drugs in combination, given their high tolerability, moderate effect sizes, different pharmacological profiles and potentially different effects on drinking outcomes. METHOD: This article includes a review of the key similarities and differences between acamprosate and naltrexone in the treatment of alcohol dependence; the published double-blind, placebo-controlled trials of acamprosate and naltrexone across a uniform range of outcome criteria to elucidate the differences and similarities in the behavioral effects of these drugs; the two published pharmacokinetic and pharmacodynamic drug interaction studies of acamprosate and naltrexone; and the single-site clinical trial of acamprosate and naltrexone used alone and in combination relative to placebo. RESULTS: Pharmacokinetic and pharmacodynamic studies report an increase in acamprosate plasma levels with no clinically significant elevation in adverse events when the two drugs are used in combination. Data from dose-response studies for acamprosate alone suggest that the augmentation of acamprosate plasma levels by co-administration of naltrexone may have clinical benefits. CONCLUSIONS: These factors support investigating the efficacy and safety of combining acamprosate and naltrexone for the treatment of alcohol dependence in a large-scale multisite trial, with evaluation of potential predictors of response to each drug alone and in combination relative to placebo.

Acamprosate↗
PubMedDate not supplied

[Acamprosate (Aotal): could adverse effects upset the treatment of alcohol dependence?].

Acamprosate, a stimulant of central inhibitory GABA neurotransmision and an antagonist of excitatory amino acids, is used in alcohol withdrawal and for the maintenance of abstinence. After identification of several cases of treatment discontinuation during alcohol abstinence because of acamprosate-induced adverse drug reactions (ADRs), a retrospective study was conducted in order to investigate and quantify acamprosate-induced ADRs. Up to July 2002, 472 patients were included for treatment of alcohol withdrawal: of these, 68% (n = 322) received acamprosate. At least one ADR occurred in 98 patients (30%). The mean age of the patients was 41.5 +/- 8.8 years (range: 24-65) and 70% were male. All ADRs were classified as 'non serious'. However, ADRs required a dose decrease in 61 cases or acamprosate discontinuation in 76 cases (62.2% and 77.5%, respectively, of patients with an ADR). We identified mainly gastrointestinal ADRs in 67 patients (mean delay before occurrence: 7.6 days), i.e. 20.8% of patients treated with acamprosate (corresponding to 68.3% of ADRs), with a positive rechallenge in five cases. Moreover, cutaneous ADRs (pruritus) occurred in 29 patients (mean delay before occurrence: 9.0 days), and required acamprosate withdrawal in 22 patients (75.9%) with a prior dose decrease in 18 of these patients (62.1%). Our results show that a dose decrease or withdrawal of acamprosate was necessary in 18.9% and 23.6%, respectively, of patients because of the occurrence of ADRs. The present study shows the important role of acamprosate-induced ADRs among the various causes for failure of alcohol abstinence.

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PubMed2002

Disposition of acamprosate in the rat: influence of probenecid.

The purpose of the present study was to investigate the disposition of acamprosate (calcium bis acetyl-homotaurine) in the rat. Initially, we studied the linearity of acamprosate disposition and the fraction of acamprosate excreted unchanged in the urine of the animals. Rats received 9.3, 36.6 or 73.3 mg/kg of the drug as an intravenous bolus. The statistical analysis of the pharmacokinetic parameters did not reveal any significant difference, indicating that acamprosate disposition was linear within the range of the doses assayed. On average, 95% of the administered dose was excreted unchanged in the urine of the animals in the 0-6 h post-administration period indicating that renal excretion is the main elimination route for this drug. Acamprosate was also administered by the intravenous route at three different constant infusion rates (2.65, 132.5 and 530 microg/min) in order to quantify total (Cl(t)) and renal (Cl(r)) plasma clearances at steady-state conditions. The mean Cl(r) values were, respectively, 4.60+/-0.42, 4.28+/-0.52 and 4.08+/-0.67 ml/min, practically equivalent to the Cl(t) values (4.78+/-0.38, 4.51+/-0.36 and 4.21+/-0.56 ml/min), confirming that the drug is mainly eliminated via renal excretion. Moreover, Cl(r) values were clearly higher than the glomerular filtration rate (2.61+/-0.26 ml/min), suggesting the existence of a highly efficient tubular secretion mechanism in the renal excretion of the drug. To confirm this hypothesis, two groups of rats were intravenously treated with probenecid (33.3 or 66.6 mg/kg) prior to acamprosate administration (9.3 mg/kg). Probenecid provoked a statistically significant dose-dependent reduction in the total clearance of acamprosate (from 5.8+/-0.7 ml/min in the control group to 2.6+/-0.1 ml/min in the animals treated with 66 mg/kg of probenecid) demonstrating the existence of a tubular secretion process on the renal excretion of acamprosate in the rat.

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PubMed2001

Acamprosate is neuroprotective against glutamate-induced excitotoxicity when enhanced by ethanol withdrawal in neocortical cultures of fetal rat brain.

BACKGROUND: Acamprosate reduces relapse, and the drug may interact with glutamate transmission and with glutamate/NMDA receptors. Because these systems are implicated in excess calcium entry leading to alcohol withdrawal-induced neurotoxicity, we evaluated the effects of acamprosate on these parameters in neuronal cultures. METHODS: Primary cultures of neocortical neurons from fetal Sprague-Dawley rats were maintained either in normal medium or in medium containing 100 mM ethanol for 4 days. After this time, cultures were challenged with glutamate for 10 min and then returned to medium (all in the absence of ethanol). 45Ca2+ uptake was measured during the challenge, and glutamate-induced toxicity was assessed after 20 hr. The effects of acamprosate present during the glutamate challenge were measured on both parameters. RESULTS: In controls, acamprosate did not significantly affect glutamate-induced neurotoxicity but produced a significant inhibition of calcium entry. The NMDA receptor antagonists dizocilpine and d-amino-phosphonovalerate (D-APV) inhibited both glutamate neurotoxicity and calcium entry. In cultures previously exposed to ethanol, glutamate-induced neurotoxicity and calcium entry were both significantly enhanced. Dizocilpine reduced both these parameters to unstimulated control values, and D-APV reduced both calcium entry and neurotoxicity with the same relation that we obtained in control cultures. In the ethanol-withdrawn cultures, acamprosate reduced both the enhanced glutamate-induced calcium entry and the enhanced neurotoxicity in a concentration-dependent manner. Acamprosate also significantly reduced calcium entry caused by 80 mM K+ in control and ethanol-exposed cultures. CONCLUSIONS: Acamprosate had protective effects against glutamate-induced neurotoxicity only in ethanol-withdrawn cultures. The neuroprotective effects of the drug did not correlate with its effects on calcium entry, making it unlikely that acamprosate directly affects NMDA receptors via the glutamate binding site or the receptor-operated calcium channel. The results are, however, compatible with other inhibitory effects on NMDA receptor function.

Acamprosate↗
PubMed2002

Acamprosate, MK-801, and ifenprodil inhibit neurotoxicity and calcium entry induced by ethanol withdrawal in organotypic slice cultures from neonatal rat hippocampus.

BACKGROUND: The antirelapse drug acamprosate has previously been reported to inhibit activating effects of polyamines on -methyl-D-aspartic acid receptor (NMDAR) function. Because increased synthesis of polyamines has been suggested as a mechanism for potentiation of NMDAR function during ethanol withdrawal, we evaluated the effects of acamprosate, MK-801, and ifenprodil in a cell culture model of ethanol withdrawal-induced neurotoxicity. METHODS: Organotypic hippocampal cultures from 8-day-old neonatal rats were maintained in vitro for 23 days before experimental use. The ethanol withdrawal model consisted of exposing cultures to ethanol (70-100 mM) for 4 days before being "withdrawn" into Calcium-Locke's buffer for 1 hr and then into minimal medium for 23 hr. Uptake of (45)CaCl(2) and propidium iodide by damaged cells was assessed 1 hr and 24 hr after the start of ethanol withdrawal, respectively. Additional studies examined effects of exposure to NMDA (50 microM) or spermidine (100 microM) on withdrawal-induced hippocampal damage. Last, these studies examined the ability of the sodium salt of acamprosate (Na-acamprosate, 200 microM), ifenprodil (50 microM), or MK-801 (30 microM) to inhibit neurotoxicity and (45)Ca(2+) entry produced by these insults. RESULTS: Ethanol withdrawal was associated with significantly greater toxicity and (45)Ca(2+) entry, relative to controls. Exposure to spermidine and NMDA during ethanol withdrawal further increased neurotoxicity and (45)Ca(2+) entry. Acamprosate, ifenprodil, and MK-801 almost completely prevented ethanol withdrawal-induced toxicity and (45)Ca(2+) entry. Acamprosate also reduced spermidine-induced neurotoxicity during ethanol withdrawal but was ineffective against NMDA-induced toxicity or (45)Ca(2+) entry at this time. CONCLUSIONS: The results support the contention that acamprosate, like ifenprodil, interacts with polyamines and that these compounds may be effective in reducing consequences of ethanol withdrawal. NMDAR activation is also strongly implicated in ethanol withdrawal neurotoxicity, but whether acamprosate causes any of these effects in this preparation directly via the NMDAR remains uncertain.

Acamprosate↗
PubMedDate not supplied

[Acamprosate. From pharmacology to therapeutics].

Acamprosate is an homotaurine derivative, structural analogue of Gamma amino butyric acid and upper homologue of taurine. Its crossing through the blood brain barrier is facilitated by acetylation and calcium salification. Acamprosate has a very weak toxicity attributable to the ingested dose of calcium. Acamprosate is a GABAagonist showing pharmacological activity on direct and indirect tests of GABA activity and a high binding capacity with GABA receptors. Acamprosate also shows beta-adrenergic and serotoninergic activity, probably due to its GABAergic activity. Acamprosate is neither and antidepressant, nor a neuroleptic or a tranquillizer. In experimental alcohology, on different animal models (alcohol preferring or alcohol dependent) acamprosate induces a very clear and highly significant reduction of alcohol consumption. This effect is progressive and dose dependent, antagonized by bicuculine which is a GABA agonist. Besides, acamprosate reduces the intensity of the alcohol withdrawal syndrome. Clinical alcohology is a very difficult field for strict methodology in therapeutic trials: determination of inclusion characters, choice of judgment criteria, reduction of the number of drop out and lost subjects, length of evaluation... Different clinical controlled studies, most in double blind against placebo, on patients suffering from signs of physical or psychical alcohol addiction as well as biological modifications due to their ethylic consumption showed beneficial effects of acamprosate (in weaned alcoholics after withdrawal) according to clinical criteria (the number of abstinents after 3 months was doubled: 60% with active drug--30% with placebo) and for biological criteria (Normalization of Gamma Glutamyl Transpeptidase level in blood). The tolerance is good.(ABSTRACT TRUNCATED AT 250 WORDS)

Acamprosate↗
PubMed2003

Comparing and combining naltrexone and acamprosate in relapse prevention of alcoholism: a double-blind, placebo-controlled study.

BACKGROUND: Naltrexone and acamprosate have been shown to be effective in relapse prevention of alcoholism via different pharmacologic mechanisms. Since it remains uncertain whether both substances are equally efficient and whether a combination of both drugs potentiates the efficacy, we conducted the first published controlled study comparing and combining both compounds. METHODS: After detoxification, 160 patients with alcoholism participated in a randomized, double-blind, placebo-controlled protocol. Patients received naltrexone, acamprosate, naltrexone plus acamprosate, or placebo for 12 weeks. Patients were assessed weekly by interview, self-report, questionnaires, and laboratory screening. Time to first drink, time to relapse, and the cumulative abstinence time were the primary outcome measures. RESULTS: Naltrexone, acamprosate, and the combined medication were significantly more effective than placebo. Comparing the course of nonrelapse rates between naltrexone and acamprosate, the naltrexone group showed a tendency for a better outcome regarding time to first drink and time to relapse. The combined medication was most effective with significantly lower relapse rates than placebo and acamprosate but not naltrexone. CONCLUSIONS: The results of this study support the efficacy of pharmacotherapeutic strategies in the relapse prevention of alcoholism. Naltrexone and acamprosate, especially in combination, considerably enhance the potential of relapse prevention.

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