A reverse translational study of PPAR-α agonist efficacy in human and rodent models relevant to alcohol use disorder

Alcohol Use Disorder (AUD) is a chronic relapsing disorder affecting an estimated 283 million individuals worldwide, with substantial health and economic consequences. Peroxisome proliferator-activated receptors (PPARs), particularly PPAR-α and PPAR-γ, have shown promise in preclinical studies as potential therapeutic targets for AUD. In this human laboratory study, we aimed to translate preclinical findings on the PPAR-α agonist fenofibrate to a human population with current AUD. We hypothesized that, relative to placebo, fenofibrate at the highest FDA-approved dose of 145 mg/d would attenuate responsiveness to in vivo alcohol cues in the lab and reduce drinking under natural conditions. However, the results did not show significant differences in craving and alcohol consumption between the fenofibrate and placebo groups. Reverse translational studies in rodent models confirmed the lack of fenofibrate effect at human-equivalent doses. These findings suggest that inadequate translation of drug dose from rodents to humans may account for the lack of fenofibrate effects on alcohol craving and consumption in humans with AUD. The results highlight the need for new brain-penetrant PPAR-α agonists to adequately test the therapeutic potential of PPAR-α agonists for AUD, and the importance of reverse translational approaches and selection of human-equivalent doses in drug development.

Preclinical and clinical evidence for suppression of alcohol intake by apremilast

Treatment options for alcohol use disorders (AUDs) have minimally advanced since 2004, while the annual deaths and economic toll have increased alarmingly. Phosphodiesterase type 4 (PDE4) is associated with alcohol and nicotine dependence. PDE4 inhibitors were identified as a potential AUD treatment using a bioinformatics approach. We prioritized a newer PDE4 inhibitor, apremilast, as ideal for repurposing (i.e., FDA approved for psoriasis, low incidence of adverse events, excellent safety profile) and tested it using multiple animal strains and models, as well as in a human phase IIa study. We found that apremilast reduced binge-like alcohol intake and behavioral measures of alcohol motivation in mouse models of genetic risk for drinking to intoxication. Apremilast also reduced excessive alcohol drinking in models of stress-facilitated drinking and alcohol dependence. Using site-directed drug infusions and electrophysiology, we uncovered that apremilast may act to lessen drinking in mice by increasing neural activity in the nucleus accumbens, a key brain region in the regulation of alcohol intake. Importantly, apremilast (90 mg/d) reduced excessive drinking in non-treatment-seeking individuals with AUD in a double-blind, placebo-controlled study. These results demonstrate that apremilast suppresses excessive alcohol drinking across the spectrum of AUD severity.

Suvorexant, an FDA-approved dual orexin receptor antagonist, reduces oxycodone self-administration and conditioned reinstatement in male and female rats

Background: The Department of Health and Human Services reports that prescription pain reliever (e.g., oxycodone) misuse was initiated by 4,400 Americans each day in 2019. Amid the opioid crisis, effective strategies to prevent and treat prescription opioid use disorder (OUD) are pressing. In preclinical models, the orexin system is recruited by drugs of abuse, and blockade of orexin receptors (OX receptors) prevents drug-seeking behavior. The present study sought to determine whether repurposing suvorexant (SUV), a dual OX receptor antagonist marketed for the treatment of insomnia, can treat two features of prescription OUD: exaggerated consumption and relapse. Methods: Male and female Wistar rats were trained to self-administer oxycodone (0.15 mg/kg, i. v., 8 h/day) in the presence of a contextual/discriminative stimulus (S^D) and the ability of SUV (0-20 mg/kg, p. o.) to decrease oxycodone self-administration was tested. After self-administration testing, the rats underwent extinction training, after which we tested the ability of SUV (0 and 20 mg/kg, p. o.) to prevent reinstatement of oxycodone seeking elicited by the S^D. Results: The rats acquired oxycodone self-administration and intake was correlated with the signs of physical opioid withdrawal. Additionally, females self-administered approximately twice as much oxycodone as males. Although SUV had no overall effect on oxycodone self-administration, scrutiny of the 8-h time-course revealed that 20 mg/kg SUV decreased oxycodone self-administration during the first hour in males and females. The oxycodone S^D elicited strong reinstatement of oxycodone-seeking behavior that was significantly more robust in females. Suvorexant blocked oxycodone seeking in males and reduced it in females. Conclusions: These results support the targeting of OX receptors for the treatment for prescription OUD and repurposing SUV as pharmacotherapy for OUD.

Alternative use of suvorexant (Belsomra®) for the prevention of alcohol drinking and seeking in rats with a history of alcohol dependence

Alcohol use disorder (AUD) is one of the most treatment-resistant medical conditions globally. The orexin (Orx) system regulates diverse physiological processes, including stress, and is a system of interest for the development of pharmaceuticals to treat substance use disorders, particularly AUD. The present study tested the ability of the dual orexin receptor antagonist suvorexant (SUV), marketed by Merck as Belsomra^®, for the treatment of insomnia, to decrease alcohol self-administration and the stress-induced reinstatement of alcohol-seeking behavior in male Wistar rats with a history of alcohol dependence. Rats were trained to orally self-administer 10% alcohol (30 min/day for 3 weeks) and were either made dependent via chronic intermittent alcohol vapor exposure (14 h ON, 10 h OFF) for 6 weeks or exposed to air (non-dependent). Starting on week 7, the effect of SUV (0-20 mg/kg, p.o.) was tested on alcohol self-administration at acute abstinence (8 h after vapor was turned OFF) twice weekly. A separate cohort of rats that were prepared in parallel was removed from alcohol vapor exposure and then subjected to extinction training for 14 sessions. Once extinction was achieved, the rats received SUV (0 and 5 mg/kg, p.o.) and were tested for the footshock stress-induced reinstatement of alcohol-seeking behavior. Suvorexant at 5, 10, and 20 mg/kg selectively decreased alcohol intake in dependent rats. Furthermore, 5 mg/kg SUV prevented the stress-induced reinstatement of alcohol-seeking behavior in dependent rats only. These results underscore the significance of targeting the Orx system for the treatment of substance use disorders generally and suggest that repurposing SUV could be an alternative approach for the treatment of AUD.

Looking Back, Looking Forward: Current Medications and Innovative Potential Medications to Treat Alcohol Use Disorder

This article is part of a Festschrift commemorating the 50th anniversary of the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Established in 1970, first as part of the National Institute of Mental Health and later as an independent institute of the National Institutes of Health, NIAAA today is the world's largest funding agency for alcohol research. In addition to its own intramural research program, NIAAA supports the entire spectrum of innovative basic, translational, and clinical research to advance the diagnosis, prevention, and treatment of alcohol use disorder and alcohol-related problems. To celebrate the anniversary, NIAAA hosted a 2-day symposium, "Alcohol Across the Lifespan: 50 Years of Evidence-Based Diagnosis, Prevention, and Treatment Research," devoted to key topics within the field of alcohol research. This article is based on Dr. Mason's presentation at the event. NIAAA Director George F. Koob, Ph.D., serves as editor of the Festschrift.

Alcohol dependence and withdrawal increase sensitivity of central amygdalar GABAergic synapses to the glucocorticoid receptor antagonist mifepristone in male rats

Aberrant glucocorticoid signaling via glucocorticoid receptors (GR) plays a critical role in alcohol use disorder (AUD). Acute alcohol withdrawal and protracted abstinence in dependent rats are associated with increased GR signaling and changes in GR-mediated transcriptional activity in the rat central nucleus of the amygdala (CeA). The GR antagonist mifepristone decreases alcohol consumption in dependent rats during acute withdrawal and protracted abstinence. Regulation of CeA synaptic activity by GR is currently unknown. Here, we utilized mifepristone and the selective GR antagonist CORT118335 (both at 10 μM) as pharmacological tools to dissect the role of GR on GABA transmission in male, adult Sprague-Dawley rats using slice electrophysiology. We subjected rats to chronic intermittent alcohol vapor exposure for 5–7 weeks to induce alcohol dependence. A subset of dependent rats subsequently underwent protracted alcohol withdrawal for 2 weeks, and air-exposed rats served as controls. Mifepristone reduced the frequency of pharmacologically-isolated spontaneous inhibitory postsynaptic currents (sIPSC) in the CeA (medial subdivision) without affecting postsynaptic measures in all groups, suggesting decreased GABA release with the largest effect in dependent rats. CORT118335 did not significantly alter GABA transmission in naive, but decreased sIPSC frequency in dependent rats. Similarly, mifepristone decreased amplitudes of evoked inhibitory postsynaptic potentials only in dependent rats and during protracted withdrawal. Collectively, our study provides insight into regulation of CeA GABAergic synapses by GR. Chronic ethanol enhances the efficiency of mifepristone and CORT118335, thus highlighting the potential of drugs targeting GR as a promising pharmacological avenue for the treatment of AUD.

Alcohol Use Disorder: TheRole of Medication in Recovery

The misuse of alcohol in the United States continues to take a large toll on society, resulting in the deaths of about 88,000 Americans per year. Moreover, it is estimated that nearly 14.6 million Americans currently meet diagnostic criteria for current alcohol use disorder (AUD). However, very few individuals receive treatment, with an even smaller portion receiving medications approved by the U.S. Food and Drug Administration (FDA) for the treatment of AUD, despite scientifically rigorous evidence showing the benefits of combining medication approved for treating AUD with evidence-based behavioral therapy. These benefits include higher rates of abstinence and less risk of relapse to heavy drinking, with associated improvements in medical and mental health and in quality of life. This review provides an overview of FDA-approved medications and “off-label” drugs for the treatment of AUD. The article emphasizes that AUD medical advice and prescription recommendations should come from professionals with training in the treatment of AUD and that treatment plans should consider medication in conjunction with evidence-based behavioral therapy. Finally, this review notes the limited number of medications available and the continued need for the development of new pharmacotherapies to optimize AUD recovery goals.

The future of translational research on alcohol use disorder

In March 2019, a scientific meeting was held at the University of California, Los Angeles (UCLA) Luskin Center to discuss approaches to expedite the translation of neurobiological insights to advances in the treatment of alcohol use disorder (AUD). A guiding theme that emerged was that while translational research in AUD is clearly a challenge, it is also a field ripe with opportunities. Herein, we seek to summarize and disseminate the recommendations for the future of translational AUD research using four sections. First, we briefly review the current landscape of AUD treatment including the available evidence-based treatments and their uptake in clinical settings. Second, we discuss AUD treatment development efforts from a translational science viewpoint. We review current hurdles to treatment development as well as opportunities for mechanism-informed treatment. Third, we consider models of translational science and public health impact. Together, these critical insights serve as the bases for a series of recommendations and future directions. Towards the goal of improving clinical care and population health for AUD, scientists are tasked with bolstering the clinical applicability of their research findings so as to expedite the translation of knowledge into patient care.

Glucocorticoid receptor modulators decrease alcohol self-administration in male rats

Alcohol use disorder (AUD) is associated with the dysregulation of brain stress and reward systems, including glucocorticoid receptors (GRs). The mixed glucocorticoid/progesterone receptor antagonist mifepristone and selective GR antagonist CORT113176 have been shown to selectively reduce alcohol consumption in alcohol-dependent rats. Mifepristone has also been shown to decrease alcohol consumption and craving for alcohol in humans with AUD. The present study tested the effects of the GR modulators CORT118335, CORT122928, CORT108297, and CORT125134 on alcohol self-administration in nondependent (air-exposed) and alcohol-dependent (alcohol vapor-exposed) adult male rats. Different GR modulators recruit different GR-associated transcriptional cofactors. Thus, we hypothesized that these GR modulators would vary in their effects on alcohol drinking. CORT118335, CORT122928, and CORT125134 significantly reduced alcohol self-administration in both alcohol-dependent and nondependent rats. CORT108297 had no effect on alcohol self-administration in either group. The present results support the potential of GR modulators for the development of treatments for AUD. Future studies that characterize genomic and nongenomic effects of these GR modulators will elucidate potential molecular mechanisms that underlie alcohol drinking in alcohol-dependent and nondependent states.

Effects of Tacrolimus and Other Immune Targeting Compounds on Binge-Like Ethanol Drinking in High Drinking in the Dark Mice

High Drinking in the Dark (HDID-1) mice represent a unique genetic risk model of binge-like drinking and a novel means of screening potential pharmacotherapies to treat alcohol use disorders (AUDs). We tested the effects of tacrolimus (0, 0.5, 1, and 2 mg/kg), sirolimus (0, 5, 10, and 20 mg/kg), palmitoylethanolamide (PEA; 0, 75, 150, and 225 mg/kg), and secukinumab (0, 5, 20, and 60 mg/kg) on binge-like ethanol intake (2-day, "Drinking in the Dark" [DID]) and blood alcohol levels (BALs) in HDID-1 mice. Tacrolimus reduced ethanol intake and BALs. Tacrolimus had no effect on water intake, but reduced saccharin intake. There was no effect of sirolimus, PEA, or secukinumab on ethanol intake or BALs. These results compare and contrast with previous work addressing these compounds or their targeted mechanisms of action on ethanol drinking, highlighting the importance of screening a wide range of models and genotypes to inform the role of neuroimmune signaling in AUDs.

The state of clinical outcome assessments for cannabis use disorder clinical trials: A review and research agenda

There is considerable variability in the use of outcome measures in clinical trials for cannabis use disorder (CUD), and a lack of consensus regarding optimal outcomes may have hindered development and approval of new pharmacotherapies. The goal of this paper is to summarize an evaluation of assessment measures and clinical endpoints for CUD clinical trials, and propose a research agenda and priorities to improve CUD clinical outcome assessments. The primary recommendation is that sustained abstinence from cannabis should not be considered the primary outcome for all CUD clinical trials as it has multiple limitations. However, there are multiple challenges to the development of a reliable and valid indicator of cannabis reduction, including the lack of a standard unit of measure for the various forms of cannabis and products and the limitations of currently available biological and self-report assessments. Development of a core toolkit of assessments is needed to both allow flexibility for study design, while facilitating interpretation of outcomes across trials. Four primary agenda items for future research are identified to expedite development of improved clinical outcome assessments for this toolkit: (1) determine whether minimally invasive biologic assays could identify an acute level of cannabis use associated with psychomotor impairment or other cannabis-related harms; (2) create an indicator of quantity of cannabis use that is consistent across product types; (3) examine the presence of cannabis-specific functional outcomes; and (4) identify an optimal duration to assess changes in CUD diagnostic criteria.

Gabapentin Enacarbil Extended-Release for Alcohol Use Disorder: A Randomized, Double-Blind, Placebo-Controlled, Multisite Trial Assessing Efficacy and Safety

BACKGROUND

Several single-site alcohol treatment clinical trials have demonstrated efficacy for immediate-release (IR) gabapentin in reducing drinking outcomes among individuals with alcohol dependence. The purpose of this study was to conduct a large, multisite clinical trial of gabapentin enacarbil extended-release (GE-XR) (HORIZANT^® ), a gabapentin prodrug formulation, to determine its safety and efficacy in treating alcohol use disorder (AUD).

METHODS

Men and women (n = 346) who met DSM-5 criteria for at least moderate AUD were recruited across 10 U.S. clinical sites. Participants received double-blind GE-XR (600 mg twice a day) or placebo and a computerized behavioral intervention (Take Control) for 6 months. Efficacy analyses were prespecified for the last 4 weeks of the treatment period.

RESULTS

The GE-XR and placebo groups did not differ significantly on the primary outcome measure, percentage of subjects with no heavy drinking days (28.3 vs. 21.5, respectively, p = 0.157). Similarly, no clinical benefit was found for other drinking measures (percent subjects abstinent, percent days abstinent, percent heavy drinking days, drinks per week, drinks per drinking day), alcohol craving, alcohol-related consequences, sleep problems, smoking, and depression/anxiety symptoms. Common side-effects were fatigue, dizziness, and somnolence. A population pharmacokinetics analysis revealed that patients had lower gabapentin exposure levels compared with those in other studies using a similar dose but for other indications.

CONCLUSIONS

Overall, GE-XR at 600 mg twice a day did not reduce alcohol consumption or craving in individuals with AUD. It is possible that, unlike the IR formulation of gabapentin, which showed efficacy in smaller Phase 2 trials at a higher dose, GE-XR is not effective in treating AUD, at least not at doses approved by the U.S. Food and Drug Administration for treating other medical conditions.

Gabapentin for the treatment of alcohol use disorder

INTRODUCTION

Alcohol misuse is the fifth leading risk factor for premature death and disability worldwide. Fewer than 10% of afflicted Americans receive pharmacological treatment for alcohol use disorder. Gabapentin is a calcium channel GABAergic modulator that is widely used for pain. Studies showing reduced drinking and decreased craving and alcohol-related disturbances in sleep and affect in the months following alcohol cessation suggest therapeutic potential for alcohol use disorder. Areas covered: Human laboratory and clinical studies assessing gabapentin for alcohol use disorder are reviewed. Data were obtained by searching for English peer-reviewed articles on PubMed, reference lists of identified articles, and trials registered on clinicaltrials.gov. Additionally, the mechanism of action of gabapentin specific to alcohol use disorder, and studies of gabapentin for alcohol withdrawal and non-alcohol substance use disorders are summarized. Expert opinion: Alcohol use disorder represents a challenge and large, unmet medical need. Evidence from single-site studies lend support to the safety and efficacy of gabapentin as a novel treatment for alcohol use disorder, with unique benefits for alcohol-related insomnia and negative affect, relative to available treatments. Proprietary gabapentin delivery systems may open a path to pivotal trials and registration of gabapentin as a novel treatment for alcohol use disorder.

Emerging pharmacotherapies for alcohol use disorder

The identification of different stages within the alcohol use disorder (AUD) cycle that are linked to neurocircuitry changes in pathophysiology associated with the negative emotional states of abstinence has provided a view of medication development for AUD that emphasizes changes in the brain reward and stress systems. Alcohol use disorder can be defined as a chronic relapsing disorder that involves compulsive alcohol seeking and taking, loss of control over alcohol intake, and emergence of a negative emotional state during abstinence. The focus of early medications development was to block the motivation to seek alcohol in the binge/intoxication stage. More recent work has focused on reversing the motivational dysregulations associated with the withdrawal/negative affect and preoccupation/anticipation stages during protracted abstinence. Advances in our understanding of the neurocircuitry and neuropharmacological mechanisms that are involved in the development and maintenance of the withdrawal/negative affect stage using validated animal models have provided viable targets for future medications. Another major advance has been proof-of-concept testing of potential therapeutics and clinical validation of relevant pharmacological targets using human laboratory models of protracted abstinence. This review focuses on future targets for medication development associated with reversal of the loss of reward function and gain in brain stress function that drive negative reinforcement in the withdrawal/negative affect stage of addiction. Basic research has identified novel neurobiological targets associated with the withdrawal/negative affect stage and preoccupation/anticipation stage, with a focus on neuroadaptive changes within the extended amygdala that account for the transition to dependence and vulnerability to relapse. This article is part of the Special Issue entitled "Alcoholism".

Existing and Future Drugs for the Treatment of the Dark Side of Addiction

The identification of a heuristic framework for the stages of the addiction cycle that are linked to neurocircuitry changes in pathophysiology includes the binge/intoxication stage, the withdrawal/negative affect stage, and the preoccupation/anticipation (craving) stage, which represent neuroadaptations in three neurocircuits (basal ganglia, extended amygdala, and frontal cortex, respectively). The identification of excellent and validated animal models, the development of human laboratory models, and an enormous surge in our understanding of neurocircuitry and neuropharmacological mechanisms have provided a revisionist view of addiction that emphasizes the loss of brain reward function and gain of stress function that drive negative reinforcement (the dark side of addiction) as a key to compulsive drug seeking. Reversing the dark side of addiction not only explains much of the existing successful pharmacotherapies for addiction but also points to vast new opportunities for future medications to alleviate this major source of human suffering.

Plasma profile of pro-inflammatory cytokines and chemokines in cocaine users under outpatient treatment: influence of cocaine symptom severity and psychiatric co-morbidity

The treatment for cocaine use constitutes a clinical challenge because of the lack of appropriate therapies and the high rate of relapse. Recent evidence indicates that the immune system might be involved in the pathogenesis of cocaine addiction and its co-morbid psychiatric disorders. This work examined the plasma pro-inflammatory cytokine and chemokine profile in abstinent cocaine users (n = 82) who sought outpatient cocaine treatment and age/sex/body mass-matched controls (n = 65). Participants were assessed with the diagnostic interview Psychiatric Research Interview for Substance and Mental Diseases according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR). Tumor necrosis factor-alpha, chemokine (C-C motif) ligand 2/monocyte chemotactic protein-1 and chemokine (C-X-C motif) ligand 12 (CXCL12)/stromal cell-derived factor-1 (SDF-1) were decreased in cocaine users, although all cytokines were identified as predictors of a lifetime pathological use of cocaine. Interleukin-1 beta (IL-1β), chemokine (C-X3-C motif) ligand 1 (CX3CL1)/fractalkine and CXCL12/SDF-1 positively correlated with the cocaine symptom severity when using the DSM-IV-TR criteria for cocaine abuse/dependence. These cytokines allowed the categorization of the outpatients into subgroups according to severity, identifying a subgroup of severe cocaine users (9-11 criteria) with increased prevalence of co-morbid psychiatric disorders [mood (54%), anxiety (32%), psychotic (30%) and personality (60%) disorders]. IL-1β was observed to be increased in users with such psychiatric disorders relative to those users with no diagnosis. In addition to these clinical data, studies in mice demonstrated that plasma IL-1β, CX3CL1 and CXCL12 were also affected after acute and chronic cocaine administration, providing a preclinical model for further research. In conclusion, cocaine exposure modifies the circulating levels of pro-inflammatory mediators. Plasma cytokine/chemokine monitoring could improve the stratification of cocaine consumers seeking treatment and thus facilitate the application of appropriate interventions, including management of heightened risk of psychiatric co-morbidity. Further research is necessary to elucidate the role of the immune system in the etiology of cocaine addiction.

Glucocorticoid receptor antagonism decreases alcohol seeking in alcohol-dependent individuals

Alcoholism, or alcohol use disorder, is a major public health concern that is a considerable risk factor for morbidity and disability; therefore, effective treatments are urgently needed. Here, we demonstrated that the glucocorticoid receptor (GR) antagonist mifepristone reduces alcohol intake in alcohol-dependent rats but not in nondependent animals. Both systemic delivery and direct administration into the central nucleus of the amygdala, a critical stress-related brain region, were sufficient to reduce alcohol consumption in dependent animals. We also tested the use of mifepristone in 56 alcohol-dependent human subjects as part of a double-blind clinical and laboratory-based study. Relative to placebo, individuals who received mifepristone (600 mg daily taken orally for 1 week) exhibited a substantial reduction in alcohol-cued craving in the laboratory, and naturalistic measures revealed reduced alcohol consumption during the 1-week treatment phase and 1-week post-treatment phase in mifepristone-treated individuals. Mifepristone was well tolerated and improved liver-function markers. Together, these results support further exploration of GR antagonism via mifepristone as a therapeutic strategy for alcoholism.

Gabapentin treatment for alcohol dependence: a randomized clinical trial

IMPORTANCE

Approved medications for alcohol dependence are prescribed for less than 9% of US alcoholics.

OBJECTIVE

To determine if gabapentin, a widely prescribed generic calcium channel/γ-aminobutyric acid-modulating medication, increases rates of sustained abstinence and no heavy drinking and decreases alcohol-related insomnia, dysphoria, and craving, in a dose-dependent manner.

DESIGN, PARTICIPANTS AND SETTING

A 12-week, double-blind, placebo-controlled, randomized dose-ranging trial of 150 men and women older than 18 years with current alcohol dependence, conducted from 2004 through 2010 at a single-site, outpatient clinical research facility adjoining a general medical hospital.

INTERVENTIONS

Oral gabapentin (dosages of 0 [placebo], 900 mg, or 1800 mg/d) and concomitant manual-guided counseling.

MAIN OUTCOMES AND MEASURES

Rates of complete abstinence and no heavy drinking (coprimary) and changes in mood, sleep, and craving (secondary) over the 12-week study. RESULTS Gabapentin significantly improved the rates of abstinence and no heavy drinking. The abstinence rate was 4.1% (95% CI, 1.1%-13.7%) in the placebo group, 11.1% (95% CI, 5.2%-22.2%) in the 900-mg group, and 17.0% (95% CI, 8.9%-30.1%) in the 1800-mg group (P = .04 for linear dose effect; number needed to treat [NNT] = 8 for 1800 mg). The no heavy drinking rate was 22.5% (95% CI, 13.6%-37.2%) in the placebo group, 29.6% (95% CI, 19.1%-42.8%) in the 900-mg group, and 44.7% (95% CI, 31.4%-58.8%) in the 1800-mg group (P = .02 for linear dose effect; NNT = 5 for 1800 mg). Similar linear dose effects were obtained with measures of mood (F2 = 7.37; P = .001), sleep (F2 = 136; P < .001), and craving (F2 = 3.56; P = .03). There were no serious drug-related adverse events, and terminations owing to adverse events (9 of 150 participants), time in the study (mean [SD], 9.1 [3.8] weeks), and rate of study completion (85 of 150 participants) did not differ among groups.

CONCLUSIONS AND RELEVANCE

Gabapentin (particularly the 1800-mg dosage) was effective in treating alcohol dependence and relapse-related symptoms of insomnia, dysphoria, and craving, with a favorable safety profile. Increased implementation of pharmacological treatment of alcohol dependence in primary care may be a major benefit of gabapentin as a treatment option for alcohol dependence.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00391716.

A translational approach to novel medication development for protracted abstinence

Alcohol dependence is a chronic relapsing disorder. Despite significant strides in the development of efficacious behavioral and pharmacological treatments for alcohol dependence, relapse rates remain very high. In this chapter, we review validated animal and human laboratory models for assessing risk of relapse in alcohol dependence and neurobiological treatment targets derived from such models. We suggest a translational approach to evaluate potential pharmacological treatments, using existing medications to validate and refine research paradigms across clinical and pre-clinical domains, with the aim of providing an accelerated framework for medications development in alcohol dependence. Lastly, empirical findings from proof-of-concept human laboratory studies are reviewed as we discuss the importance of selecting human laboratory models with predictive validity for the mechanism of action of the drug undergoing evaluation for efficacy in alcohol dependence.

Cohort study examining long-term respiratory health, career duration and racing performance in racehorses that undergo left-sided prosthetic laryngoplasty and ventriculocordectomy surgery for treatment of left-sided laryngeal hemiplegia

REASONS FOR PERFORMING STUDY

The risk of respiratory conditions, such as inflammatory airway disease (IAD) and exercise-induced pulmonary haemorrhage (EIPH), are thought to be higher in racehorses that undergo prosthetic laryngoplasty with ventriculocordectomy (PLVC) surgery to treat left-sided laryngeal hemiplegia (LLH) than in racehorses with normal laryngeal function. However, this has not been investigated formally owing to the difficulty of obtaining reliable follow-up data.

OBJECTIVES

To determine the incidence of respiratory conditions (IAD and EIPH), duration of racing career, number of starts and number of starts for which stakes money was earned in racehorses that had undergone PLVC surgery to treat LLH, compared with racehorses that did not have LLH or undergo any laryngeal surgery.

METHODS

A retrospective cohort study design was used, with surgical, clinical and race data of Thoroughbred racehorses obtained from the time of importation until retirement. The surgical cohort consisted of racehorses that had undergone PLVC for LLH and met specific inclusion criteria. Every surgical case was matched, according to trainer, year of import into Hong Kong and pre-import international handicap rating, to 2 unexposed racehorses.

RESULTS

Respiratory conditions, such as excessive tracheal mucus and epistaxis due to severe EIPH, were significantly increased in the surgical cohort, compared with the matched unexposed cohort (P values <0.001 and <0.004, respectively). Racing career duration in the surgical cohort was significantly shorter than in the unexposed cohort, which was primarily due to retirement because of epistaxis. The number of race starts was fewer in the surgical than in the unexposed cohort after surgery/matching, but the number of starts for which stakes money was earned was not significantly different.

CONCLUSIONS AND POTENTIAL RELEVANCE

Owners and trainers should be advised that racehorses with LLH that undergo PLVC surgery are at an increased risk of respiratory conditions (IAD and severe EIPH), which is likely to shorten their racing career compared to racehorses with normal laryngeal function. Racing performance in terms of race starts was significantly less in racehorses that had undergone PLVC surgery; however, the number of starts for which stakes money was earned was similar to those racehorses that were unexposed.

A proof-of-concept randomized controlled study of gabapentin: effects on cannabis use, withdrawal and executive function deficits in cannabis-dependent adults

There are no FDA-approved pharmacotherapies for cannabis dependence. Cannabis is the most widely used illicit drug in the world, and patients seeking treatment for primary cannabis dependence represent 25% of all substance use admissions. We conducted a phase IIa proof-of-concept pilot study to examine the safety and efficacy of a calcium channel/GABA modulating drug, gabapentin, for the treatment of cannabis dependence. A 12-week, randomized, double-blind, placebo-controlled clinical trial was conducted in 50 unpaid treatment-seeking male and female outpatients, aged 18-65 years, diagnosed with current cannabis dependence. Subjects received either gabapentin (1200 mg/day) or matched placebo. Manual-guided, abstinence-oriented individual counseling was provided weekly to all participants. Cannabis use was measured by weekly urine toxicology and by self-report using the Timeline Followback Interview. Cannabis withdrawal symptoms were assessed using the Marijuana Withdrawal Checklist. Executive function was measured using subtests from the Delis-Kaplan Executive Function System. Relative to placebo, gabapentin significantly reduced cannabis use as measured both by urine toxicology (p=0.001) and by the Timeline Followback Interview (p=0.004), and significantly decreased withdrawal symptoms as measured by the Marijuana Withdrawal Checklist (p<0.001). Gabapentin was also associated with significantly greater improvement in overall performance on tests of executive function (p=0.029). This POC pilot study provides preliminary support for the safety and efficacy of gabapentin for treatment of cannabis dependence that merits further study, and provides an alternative conceptual framework for treatment of addiction aimed at restoring homeostasis in brain stress systems that are dysregulated in drug dependence and withdrawal.

Craving in response to stress induction in a human laboratory paradigm predicts treatment outcome in alcohol-dependent individuals

RATIONALE

Alcohol dependence is associated with high rates of recidivism. Stress has been shown to increase alcohol craving in alcohol-dependent individuals, but the association between stress-induced craving and alcoholism treatment outcome is not well understood.

OBJECTIVE

The aim of the present study was to examine the relationship between strength of stress-induced alcohol craving in the human laboratory and subsequent drinking in a cohort of treatment-seeking, alcohol-dependent adults.

MATERIALS AND METHODS

This is a prospective study assessing stress-induced craving in the lab and subsequent treatment outcomes in alcohol-dependent subjects enrolled in a 12-week outpatient study. Stress was induced using a previously developed, individualized, audio recorded stress script and validated with objective (salivary cortisol) and subjective measures of distress. In vivo craving for alcohol was measured pre- and post-challenge using VAS.

RESULTS

Subjects were 28 (16 male, 12 female) alcohol-dependent outpatients. Greater stress-induced craving was associated with a blunted salivary cortisol response, significantly shorter time to alcohol relapse, higher mean drinks per week, fewer percent days abstinent, and lower rates of complete abstinence over the study duration (all p's < 0.05). Conversely, no demographic or baseline variables were significant predictors of any outcome variable.

CONCLUSIONS

These results suggest that greater stress-related increases in alcohol craving are associated with poorer alcohol treatment outcomes. The findings support the use of stress-induced craving as a predictor of alcohol relapse propensity. Furthermore, treatments that address high stress levels and the associated high levels of alcohol craving are likely to improve treatment outcomes in alcohol dependence.

An evidence based review of acute and long-term effects of cannabis use on executive cognitive functions

Cannabis use has been shown to impair cognitive functions on a number of levels-from basic motor coordination to more complex executive function tasks, such as the ability to plan, organize, solve problems, make decisions, remember, and control emotions and behavior. These deficits differ in severity depending on the quantity, recency, age of onset and duration of marijuana use. Understanding how cannabis use impairs executive function is important. Individuals with cannabis-related impairment in executive functions have been found to have trouble learning and applying the skills required for successful recovery, putting them at increased risk for relapse to cannabis use. Here we review the research on the acute, residual, and long-term effects of cannabis use on executive functions, and discuss the implications for treatment.

Acamprosate for alcohol dependence: a sex-specific meta-analysis based on individual patient data

BACKGROUND

It is unknown whether women derive comparable benefits and have a similar safety and tolerability profile as men from acamprosate, a widely prescribed drug for the maintenance of abstinence in alcohol dependence. The objective of this study was to assess sex-specific differences in the efficacy, safety, and tolerability of acamprosate in the treatment of women and men with alcohol dependence.

METHODS

A sex-specific meta-analysis was conducted based on individual patient data (IPD). Data were obtained from double-blind, randomized controlled trials with quantitative drinking measures in patients with alcohol dependence receiving oral acamprosate or placebo. Sources included PubMed, PsychInfo, and Cochrane electronic databases; reference lists from retrieved articles and presentations at professional meetings; and direct access to authors and companies who provided IPD.

RESULTS

Individual records were obtained from 1,317 women and 4,794 men who participated in 22 eligible studies conducted in 18 countries. IPD meta-analyses found a significant beneficial effect of acamprosate relative to placebo across all 4 efficacy end points: an incremental gain of 10.4% (95% CI 7.1 to 13.7, p < 0.001) in percentage of abstinent days, an incremental gain of 11.0% (7.4 to 14.6, p < 0.001) in percentage of no heavy drinking days, an odds ratio of 1.9 (1.6 to 2.2, p < 0.001) for rate of complete abstinence, and an odds ratio of 1.9 (1.6 to 2.3, p < 0.001) for rate of no heavy drinking, over the study duration. Acamprosate was also associated with significantly higher rates of treatment completion (p = 0.004) and medication compliance (p < 0.001) than placebo. Men and women did not differ on any measure of acamprosate efficacy, safety, or tolerability.

CONCLUSIONS

This sex-specific IPD meta-analysis provides evidence that acamprosate has a significant effect compared with placebo in improving rates of abstinence and no heavy drinking in both women and men with alcohol dependence. Further, acamprosate was associated with significantly higher rates of treatment completion and medication compliance than placebo among both women and men and had a comparable safety and tolerability profile.

The neurobiology, clinical efficacy and safety of acamprosate in the treatment of alcohol dependence

IMPORTANCE TO THE FIELD

Acamprosate, marketed under the brand name Campral, (Forest Pharmaceuticals, Inc., Saint Louis, MO, USA; Merck Sante s.a.s., Lyon, France) is an orally administered drug approved in the US and throughout much of the world for treating alcohol dependence. Its safety and efficacy have been demonstrated in a number of clinical trials worldwide and as with all pharmacotherapies for alcoholism, it is used in conjunction with psychosocial interventions.

AREAS COVERED IN THIS REVIEW

This article reviews the mechanism of action, clinical efficacy and safety of acamprosate in Phase I, II and III randomized controlled trials involving healthy and alcohol-dependent populations using published reports from 1984 to 2009.

WHAT THE READER WILL GAIN

This review provides an update of the mechanism of action and the safety and efficacy profile of acamprosate.

TAKE HOME MESSAGE

Acamprosate appears to act centrally to restore the normal activity of glutamatergic neurotransmission altered by chronic alcohol exposure. Acamprosate's excellent safety profile along with several pharmacokinetic and pharmacodynamic characteristics make it well suited for treating a broad population of alcohol-dependent patients.

Development of pharmacotherapies for drug addiction: a Rosetta stone approach

Current pharmacotherapies for addiction represent opportunities for facilitating treatment and are forming a foundation for evaluating new medications. Furthermore, validated animal models of addiction and a surge in understanding of neurocircuitry and neuropharmacological mechanisms involved in the development and maintenance of addiction - such as the neuroadaptive changes that account for the transition to dependence and the vulnerability to relapse - have provided numerous potential therapeutic targets. Here, we emphasize a 'Rosetta Stone approach', whereby existing pharmacotherapies for addiction are used to validate and improve animal and human laboratory models to identify viable new treatment candidates. This approach will promote translational research and provide a heuristic framework for developing efficient and effective pharmacotherapies for addiction.

Proof-of-concept human laboratory study for protracted abstinence in alcohol dependence: effects of gabapentin

There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs.

Effect of positive and negative affective stimuli and beverage cues on measures of craving in non treatment-seeking alcoholics

RATIONALE

Laboratory paradigms are useful for investigating mechanisms of human alcohol cue reactivity in a highly controlled environment. A number of studies have examined the effects of beverage exposure or negative affective stimuli on cue reactivity independently, but only a few have reported on interaction effects between beverage cue and affective stimuli, and none have evaluated the effects of positive stimuli on beverage cue reactivity.

OBJECTIVES

To assess independent and interactive effects of both positive and negative affective stimuli and beverage cue on psychophysiological and subjective measures of reactivity in alcohol dependence.

MATERIALS AND METHODS

A total of 47 non-treatment-seeking paid volunteers with current alcohol dependence participated in a within-subjects trial where each was exposed to a standardized set of pleasant, neutral, or unpleasant visual stimuli followed by alcohol or water cues. Psychophysiological cue-reactivity measures were obtained during beverage presentation, and subjective reactivity measures were taken directly following beverage presentation.

RESULTS

Mixed-effect models revealed a significant main effect of beverage and positive (but not negative) affective stimuli on subjective strength of craving and significant main effects of both positive and negative affective stimuli on ratings of emotionality. Despite the power to detect relatively small interaction effects, no significant interactions were observed between affect and beverage conditions on any reactivity measure.

CONCLUSIONS

A key finding of this study is that positive affective stimuli commonly associated with drinking situations can induce craving in the absence of alcohol cues. Main effects of beverage cue replicated results from previous studies. Beverage and affective cues showed no interaction effects.

Acamprosate in the treatment of alcohol dependence: clinical and economic considerations

Acamprosate has been commercially available in the USA since 2004 to treat alcohol dependence. Its safety and efficacy have been demonstrated in a number of clinical trials worldwide, which overall have shown significant improvements in abstinence compared with placebo. As with all alcoholism pharmacotherapies, acamprosate is used in conjunction with psychosocial interventions. One frequently described mechanism stipulates that acamprosate supports abstinence by normalizing the often protracted dysregulation of NMDA-mediated glutamatergic neurotransmission that follows chronic heavy alcohol use and withdrawal. This article reviews the clinical safety and efficacy of acamprosate, as well as results from recent pharmacoeconomic and human laboratory studies. These data elucidate the economic benefits of acamprosate, as well as its effects on cognition and alcohol-related sleep disturbances.

Effect of oral acamprosate on abstinence in patients with alcohol dependence in a double-blind, placebo-controlled trial: the role of patient motivation

This is the first US study to evaluate the clinical efficacy of acamprosate (Campral), a newly FDA-approved medication for maintaining abstinence in patients with alcohol dependence following alcohol withdrawal. We compared effects of the standard 2 g dose (n=258) and an exploratory 3 g dose of acamprosate (n=83) versus placebo (n=260), and evaluated drug safety in a double-blind, placebo-controlled 6-month trial conducted in 21 outpatient clinics across the US. Participants were 601 volunteers with current alcohol dependence recruited primarily by advertisement. All patients concomitantly received eight sessions of brief manual-guided counseling (www.alcoholfree.info). The main outcome measure was the percentage of alcohol-free days over the 6-month study. Self-report was validated by breath alcohol concentration, gamma-glutamyltransferase (GGT) and collateral informant interviews. The percentage of abstinent days did not differ significantly across groups in a priori analysis (54.3% for placebo, 56.1% for 2 g, 60.7% for 3 g). Post-hoc analysis controlling for baseline variables and treatment exposure found acamprosate was associated with a significantly higher percentage of abstinent days than placebo (52.3% for placebo, 58.2% for 2 g, 62.7% for 3 g; P=0.01), with an even greater effect in the subgroup of 241 patients having a baseline goal of abstinence (58.1% for placebo, 70.0% for 2 g, 72.5% for 3 g; P=0.02). There were no deaths or serious drug-related adverse events. The US study findings suggest that acamprosate is safe and well tolerated in a broadly inclusive sample of alcoholics and appears effective in populations of patients motivated to have a treatment goal of abstinence.

Understanding and treating alcohol dependence

This article represents the proceedings of a symposium presented at the 158th Annual Meeting of the American Psychiatric Association held in Atlanta, Georgia, on May 24, 2005. The organizer/chairman was Bankole A. Johnson, DSc, MD, PhD. The presentations included the following: (1) Neuropharmacological Basis of Alcohol Dependence, by George F. Koob, PhD; (2) Recent Developments in the Genetics of Alcohol Dependence, by Marc A. Schuckit, MD; (3) New Pharmacological Strategies for Treating Alcohol Dependence, by Barbara J. Mason, PhD; (4) New Medications: The Use of Anticonvulsants, Both Alone and in Combination, with Various Forms of Psychotherapy, by Bankole A. Johnson, DSc, MD, PhD; and (5) Differential Effects of Pharmacological Agents on Craving, by Nassima Ait-Daoud, MD.

Acamprosate in the treatment of alcohol dependence

Acamprosate is indicated for the maintenance of abstinence from alcohol in patients with alcohol dependence who are abstinent at treatment initiation in combination with psychosocial support. Acamprosate is a synthetic taurine analogue that seems to act centrally to restore the normal activity of glutamatergic neurotransmission altered by chronic alcohol exposure. Over the past 15 years, the safety and efficacy of acamprosate for alcohol dependence have been well established in multiple double-blind, placebo-controlled trials. Overall, acamprosate has been consistently associated with greater beneficial effects on measures of alcohol abstinence compared with placebo. Specifically, patients treated with acamprosate achieve greater rates of complete abstinence, longer times to first drink and/or increased duration of cumulative abstinence when compared with placebo. Acamprosate received approval by the US FDA for the treatment of alcohol dependence in July 2004 and is currently prescribed in 28 countries.

Combined pharmacotherapies and behavioral interventions for alcohol dependence: the COMBINE study: a randomized controlled trial

CONTEXT

Alcohol dependence treatment may include medications, behavioral therapies, or both. It is unknown how combining these treatments may impact their effectiveness, especially in the context of primary care and other nonspecialty settings.

OBJECTIVES

To evaluate the efficacy of medication, behavioral therapies, and their combinations for treatment of alcohol dependence and to evaluate placebo effect on overall outcome.

DESIGN, SETTING, AND PARTICIPANTS

Randomized controlled trial conducted January 2001-January 2004 among 1383 recently alcohol-abstinent volunteers (median age, 44 years) from 11 US academic sites with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnoses of primary alcohol dependence.

INTERVENTIONS

Eight groups of patients received medical management with 16 weeks of naltrexone (100 mg/d) or acamprosate (3 g/d), both, and/or both placebos, with or without a combined behavioral intervention (CBI). A ninth group received CBI only (no pills). Patients were also evaluated for up to 1 year after treatment.

MAIN OUTCOME MEASURES

Percent days abstinent from alcohol and time to first heavy drinking day.

RESULTS

All groups showed substantial reduction in drinking. During treatment, patients receiving naltrexone plus medical management (n = 302), CBI plus medical management and placebos (n = 305), or both naltrexone and CBI plus medical management (n = 309) had higher percent days abstinent (80.6, 79.2, and 77.1, respectively) than the 75.1 in those receiving placebos and medical management only (n = 305), a significant naltrexone x behavioral intervention interaction (P = .009). Naltrexone also reduced risk of a heavy drinking day (hazard ratio, 0.72; 97.5% CI, 0.53-0.98; P = .02) over time, most evident in those receiving medical management but not CBI. Acamprosate showed no significant effect on drinking vs placebo, either by itself or with any combination of naltrexone, CBI, or both. During treatment, those receiving CBI without pills or medical management (n = 157) had lower percent days abstinent (66.6) than those receiving placebo plus medical management alone (n = 153) or placebo plus medical management and CBI (n = 156) (73.8 and 79.8, respectively; P<.001). One year after treatment, these between-group effects were similar but no longer significant.

CONCLUSIONS

Patients receiving medical management with naltrexone, CBI, or both fared better on drinking outcomes, whereas acamprosate showed no evidence of efficacy, with or without CBI. No combination produced better efficacy than naltrexone or CBI alone in the presence of medical management. Placebo pills and meeting with a health care professional had a positive effect above that of CBI during treatment. Naltrexone with medical management could be delivered in health care settings, thus serving alcohol-dependent patients who might otherwise not receive treatment.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00006206.

Sertraline treatment of co-occurring alcohol dependence and major depression

BACKGROUND

Major depressive disorder occurs commonly in association with alcohol dependence, both in clinical samples and in the community. Efforts to treat major depressive disorder in alcoholics with antidepressants have yielded mixed results. This multicenter, double-blind, placebo-controlled trial of sertraline was designed to address many of the potential methodological shortcomings of studies of co-occurring disorders.

METHOD

Following a 1-week, single-blind, placebo lead-in period, 328 patients with co-occurring major depressive disorder and alcohol dependence were randomly assigned to receive 10 weeks of treatment with sertraline (at a maximum dose of 200 mg/d) or matching placebo. Randomization was stratified, based on whether initially elevated scores on the 17-item Hamilton Depression Rating Scale declined with cessation of heavy drinking, resulting in a sample of 189 patients with Hamilton Depression Rating Scale scores > or =17 (group A) and 139 patients with Hamilton Depression Rating Scale scores < or =16 (group B).

RESULTS

Both depressive symptoms and alcohol consumption decreased substantially over time in both groups. There were no reliable medication group differences on depressive symptoms or drinking behavior in either group A or B patients.

CONCLUSION

Despite careful attention to methodological considerations, this study does not provide consistent support for the use of sertraline to treat co-occurring major depressive disorder and alcohol dependence. The high rate of response among placebo-treated patients may help to explain these findings. Further research is needed to identify efficacious treatments for patients with these commonly co-occurring disorders.

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.

Costs and complications of equine castration: a UK practice-based study comparing 'standing nonsutured' and 'recumbent sutured' techniques

REASONS FOR PERFORMING STUDY

Clinicians are often asked to guide owners and trainers over the relative advantages and disadvantages of equine castration performed in either the standing horse with an open unsutured scrotal wound with healing by second intention, or a recumbent horse under general anaesthesia in aseptic conditions, with sutured scrotal skin allowing primary wound closure.

OBJECTIVES

To identify types and frequency of complications following the 2 differing approaches, and to compare the financial cost associated with each procedure, based on practice charges.

METHODS

Veterinary expenses of 217 horses castrated by a Newmarket equine veterinary practice over an 18-month period were analysed. Of these, Group 1 (n = 121) were castrated standing and nonsutured by one of 2 ambulatory clinicians and Group 2 (n = 96) castrated in recumbency, in aseptic equine hospital conditions.

RESULTS

Group 1 had a complication prevalence of 22% with no mortalities, and Group 2 a significantly lower complication prevalence of 6% (P = 0.001) with a mortality rate of 1%. The financial cost of Group 1, without complications, was approximately one-third of the cost of uncomplicated Group 2. However, the cost of Group 1 with complications increased to approximately two-thirds of the cost of an uncomplicated Group 2 castration.

CONCLUSIONS

Even though the complication prevalence for Group 1 castrations leaving an open scrotal wound was significantly higher than for a recumbent horse with a sutured scrotal wound in a hospital, the average cost of Group 1 was still less, even taking into account the additional follow-up costs associated with treating such complications.

POTENTIAL RELEVANCE

This report provides a benchmark for the outcome of 2 methods of castration based on a database obtained from particular circumstances within the practice involved. Further studies are required to corroborate and take into account future development in surgical and anaesthetic techniques.

How pilot studies improve large-scale clinical trials: lessons learned from the COMBINE Study

OBJECTIVE

The design of a clinical trial to evaluate a potential therapy requires decisions about issues that include safety, efficacy, measurement, feasibility and training. Experience from the COMBINE Study, which tests the combination of medications and behavioral therapies for alcohol dependence, is presented as an example of how pilot studies improve large-scale clinical trials.

METHOD

The COMBINE Pilot 1 inpatient study was designed to inform the main trial about the safety and tolerability of the doses of acamprosate (3 g/day) and naltrexone (100 mg/day) selected for study, alone and in combination. Pilot 2 was conducted as a feasibility study for the main trial, with the goals of (1) assessing the length of and compliance with research assessments, (2) developing methods for subject recruitment and staff training and (3) assessing the safety of the medications under less controlled outpatient conditions.

RESULTS

Results from Pilot 1 provided safety information to support testing the medications in an outpatient study and contributed to the decision to incorporate dose reductions into the main trial protocol to manage adverse events. The results of Pilot 2 formed a basis for (1) reducing the length of the assessment battery, (2) having staff fully trained and recruitment procedures established for the main trial and (3) extending the drug safety results of Pilot 1 to outpatient conditions similar to those of the main trial.

CONCLUSIONS

The COMBINE Study provides several examples of the successful application of pilot studies to inform the design of a clinical trial.

Acamprosate and naltrexone treatment for alcohol dependence: an evidence-based risk-benefits assessment

This paper provides an evidence-based risk-benefit assessment of acamprosate and naltrexone in the treatment of alcohol dependence. A risk-benefit assessment is based on the premise that the choice of treatment depends on a number of factors, notably the adverse event profile and efficacy. An evidence-based approach attempts to operationalize how such risk-benefit assessments are made to inform physician choices. This approach involves a systematic assessment of all published double-blind, placebo-controlled trials. Based on this review, we conclude acamprosate and naltrexone are both useful in the treatment of alcohol dependence. However, the two drugs act in different ways in the brain, and their clinical profiles are different. Treatment effects seem to be more reliable for acamprosate, and this drug is better tolerated. The safety of the two drugs in combination has been supported by two independent double-blind studies, and combination treatment may offer an advantage for some patients.