Naltrexone and bulimic symptoms

Management of anorexia and bulimia nervosa: An evidence-based review

Anorexia nervosa and bulimia nervosa are primarily psychiatric disorders characterized by severe disturbances of eating behavior. Eating disorders are most prevalent in the Western culture where food is in abundance and female attractiveness is equated with thinness. Eating disorders are rare in countries like India. Despite a plethora of management options available to the mental health professionals, no major breakthrough has been achieved in recent years. Nutritional rehabilitation along with some form of re educative psychotherapy remains the mainstay of management of anorexia nervosa. In bulimia nervosa, both fluoxetine and cognitive behavior therapy have been found to be effective. Although the above-mentioned management options have been in use for decades, the active ingredient is still to be ascertained.

Treatment of bulimia nervosa: where are we and where are we going?

OBJECTIVE

The purpose of this article is to review the extant treatment literature on bulimia nervosa and to offer suggestions for future research directions.

METHOD

The available treatment studies regarding both pharmacotherapy and psychotherapy are reviewed.

RESULTS

Both pharmacotherapy and psychotherapy appear to play a role in the treatment of bulimia nervosa; however, available data suggest that cognitive behavioral therapy remains the treatment of choice.

CONCLUSION

Additional work is clearly indicated regarding assisted and unassisted self-help. An enhanced form of CBT and the integrative cognitive-affective therapy both deserve further study. New approaches need to be piloted. More research is needed on treatment modeling.

Emerging drugs for eating disorder treatment

Anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED) comprise the currently recognised eating disorders. Although distinct diagnostic entities, they share certain forms of comorbid psychopathology, particularly anxiety and mood disorders. BN and BED have been studied most intensively as targets for pharmacotherapy. The list of drugs tested in eating disorders is substantial; however, the number of therapeutic classes of medications tested in these conditions is relatively modest. Antidepressant medications, including tricyclic antidepressants, selective serotonin re-uptake inhibitors, as well as some of the novel antidepressants, have shown evidence of some therapeutic value in both BN and BED. Their efficacy in AN, however, has been disappointing. The pharmacological options for AN are very limited. The number of controlled trials that have been conducted is small, and the research that has been successfully completed has generally failed to demonstrate medication efficacy. Patients with BN typically show reduced binge eating and purging frequency in medication trials, but rarely attain abstinence. In BED, patients often measure the value of their medication therapy by its ability to stimulate weight loss, which is another area on which future pharmacotherapy may improve. Novel pharmacological interventions are needed for each of these conditions. Peptide hormones are increasingly being evaluated for eating disorder treatment, including ghrelin agonists, neuropeptide Y1 and -5 antagonists, orexin receptor antagonists, corticotropin-releasing factor receptor 2 antagonists, histamine 3 antagonists, melanocortin 4 receptor antagonists, beta3-adrenoceptor agonists, 5-hydroxytryptamine-2A antagonists and growth hormone agonists. Although these compounds are in early phases of clinical testing for eating disorder treatments, data from these studies will be instructive in the quest for effective pharmacotherapy for these conditions. An overview of the current pharmacotherapy options for eating disorders is presented with a discussion of the emerging potential treatments.

Towards the pharmacotherapy of eating disorders

The purpose of this review is to discuss pharmacological options for the treatment of patients with eating disorders. Sequentially described are pharmacotherapy studies of anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED). The quantity of drug trials performed with AN patients has been very limited. While the majority of studies have failed to show medication efficacy for the acute treatment of AN, there is data which suggests that fluoxetine hydrochloride may play a role in preventing relapse during maintenance therapy. Atypical antipsychotics, most often olanzapine, have shown promise in a number of uncontrolled studies. BN has been most extensively studied, with the majority of pharmacological trials focusing on antidepressants. Fluoxetine, at a dose of 60 mg/day, is FDA-approved for the treatment of BN. Psychotherapy, particularly cognitive behavioural therapy (CBT) is of well-established utility in BN and data suggests that the combination of an antidepressant plus CBT is superior to either treatment alone. Recently, there has been interest in the 5-HT3 antagonist, ondansetron, and the anticonvulsant, topiramate. BED investigators have focused largely on antidepressants, which may reduce symptoms of depression and augment psychotherapy. While sibutramine and topiramate have both been associated with weight loss in controlled trials, the former appears to be fairly well-tolerated and the latter appears to be responsible for the emergence of significant cognitive and peripheral nervous system side effects in some patients. Further pharmacological research with eating disorder patients is needed, particularly in the areas of AN and BED. Also, pharmacological augmentation strategies for those not responding to primary therapies should be explored.

Combining pharmacotherapy and psychotherapy in the treatment of patients with eating disorders

The available treatment literature supports a role for medication management in the treatment of both AN and BN. The data on BN are clearer and suggest that antidepressant therapy--fluoxetine being the drug most widely studied--is superior to treatment with placebo but less effective than CBT alone, with one such study suggesting that the combination may provide optimal treatment. Specific recommendations as to when to add or not add antidepressants to CBT have been made, although the rules suggested here have yet to be empirically tested. Although the data on AN are much more limited, information available suggests a lack of efficacy for SSRIs in patients with AN at low weight and considerable use for SSRIs when used in combination with psychotherapy for patients with AN following weight recovery. Where do we go from here? Several pressing issues require careful study. First, in the case of patients with AN, can other agents, in particular the new atypical antipsychotics, be useful in treating patients when they are at low weight? In terms of relapse prevention, can the available findings indicating a role for antidepressants in relapse prevention be replicated, and, if so, can predictor variables that are associated with antidepressant response be identified? In the case of BN, clinicians need to know more about the best possible way to sequence interventions. It has been proposed to add medication to CBT early in treatment if the response to CBT alone is thought to be inadequate. However, other models should be considered, such as stepped-care models in which self-help manuals are used in conjunction with medications. The advantage of these interventions is they could be made more widely available than CBT, which requires a specialist's care. Also, several other new agents, such as sibutramine, which is a drug with serotonin and norepinephrine reuptake inhibition effects, should be tested empirically in subjects with BN, given their pharmacologic profiles.

Pain tolerance in opioid addicts on and off naltrexone pharmacotherapy: a pilot study

Under certain experimental and clinical conditions, opioid antagonists have been demonstrated to have analgesic properties. In this open-label, nonrandomized, within-subject comparison, the effect of chronic treatment with the antagonist, naltrexone, on tolerance for experimental pain was evaluated in a small sample of male opioid addicts (N = 10) receiving naltrexone maintenance. Cold-pressor pain tolerance was measured during (> or = 6 weeks) and after discontinuation (> or = 1 week) of naltrexone treatment. Intra-subject comparison revealed that eight of the ten subjects were more pain tolerant (median + 20 sec) while receiving naltrexone. It is suggested that either midbrain opioid system upregulation in the presence of naltrexone or underlying individual differences in pain tolerance in persons with addictive disease provide potential explanations for these findings.

Investigational drugs for eating disorders

Anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED) each occur in about 0.5-1.5% of the population in westernised countries, and primarily affect women. At present, a variety of pharmacological treatments are used in addition to psychotherapy, with antidepressants being most the common. Currently available drugs, while helpful, fall far short of desired levels of efficacy. Based on current knowledge about neural mechanisms that regulate feeding behaviour, several classes of compounds are in development to treat eating disorders. These include cholecystokinin (CCK) antagonists, corticotropin-releasing hormone (CRH) antagonists, histamine-3 (H3) receptor antagonists, neuropeptide Y (NPY) antagonists, and a variety of serotonin uptake inhibiting drugs. Based on currently available effective treatments, it seems reasonable that the serotonin uptake inhibiting drugs might hold the greatest likelihood of benefit for these illnesses, but the receptor antagonists in development might provide substantial improvement in response rates.

New aspects of diagnosis and pharmacotherapy of eating disorders

This paper points out recent diagnostic features of bulimia and anorexia nervosa and of the recently defined 'binge eating disorder'. The pharmacologic treatment approaches for these conditions will be reviewed by discussing the results of randomized controlled studies. For anorexia nervosa (AN), the outcome of pharmacotherapy has been poor, in contrast to bulimia nervosa (BN) and binge eating disorder (BED), where pharmacological treatment, primarily with antidepressants, has proved to be effective, at least in the short run. However, long-term outcome studies are still awaited. (MJ Psych Clin Pract 1997; 1: 21-35).