Is naltrexone an antidepressant

New appetite suppressant available soon

In addition, the amount of weight loss that can be achieved with nutrition, exercise and behavioral therapy is only a modest 3 to 5 percent of the initial value. In contrast, surgical stomach reduction leads to an average weight loss of 25 to 30 percent. But these interventions are not without risk. "The patients remain our patients even after the operation," said Blüher. Direct surgical complications are less of a priority than long-term risks such as insufficient supply, osteoporosis, wrinkling and psychological problems.

There is thus a need for effective pharmacotherapeutic agents to aid in weight loss. After rimonabant disappeared from the market due to an increased suicide risk and sibutramine due to an increase in cardiovascular risk, the market has been relatively empty. The lipase inhibitor orlistat, the two indirect sympathomimetics cathine hydrochloride and amfepramone, the GLP-1 receptor agonist liraglutide and naltrexone / bupropion are currently approved in Europe. Of these, the S3 guideline, »Prevention and Therapy of Obesity«, recommends orlistat as the only one. Liraglutide, originally developed as an anti-diabetic drug, which has also been approved for weight loss for two years, has been under evaluation for a year to be included in the guideline as a recommendation. "The hurdles for this are high," informed Blüher.

Mysimba, the newcomer to the anti-obesity market, has a central point of attack: the arcuate nucleus, a part of the hypothalamus in which hunger and reward are regulated. Proopiomelanocortin (POMC) is a messenger substance through which this regulation takes place. Bupropion directly stimulates POMC-dependent neurons and naltrexone amplifies this effect by suppressing a negative feedback mechanism mediated by β-endorphin. Both drugs are old friends, albeit not in obesity therapy. The norepinephrine and dopamine reuptake inhibitor bupropion is commercially available as an antidepressant and smoking cessation agent; the opioid antagonist naltrexone is used to assist addicts with drugs.

Each Mysimba prolonged-release tablet contains 8 mg naltrexone hydrochloride and 90 mg bupropion hydrochloride. The tablets should be swallowed whole, with liquid and preferably with food. The dosage is increased according to a fixed schedule during the first four weeks. First the patient takes one tablet in the morning for a week, then one tablet each morning and evening for a week. In the third week of treatment, two tablets should be taken in the morning and one tablet in the evening. From the fourth week onwards, the recommended maximum daily dose is reached with two tablets in the morning and two in the evening. After 16 weeks and annually thereafter, the attending physician should check whether continuation of the therapy is necessary.

The efficacy and safety of Mysimba were evaluated in four randomized, placebo-controlled studies with a total of 4536 participants. Treatment with Mysimba for 56 weeks along with diet and exercise resulted in 53 to 80 percent of patients being able to reduce their body weight by at least 5 percent; with diet, exercise, and placebo, only 22 to 60 percent managed this. In a study in which the patients took part in a particularly intensive sport and exercise program, both the test subjects in the verum and placebo groups achieved an above-average weight reduction. "This clearly shows that pharmacotherapy should only ever be an add-on to behavior modification," emphasized Blüher.