Combination naltrexone-sustained release (SR) 32 milligram and bupropion SR 360 milligram (NB32) is a fixed-dose drug combination under investigation as a treatment for obesity. Bupropion is approved for depression and smoking cessation and is thought to function by increasing the level of dopamine (DA) activity in the brain, leading to a reduction in appetite and increase in energy expenditure. Naltrexone is approved for the treatment of opioid addiction and alcoholism. Naltrexone blocks opioid receptors in the brain and inhibits the reinforcing aspects of addictive substances, reducing their perceived reward. NB32 or a placebo was given to women with obesity for four weeks while they maintained their normal diet and exercise habits. Following the intervention, functional magnetic resonance imaging (fMRI) was assessed while subjects watched videos of their favorite foods being prepared while they were in a state of mild food deprivation. The study found that the subjects who took the NB32 had significantly different fMRI-assessed brain activity while watching the video than subjects who took placebo. NB32 led to greater activation in brain areas associated with self-control and internal awareness and caused less activation in the hypothalamic response to food cues. These effects may underlie NB32's therapeutic benefits in obesity.

Is he a healthy weight? Exposure to obesity changes perception of the weight status of others