Addiction Drugs Help Shed Weight

According to the CDC, 34% of American adults over the age of 20 are overweight, with an additional 34% who are obese. Excess weight leads to a variety of health problems ranging from high blood pressure to cardiovascular disease. There are very few drugs on the market that target obesity.

In a study funded by Orexigen Therapeutics, researchers studied the effect of two drugs - naltrexone and buproprion - on weight loss. Researchers included study leader Prof Frank L Greenway MD, Ken Fujioka MD, Prof Raymond A Plodkowski MD, Prof Sunder Mudaliar MD, Maria Guttadauria MD, Janelle Erickson PhD, Dennis D Kim MD and Eduardo Dunayevich MD.

According to the Lancet, where the study results were published, Despite increasing public health concerns regarding obesity, few safe and effective drug treatments are available. Combination treatment with sustained-release naltrexone and bupropion was developed to produce complementary actions in CNS pathways regulating bodyweight. The Contrave Obesity Research I (COR-I) study assessed the effect of such treatment on bodyweight in overweight and obese participants."

The study combined the two drugs, used to combat addiction, in order to see if they would have an effect on weight loss.

The randomized, double-blind study involved 1742 participants between the ages of 18-65. The participants had uncomplicated obesity with a BMI between 30-45 or obesity with dyslipidaemia or hypertension with a BMI between 27-45. The participants were divided into three groups: one group receiving the placebo and the other two groups receiving different dose levels of the mixed drug - one naltrexone 16 mg plus 360 mg bupropion group and one naltrexone 32 mg plus 360 mg bupropion group. All groups took their pills twice per day. For the treatment groups, the dose was increased over a three week period to the treatment level. All three groups received diet and exercise advice to follow throughout the trial, which lasted a year.

While the groups all lost weight, the treatment groups lost more than the placebo. The mean weight loss in the placebo group was 1.3%, while the treatment group lost 6.1% (naltrexone 32 mg plus bupropion group) and 5.0% (naltrexone 16 mg plus bupropion group). Only 16% of participants taking the placebo lost over 5% of their bodyweight, compared to 48% taking the naltrexone 32 mg plus 360 mg bupropion and 39% in the naltrexone 16 mg plus 360 mg bupropion group.

The combination drug does come with a variety of side effects, including nausea, headaches, constipation, dry mouth, vomiting and dizziness.

The combination naltrexone and buproprion drug will be marketed as Contrave.

The study concluded that "A sustained-release combination of naltrexone plus bupropion could be a useful therapeutic option for treatment of obesity."

The Lancet: Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial