(NaturalNews) Weight loss drugs may result only in minor weight loss, even after long-term use, according to a new study conducted by Brazilian and Canadian researchers and published in the British Medical Journal.
Researchers conducted meta-analyses of a number of studies conducted on the weight-loss drugs orlistat (marketed as Xenical and Alli), rimonabant (marketed as Acomplia) and sibutramine (marketed as Meridia), and found that users lost an average of less than 11 pounds, even after one to four years of use. Several key indicators of cardiovascular health were improved by taking the drugs, however.
Researchers examined 16 studies on orlistat, which operates by preventing the body from digesting fats. The average long-term user of orlistat lost only 7 pounds and had reduced diabetes risk, blood pressure and cholesterol. As many as 30 percent of users experienced digestive side effects.
Ten tests on sibutramine were also examined, along with four on rimonabant. Both drugs work by interrupting neural signals in the brain.
Sibutramine was found to reduce patients' weight by an average of only 9 pounds. In up to 20 percent of patients, however, it induced side effects including insomnia, nausea, and elevated blood pressure and pulse.
Rimonabant users lost an average of 11 pounds. Six percent of users experienced an elevated rate of mood disorders, however.
After receiving reports of psychiatric side effects such as anxiety and depression, the FDA refused to approve rimonabant for U.S. sale last year. Orlistat, in contrast, is approved for over-the-counter sale in a weakened form (Alli).
The move to sell weight loss drugs over the counter has drawn substantial criticism, including in an editorial accompanying the recent study.
"Selling anti-obesity drugs over the counter will perpetuate the myth that obesity can be fixed simply by popping a pill," Dr. Gareth Williams of the University of Bristol wrote.