Lifestyle changes result in the least weight loss and may be safest, while surgery provides the most weight loss and has the greatest risk. Antiobesity medications, especially the newer ones used in combination with lifestyle changes, can provide significant and sustained weight loss with manageable side effects, said Daniel Bessesen, MD, a professor in the endocrinology, diabetes, and metabolism at University of Colorado at Denver, Aurora.
New and more effective antiobesity medications have given internists more potential options to discuss with their patients, Dr. Bessesen said. He reviewed the pros and cons of the different options.
Medications are indicated for patients with a body mass index greater than 30, including those with a weight-related comorbidity, Dr. Bessesen said. The average weight loss is 5%-15% over 3-6 months but may vary greatly. Insurance often does not cover the medication costs.
Older FDA-approved antiobesity medications
Phentermine is the most widely prescribed antiobesity medication, partly because it is the only option most people can afford out of pocket. Dr. Bessesen presented recent data showing that long-term use of phentermine was associated with greater weight loss and that patients continuously taking phentermine for 24 months lost 7.5% of their weight.
Phentermine suppresses appetite by increasing norepinephrine production. Dr. Bessesen warned that internists should be careful when prescribing it to patients with mental conditions, because it acts as a stimulant. Early studies raised concerns about the risk of cardiovascular disease (CVD) in patients taking phentermine. However, analysis of data from over 13,000 individuals showed no evidence of a relationship between phentermine exposure and CVD events.
“These data provide some reassurance that it could be used in patients with CVD risk,” he noted. Phentermine can also be combined with topiramate extended release, a combination that provides greater efficacy (up to 10% weight loss) with fewer side effects. However, this combination is less effective in patients with diabetes than in those without.
Additional treatment options included orlistat and naltrexone sustained release/bupropion SR. Orlistat is a good treatment alternative for patients with constipation and is the safest option among older anti-obesity medications, whereas naltrexone SR/bupropion SR may be useful in patients with food cravings. However, there is more variability in the individual-level benefit from these agents compared to phentermine and phentermine/topiramate ER, Dr. Bessesen said.
Newer anti‐obesity medications
Liraglutide, an agent used for the management of type 2 diabetes, has recently been approved for weight loss. Liraglutide causes moderate weight loss, and it may reduce the risk of CVD. However, there are tolerability issues, such as nausea and other risks, and Dr. Bessesen advises internists to “start at low doses and increase slowly.”
Semaglutide is the newest and most effective antiobesity drug approved by the Food and Drug Administration, providing sustained weight loss of 8% for up to 48 weeks after starting treatment. Although its efficacy is lower in patients with diabetes, Dr. Bessesen noted that “this is common for antiobesity agents, and clinicians should not refrain from prescribing it in this population.”
Setmelanotide is another new medication approved for chronic weight management in patients with monogenic obesity. This medication can be considered for patients with early-onset severe obesity with abnormal feeding behavior.
Commenting on barriers to access to new antiobesity medications, Dr. Bessesen said that “the high cost of these medications is a substantial problem, but as more companies become involved and products are on the market for a longer period of time, I am hopeful that prices will come down.”