Algorithms Not Sole Factor in Prescribing for Obese Patients

There is currently no algorithm to guide clinicians in deciding which medication to choose to help promote weight loss in individuals with obesity. Rather, clinicians must take stock of a variety of factors when making treatment decisions for a particular patient.

Dr. Robert Kushner, MD, enumerated medications to treat obesity, and the factors that come into play when choosing among them during Obesity Week in Boston, MA.

Kushner, a professor of medicine and director of Northwestern University’s Comprehensive Center on Obesity, led off a pharmacotherapy-focused session held on November 5, 2014. He began by noting that all pharmacotherapy for obesity occurs in a larger framework: “We must have a clear understanding that medication only deals with a portion of the factors that affect obesity,” he noted.

Medication can affect the biological signaling that cues hunger signals, and it can promote or prolong satiety signals. However, beyond these neurochemical factors, the actual eating behaviors and the cognitive and social milieu for the behaviors comprise a key behavioral component. He pointed to the large body of work that shows the significant additive effect that lifestyle and behavior modification can have when used in conjunction with pharmacotherapy for obesity.

Kushner noted that clinical trial data can also provide some guidance for medication choice; in particular, clinicians should be familiar with inclusion and exclusion criteria used in studies for newer medications. These can provide a useful framework for pharmacotherapy decision making that takes patient comorbidities into account.

The newer pharmacotherapy options include two that are combination drugs: phentermine/topiramate and naltrexone/bupropion. These are new combination formulations of previously approved medications. A third, lorcaserin, is a novel selective serotonin 2C receptor agonist. All work centrally to reduce appetite and/or promote satiety. Liraglutide, a GLP-1 analog, is already approved for the treatment of type 2 diabetes; its approval to treat obesity is expected soon.

Medication side effect profiles are also important, he noted. Though all medications that combat obesity will carry some side effects, the profiles vary between agents. Dry mouth is a common side effect for the centrally acting agents; nausea, common with naltrexone/bupropion and liratglutide, tends to subside with time. Again, reviewing clinical trial data adverse event data for newer medications reveals which side effects are most common.

Considering which medication to consider for weight regain or failure to lose weight after bariatric surgery, Kushner said, is an “untapped, scientifically exciting area” that needs further deliberate investigation.

Kushner reminded the audience that for newer medications, the FDA has instituted “stop points” during pharmacotherapy, determined by assessing absolute weight loss after 3 months of therapy. For lorcaserin and naltrexone/bupropion, if weight loss is less than 5% of body weight at the 3-month point, the medication should be ceased and an alternative considered. For phentermine/topiramate, if weight loss is less than 3% at 3 months, the dose can be escalated and weight loss reevaluated after another 3 months. This prescribing strategy respects the evidence, especially strong for lorcaserin, that there is good early demarcation between those who are and are not likely to benefit from the medication.

Continuing the focus on practical pointers, Kushner encouraged clinicians to develop a sheet that outlines medication choices with known side effects for each, relative contraindications to their use, and expected benefits and results. This information can become a useful tool for education and shared decisonmaking between patient and clinician, and can bridge the practice gap until evidence-based algorithms are developed.