Managing anti-obesity medications: Everything obstetrician-gynecologists need to know

Johanna Finkle, MD

Obstetrician–gynecologists treat patients across their lifespans and need to know how to address issues of weight at each stage. Whether an individual is of childbearing age, trying to conceive, pregnant, working through infertility, trying to lose weight after a birth, or experiencing symptoms of menopause, clinicians must be armed with the latest data, be up-to-speed on the latest weight management options, and be able to facilitate that conversation with their patients.

At a symposium at the American College of Obstetricians and Gynecologists 2024 Annual Clinical & Scientific Meeting in San Francisco, California, held May 17-19, 2024, Johanna Finkle, MD, clinical assistant professor at the University of Kansas Health System and weight management specialist, discussed the chronic nature of obesity and how it affects women at different ages. She shared clinical updates on the anti-obesity medications available and reviewed how to optimize medications that may contribute to unwanted weight gain.

A staggering 41.9% of the United States population lives with obesity, and it is considered to be a chronic, relapsing, treatable disease, according to the Obesity Medicine Association. It can present as “sick fat disease,” wherein it mainly expresses via endocrine and immune responses, or as “fat mass disease,” which puts more of a stress on the bones and joints and can cause tissue compression that limits mobility.

Finkle first pointed out the importance of using patient-first language when it comes to conversations about weight. “Just as we don't say ‘our diabetic patient;’ [it’s a] patient with diabetes.’ Similar for obesity…‘patients with obesity or pre-obesity,’” Finkle said.

Women may be at risk of weight gain during pregnancy, if they have polycystic ovarian syndrome, or during perimenopause or menopause. Menopause, in particular, can affect weight because of the dip in estrogen, which is often followed by a decrease in activity and diet changes, Finkle explained.

Clinicians should ensure their patients understand the pillars of weight management, which are nutrition, physical activity, behavior modification, medications, and medical intervention or surgery. The anti-obesity medication landscape has exploded in popularity over the last few years, with drugs like semaglutide and other glucagon-like peptide (GLP-1) receptor agonists getting a lot of public attention.

“These medications…focus on CCK, GLP-1 and PYY. Those are the hormones that control satiety and hunger, especially the GLP-1, [it] goes up to the brain and says, ‘I’m full,’” Finkle said. “These are the hormones that are being targeted for current research and some of those medications are already being used.”

Finkle stressed that one size does not fit all for treatment, and it is important to find out a patient’s ultimate goals, whether any comorbidities exist, and how the medications can be layered or tailored. For example, if a patient needs short-term weight loss, then phentermine, diethylpropion, phendimetrazine, and benzphetamine may be options. Long-term options include orlistat, phentermine/topiramate ER, naltrexone HCI/bupropion HCI ER, liraglutide, semaglutide, or tirzepatide. It is important to note pregnancy and lactation are contraindications for all anti-obesity medications.

For the GLP-1 class of anti-obesity medications, contraindications include personal or family history of medullary thyroid cancer, MEN II syndrome, or hypersensitivity to the drug class. Risks and side effects include pancreatitis, suicidal ideation, gallstones, nausea/vomiting, diarrhea/constipation, dyspepsia, and increased heart rate. Delivered as subcutaneous injections in pre-loaded syringes, GLP-1s increase central satiety, decrease hunger, and slow gastric emptying.

Liraglutide is administered daily in a maximum dose of 3.0 mg (starting dose 0.6 mg, titrated weekly) and patients can expect about 4% weight loss over 16 weeks or they’re considered to be a non-responder. Semaglutide, meanwhile, is administered weekly, which makes it a more attractive option. The dose maximum is 2.4 mg (starting dose 0.25 mg, titrated monthly) and must result in 5% weight loss over 16 weeks or a patient is considered a non-responder. In practice, however, patients are experiencing more like a 15% weight reduction, with 32% of patients losing > 20% body weight. Additionally, the SELECT study of 17,000 patients with obesity taking semaglutide showed a 20% cardiac risk reduction.

The new kid on the block is tirzepatide, which is shaping up to be even more effective than its predecessors. This is a GLP-1 plus a glucose-dependent insulinotropic polypeptide, so not only does it increase central satiety and slow gastric emptying, but it also increases insulin secretion, decreases glucagon secretion, and increases lipolysis and fatty acid synthesis. It is administered weekly in a maximum dose of 15 mg (starting dose 2.5 mg, titrated monthly). In clinical studies, a whopping 91% of patients experienced a > 5% weight loss, while 56% of patients saw > 20% weight reduction.

Selecting the right medication for your patient often comes down to cost, Finkle said. She recommends laying out all the information and helping patients come to a decision that works best for them. The GLP-1s are currently the most effective anti-obesity medications available but also the most costly. In development are a few oral formulations, including oral semaglutide.

Clinicians should also understand what other medication might be contributing to weight gain, such as birth control (medroxyprogesterone acetate), anti-hypertensives (beta blockers), anti-depressants (amitriptyline, paroxetine, venlafaxine, trazadone), mood stabilizers (gabapentin, lithium, valproate, carbamazepine), migraine medication (amitriptyline, beta blockers), or sleep medication (diphenhydramine, zolpidem).

An important clinical pearl to remember is to code for the complications, not for obesity due to excess calories, as that code (E66.0) is non-billable. Clinicians should always remember and discuss the pillars of weight management with patients, and optimize other medication regimens.

References

Finkle J. Anti-obesity medications: what obstetrician–gynecologists need to know. Symposium at: The American College of Obstetricians and Gynecologists 2024 Annual Clinical & Scientific Meeting. San Francisco, CA. May 17-19, 2024.