The Pharmacist’s Emerging Role in Weight Management: A Look into New Prescription Weight-Loss Medications

Approximately 69% of adult Americans aged 20 years and older are overweight or obese, according to data collected by the Centers for Disease Control and Prevention in 2009-2010.¹ Even more staggering is that nearly one third of adults in the United States are considered obese, causing an estimated $147 billion in US medical costs in 2008.²

To help increase the health and wellness of patients who are considered overweight or obese, pharmacists can encourage healthy lifestyles while providing patient care services such as medication therapy management. Pharmacists can also expand their role in helping patients lose weight through lifelong learning and staying current with new prescription medications that have been approved for weight reduction. In this discussion of newly approved therapies for chronic weight reduction, lorcaserin hydrochloride (Belviq) and phentermine/topiramate extended release (ER) (Qsymia) will be reviewed together using the 4 unique pillars of the pharmacy profession: indication, effectiveness, safety, and compliance.³

As the first US Food and Drug Administration (FDA)-approved medications for chronic weight management in more than a decade,^4,5 lorcaserin and phentermine/topiramate ER are indicated adjuncts to diet and exercise for chronic weight management. Patients who can safely use these medications for weight reduction include adults with a body mass index (BMI) >30 kg/m² with no weight-related comorbidities, or a BMI >27 kg/m² with at least 1 weight-related comorbidity, such as hypertension, type 2 diabetes, or dyslipidemia. Although these novel therapies are not options for everyone, they may provide clinically meaningful weight reduction in the patient populations mentioned above in as little as 12 weeks.^6,7

Dosages

In addition to its specific indications for use, phentermine/topiramate ER is accompanied by a detailed dose titration. After an initial 2 weeks at 3.75 mg/23 mg once daily, therapy should be increased to 7.5 mg/46 mg once daily. Following 12 weeks of therapy at the 7.5-mg/46-mg dose, effectiveness should be evaluated using the patient’s weight-loss percentage from baseline. If >3% weight reduction is achieved, the dose can be continued. If >3% weight reduction is not achieved, the dose can be further titrated to the maximum dose of 15 mg/92 mg, or discontinued. After an additional 12 weeks at the maximum dose, effectiveness should again be evaluated using a 5% weight reduction from baseline to determine whether to continue or discontinue the therapy.

In contrast, lorcaserin does not require a dose titration, eliminating the need for dose escalation, which may be an advantage in some patient populations. To correctly dose lorcaserin, patients should be initiated at the approved dose of 10 mg twice daily, and effectiveness should be evaluated after 12 weeks of therapy using a 5% decrease in body weight from baseline. Unfortunately, for both therapies it is unlikely that patients will achieve and sustain a clinically meaningful weight reduction if these markers from baseline are not attained.^6,7

Safety and Compliance

Several key points must be kept in mind to maximize patient outcomes through safety and compliance while minimizing the associated risks without limiting access to appropriate patients. An FDA-required Risk Evaluation and Mitigation Strategy (REMS) for phentermine/topiramate ER has been established to inform healthcare providers of the increased risk of teratogenicity, which includes a cleft lip with or without a cleft palate in infants exposed to topiramate in the first trimester. As such, phentermine/topiramate ER is only available through a network of certified pharmacies, which requires pharmacies to enroll and pharmacists to complete a training program and knowledge assessment. Pharmacists must ensure that the associated medication guide and patient brochure outlining the risk of birth defects is provided to the patient with every fill.

Lorcaserin, a serotonin 2C receptor agonist, is not associated with a REMS program. However, many prescribers and patients may have questions regarding valvular heart disease, a complication of fenfluramine, a component of Fen-Phen and a serotonin 2B receptor agonist, which was previously used for weight loss until it was withdrawn from the market in 1997.⁸ Encouragingly, in the Behavioral Modification and Lorcaserin for Overweight and Obesity Management (BLOOM) trial, lorcaserin was not associated with an increased risk of valvulopathy when compared with placebo.⁹ Regardless, pharmacists should still counsel patients who are using lorcaserin and experiencing the signs and symptoms of valvular heart disease, which include shortness of breath, edema, congestive heart failure, or a new cardiac murmur, to see their physician for immediate evaluation.⁷

Conclusion

As prescribers, pharmacists, and patients become more comfortable prescribing, dispensing, and using prescription medications for chronic weight management, additional opportunities for pharmacists to make direct and meaningful interventions with patients will arise. Because both lorcaserin and phentermine/topir­amate ER necessitate specific indicated uses, adequate trials for clinical effectiveness, safety requirements, and encouraged compliance, pharmacists can help patients achieve the health, wellness, and confidence that accompany weight loss by understanding the medications’ limitations and their adjunct role in chronic weight management.

References

1. Centers for Disease Control and Prevention. Obesity and Overweight. http://www.cdc.gov/nchs/fastats/overwt.htm. Accessed October 17, 2013.
   
2. Centers for Disease Control and Prevention. Adult Obesity Facts. http://www.cdc.gov/obesity/data/adult.html. Accessed October 17, 2013.
   
3. Cipolle RJ, Strand LM, Morley PC. Pharmaceutical Care Practice: The Clinician’s Guide. 2nd ed. New York, NY: McGraw-Hill; 2004.
   
4. US Department of Health and Human Services. US Food and Drug Administration. FDA approves Belviq to treat some overweight or obese adults [press release]. http://www.fda.gov/newsevents/newsroom/pressannouncements/ucm309993.htm. Accessed October 17, 2013.
   
5. US Department of Health and Human Services. US Food and Drug Administration. FDA approves weight-management drug Qsymia [press release]. http://www.fda.gov/newsevents/newsroom/pressannouncements/ucm312468.htm. Accessed October 17, 2013.
   
6. Belviq [package insert]. Woodcliff Lake, NJ: Eisai Inc; 2012.
   
7. Qsymia [package insert]. Mountain View, CA: VIVUS, Inc; 2013.
   
8. US Department of Health and Human Services. US Food and Drug Administra­tion. FDA announces withdrawal fenfluramine and dexfenfluramine (Fen-Phen) [press release]. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationfor PatientsandProviders/ucm179871.htm. Accessed October 17, 2013.
   
9. Smith SR, Weissman NJ, Anderson CM, et al. Multicenter, placebo-controlled trial of lorcaserin for weight management. N Engl J Med. 2010;363:245-256.