The Food and Drug Administration (FDA) recently approved Qsymia (phentermine and topiramate extended release) and Belviq (lorcaserin hydrochloride) weight loss pills for management of obesity. Both Qsymia and Belviq are combined with a reduced calorie diet and exercise for long term weight management in adult patients with a body mass index (BMI) of 30 or greater or adult overweight patients with at least one weight related condition such as high blood pressure, type II diabetes, or high cholesterol. This article will highlight some distinguishing facts about the two medications so that patients and physicians can make an informed decision when selecting a weight loss pill.

How do Qsymia and Belviq work?

Qsymia is a new formulation that consists of two separate approved drugs. The first component is a migraine and seizure medication called topiramate that causes weight loss by reducing appetite, increasing feelings of fullness, reducing the taste of food, and increasing burning of calories. The second component is called phentermine, which suppresses appetite by triggering the release of a brain chemical (hormone) called leptin, which regulates appetite.

Belviq is a serotonin 2C receptor agonist with an unknown mechanism of action. Belviq possibly decreases food consumption by making a person feel full even after consuming less food than usual. It may work by increasing levels of serotonin, a neurotransmitter (brain chemical) that nerves use for communicating.

Both Qsymia and Belviq are approved for weight management in obese and overweight adults.

Efficacy of Qsymia

Weight Loss at One Year in Study 1 and 2

• With the recommended dose of 7.5 mg/46 mg, average weight loss was 6.7% over placebo.
• With the recommended dose of 15 mg/92 mg, average weight loss was 8.9%over placebo.
• 62%-69% of patients that received Qsymia lost an average of 5% body weight in comparison to 20% that received placebo.

Efficacy of Belviq

Weight Loss at 1 year

• Patient treated with Belviq lost an average of 3% to 3.7% of body weight.
• In patient without type 2 diabetes, 47% lost an average of 5% bodyweight compared to 23% on placebo.
• In patient with type 2 diabetes, 38% lost average 5% of bodyweight compared to 16% in placebo.

How are Qsymia and Belviq administered?

Qsymia 3.75 mg/23 mg is administered daily for 14 days, then increase to 7.5 mg/46 mg daily. Discontinue or escalate dose if 3% weight loss is not achieved after 12 weeks on maximum daily dose of 7.5 mg/46 mg or if 5% weight loss is not achieved after 12 weeks on maximum daily dose of 15 mg/92 mg.

Belviq 10 mg is administered orally twice a day with or without food. Patients must be evaluated by week 12 of therapy. Discontinue therapy if a patient has not lost at least 5% from baseline bodyweight by week 12.

Qsymia side effects

• Common: headache, colds, paresthesia (tingling or pricking sensation in hands and feet), dizziness, insomnia, constipation, dry mouth, disturbance in metabolism
• Serious: fetal toxicity, increased heart rate, suicidal behavior, acute angle closure glaucoma, mood and sleep disorder, cognitive impairment, disturbance in metabolism

Belviq side effects

• Common: headache, upper respiratory tract infections, colds, dizziness, fatigue, nausea, dry mouth, constipation, hypoglycemia (low blood glucose), back pain, cough, and fatigue
• Serious: serotonin syndrome, valvular heart disease, cognitive impairment, psychiatric disorders, severe hypoglycemia, decreased heart rate, prolactin elevation, decreased number of white blood cells

Patient who should NOT use Qsymia

• Pregnancy
• Glaucoma
• Hyperthyroidism
• During or within 14 days following the administration of monoamine oxidase inhibitors
• Patients with unstable heart disease or high risk for stroke

Patient who should NOT use Belviq

• Pregnancy
• History of heart problems
• Patient who’s currently on other therapy that increase serotonin such as antidepressants and migraine medications
• Men with conditions that predispose them to erections lasting more than four hours (priapism) including leukemia, sickle cell anemia, and multiple myeloma

Cost of Qsymia

Wholesale price of Qsymia (the price pharmacies will pay for a 30-day supply) is:

• Low dose (3.75 mg phentermine/23 mg topiramate) -- $120.00
• Recommended dose (7.5 mg/46 mg) -- $135.62
• Three-quarter dose (11.25 mg/69 mg) -- $162.74
• Top dose (15 mg/92 mg) -- $183.90

Cost of Belviq

Current price of Belviq is $200 a month.

Conclusion

The epidemic of obesity threatens the overall wellbeing of patients, especially for those with co-morbidities. With the FDA approval of Qsymia and Belviq weight loss pills, patients who are obese can potentially benefit from these two therapies. However, important practices and monitoring is extremely critical to ensure the safety and efficacy of both medications. To dispense Qsymia, pharmacies and prescribers must be certified through special training and a Risk Evaluation and Mitigation Strategy (REMS) program must be followed. Qsymia and Belviq are available.

Author: Mai Nguyen, PharmD Candidate 2013

References:

FDA Prescribing Information for Qsymia

FDA Prescribing Information for Belviq

Liscinsky, Morgan. "News & Events. FDA Approves Weight-management Drug Qsymia. FDA U.S. Food and Drug Administration, 12 July 2012. Web. 07 Nov. 2012.

Yao, Stephanie. "News & Events. FDA Approves Belviq to Treat Some Overweight or Obese Adults. FDA U.S. Food and Drug Administration, 27 July 2012. Web. 07 Nov. 2012.

Grohol, John M. Qsymia and Belviq Drugs for Obesity, Weight Loss | Psych Central. Psych Central.com. N.p., 01 Aug. 2012. Web. 07 Nov. 2012.