Considering Qsymia for Obese Patients With Type 2 Diabetes

Considering Qsymia for Obese Patients With Type 2 Diabetes
Considering Qsymia for Obese Patients With Type 2 Diabetes
Evidence shows that the maximum dose of Qsymia is effective for obese patients with type 2 diabetes, but clinicians should still consider all factors.

I am very excited to write my first blog for the Endocrinology Advisor. I would like to first introduce myself. My name is Jennifer Clements and I am currently Interim Chair and Associate Professor of Pharmacy Practice at Presbyterian College School of Pharmacy. I graduated from Campbell University School of Pharmacy in 2006 and completed a PGY-1 ambulatory care residency in 2007.

After my residency, I was Assistant Professor of Pharmacy Practice at Shenandoah University. I joined the faculty at Presbyterian College School of Pharmacy in August 2012. I am board-certified in pharmacotherapy and ambulatory care. I also am a certified diabetes educator.

Over my short career, I have started or been involved with clinical pharmacy services in the area of diabetes, hypertension, hyperlipidemia, heart failure, obesity and endocrinology with the Department of Veterans Affairs and in private practice.

For my first blog, I decided to write about a study that I came across while I was preparing for an obesity presentation.

There have been several new drugs approved for obesity since July 2012. These medications include Belviq (lorcaserin), Qsymia (phentermine/topiramate) and Contrave (naltrexone/bupropion). Each medication is different in their mechanism of action, adverse event profile, potential for drug-drug interactions, contraindications and dosing. These agents may be equal in cost per tablet; however, the evidence should be evaluated in order to use these agents appropriately in clinical practice.

I want to focus on a study that was conducted specifically in patients with type 2 diabetes.

First, the manufacturer of Qsymia completed a phase 3 trial, known as the CONQUER trial. This particular study provided evidence regarding the efficacy and safety of Qsymia among overweight or obese individuals with hypertension, hyperlipidemia or type 2 diabetes. Approximately 68% of the study participants had type 2 diabetes.

At baseline, the average patient with type 2 diabetes had the disease for 5 years with an HbA1c of 6.8%. Therefore, clinically significant changes in HbA1c and fasting glucose levels may not have been observed in order to extrapolate to clinical practice.

A second study was done and published in Diabetes Care evaluating the maximum dose of Qsymia (phentermine 15 mg/topiramate 92 mg) among patients with obesity and type 2 diabetes over 56 weeks. These patients had the disease for 8 to 9 years, an HbA1c of 8.5% and BMI of 36.

In this study, the primary endpoints were reductions in HbA1c, fasting blood glucose levels and effect on weight parameters (i.e., reduction from baseline).

In the study, Qsymia was titrated to its maximum dose of phentermine 15 mg/topiramate 92 mg per day. The HbA1c decreased by 1.6% among study participants receiving the active drug. Due to education on lifestyle modifications for all study participants, the placebo arm had a 1.2% reduction in HbA1c (P <.05, compared with the active drug arm).

At the end the study, 53% of patients had an HbA1c less than 7%, whereas 23% of patients had an HbA1c of less than 6.5%. These results are similar to the CONQUER trial (51% with HbA1c less than 7.0%; 37% with HbA1c less than 6.5%).

The authors also reported any changes in diabetes medications among study participants. The adjustments were fairly equal among the active drug arm, a trend that was similar to that seen in the CONQUER trial. Overall, the participants in the placebo arm were more likely to need an increase in diabetes medications.

The maximum dose of Qsymia seems to be an appropriate option for obese patients with type 2 diabetes. However, patients need to be consulted and educated on potential side effects, such as impaired concentration, increased blood pressure (BP) and heart rate, and insomnia. Drug-drug interactions and contraindications should be reviewed before prescribing.

Bicarbonate and serum creatinine should be monitored at baseline and periodic follow-ups. 

While Qsymia is the most effective anti-obesity agent on the market, the cost of the drug should also be considered. It is estimated to be approximately $7.00 per day. If a patient is unable to afford Qsymia, the manufacturer does offer a discount program.

Again, I am very excited to start my blogging and writing for Endocrinology Advisor. I am open to any ideas for future blogs and articles. Please send me any of your ideas to [email protected]


  1. Gadde KM et al. Lancet. 2011;377(9774):1341-1352.
  2. Garvey WT et al. Diabetes Care. 2014;37(12):3309-3316.