By Candis M. Morello, Pharm D, CDE, FCSHP, Associate Professor of Clinical Pharmacy at UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences and Clinical Pharmacist at VASDHS; Courtney Shakowski, PharmD Candidate 2011 at UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences
My TCOYD Newsletter Vol. 32

In January of 2010, the Food and Drug Administration (FDA) approved the use of Victoza (liraglutide) in the United States in adults with type 2 diabetes in order to improve glycemic control in addition to diet and exercise. Now, Victoza joins Byetta (exenatide) in the class of drugs called GLP-1s.

What is Victoza?
GLP-1 is an incretin hormone. You may find yourself asking, “what are incretins?” Incretins are hormones released from the intestines after eating a meal that cause the pancreas to secrete insulin, decrease glucagon secretion and promote appetite suppression. One of the most important incretin hormones is the glucagon like peptide-1 (GLP-1). Unfortunately, if normal GLP-1 were to be administered, it would rapidly be deactivated by natural enzymes in the body. Novo Nordisk, the developer of Victoza, has figured out a way to trick the body by developing a drug that mimics the action of GLP-1, but different enough that it does not get rapidly degraded by the body’s enzymes.

How does Victoza work?
Victoza, a GLP-1 analog, works by mimicking the important functions of GLP-1 in the body. First, it causes the pancreas to secrete insulin in a glucose-dependent manner. This means when glucose concentrations rise, GLP-1 helps insulin secretion. Conversely, as glucose concentrations lower, Victoza stops working, preventing hypoglycemia. GLP-1 also decreases the secretion of glucagon from the pancreas. If glucagon increases, it leads to an increase in glucose production and increase in blood glucose.

Additionally, GLP-1 works in the brain to promote appetite suppression, which ultimately leads to sustained weight loss. Lastly, GLP-1 helps regulate the rhythmic contractions of the stomach, which are too fast in people with type 2 diabetes. This typically leads to the dumping of nutrients into the intestines and elevations in glucose. By replacing GLP-1, people with type 2 diabetes can achieve better glucose control after eating, as well as, weight loss.

Similarly, Byetta increases GLP-1 effects, but acts as a GLP-1 agonist. Currently, it requires twice daily injections compared to Victoza, which only requires one injection per day. However, a once weekly Byetta formulation is currently under review by the FDA.

Is Victoza right for me?
In addition to diet and exercise, Victoza will help people with type 2 diabetes achieve good glycemic control. The earlier glycemic control is achieved (targeting an A1C of less than 7% for most people) the better! This will help prevent the onset of long-term microvascular (small vessel) complications that can arise from poor glycemic control.

Before you start taking Victoza, tell your provider if you have had thyroid cancer, a history of pancreatitis or stones in your gallbladder. These conditions may predispose you to serious side effects of Victoza and you should avoid using this product. Remember to consult your provider before starting any new medication to ensure that a proper dose and schedule can be determined.

What can I expect?
Most importantly, you can expect a decreased A1C by 1.0% - 1.5%, which will help accomplish your goal of achieving glycemic control.

Furthermore, you can expect significant and sustained weight loss. This doesn’t mean you can quit your diet and exercise plan! As you know, regular exercise and maintaining a well-balanced diet are crucial to good glycemic control.

When first starting Victoza, you might also expect nausea, as it is the most common side effect. However, as your body adjusts to this medication within a few weeks, the nausea will decrease. In the mean time, eating small, frequent meals, chewing sugar free gum, or sucking on sugar free lozenges may help.

Victoza has little risk of causing low blood glucose when used alone. It is important to know that your risk for low blood sugar is higher if you take Victoza in combination with another medication that causes low blood sugar, such as glimepiride, glipizide or glyburide. Signs and symptoms of low blood sugar include: sweating, headache, confusion, irritability and hunger. Talk to your primary care provider about the medications you are taking that might cause low blood sugar, in addition to how to recognize and treat low blood sugar.

The Bottom Line
Insulin is not the only hormone in the body affected by diabetes. The incretin hormones are also affected. We now know an emerging class of drugs, GLP-1s, which in combination with diet and exercise help to achieve glycemic control and promote weight loss. This is great news because many of the current therapies for type 2 diabetes actually cause weight gain, which can be very frustrating! Keep your eyes open for long-acting GLP-1s. These agents would only require weekly injections rather than daily ones. This would mean another victory for people with type 2 diabetes!

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