This is Dr. K, your War on Diabetes pharmacist, here to talk to you about a diabetes medication called Victoza. Victoza is an injectable drug that has been around for a relatively short amount of time – launched in the US in January of 2010. When you think of injectable medications for diabetes, your mind probably wanders to insulin. However, Victoza is not an insulin product. How does it work? Well, read along and we’ll learn all about it.
Victoza – How It Lowers Blood Sugar
Victoza is a GLP-1 receptor agonist. But what does that mean? If you read my previous post on Byetta, you’ve heard about this before, as it is another drug in this class. Victoza works by mimicking (or acting like) a hormone in your body called GLP-1. GLP-1 is a very important hormone that helps to lower your blood sugar, and it does this in a wide variety of ways. First, GLP-1 increases the amount of insulin released from your pancreas when your blood sugars are high. GLP-1 increases the size of your beta cells, the cells that are responsible for storing and releasing insulin. Also, GLP-1 makes the cells in your body more sensitive to insulin, meaning more glucose can get out of the blood and into the cells.
There are many more ways that GLP-1 works in your body. For instance, it slows down something that we call “gastric emptying,” which is a fancy term for the amount of time it takes for food that you’ve eaten to leave the stomach. Why is this important? Well, the faster the food leaves your stomach, the faster the carbohydrates you’ve eaten can be absorbed, which leads to a spike in your blood sugar. GLP-1 slows down this process so that the spike that you usually have after you eat will be later than normal.
Glucagon is a hormone in your body that works in the opposite way as insulin – it helps to raise your blood sugars when they are low. Obviously we don’t want too much glucagon working in your body though if you are trying to keep your blood sugars down. GLP-1 helps to control this by decreasing the amount of glucagon that your pancreas releases, which keeps your blood sugars at a healthier level. And another exciting thing about GLP-1: it actually helps you eat less by making your body feel full!
Victoza and Your A1C
From looking at various studies, it appears that Victoza alone can decrease A1c by up to 1.5% (so an A1c of 8.5% could go down to 7%). Some people have experienced a bit of weight loss while on Victoza (which makes sense because it can make you feel full faster), but the weight loss was very small, only about 2-5 pounds. Victoza is not considered a weight loss medication.
Victoza is given once daily as an injection into the stomach, thigh, or upper arm. The starting dose for adults is 0.6 mg once a day for one week, then the continuing dose is 1.2 mg daily. The dose can be increased to 1.8 mg if needed. If you have missed using your Victoza for 3 or more days, you should start over at 0.6 mg. This lower dose is given to decrease possible stomach upset.
Victoza Side Effects
The most common side effects seen with Victoza are headache, upper respiratory infection, nausea, diarrhea, upset stomach, and constipation (these were seen in more than 5% of patients). It is important to note that hypoglycemia (severe low blood sugar) was seen in 9.7% of patients, and this number was increased to up to 27.4% of patients on other medications that can cause low blood sugars (for example, insulin and sulfonylureas). Some of the more severe side effects seen with Victoza are hypersensitivity reactions, renal impairment, and pancreatitis.
Patients should watch for signs of pancreatitis when starting or increasing their dose of Victoza. The main symptom is persistent abdominal pain that may radiate to the back. This may or may not involve vomiting and fever. If you start to experience this, inform your doctor immediately.
Victoza also carries what we call a “black box warning,” which is a severe warning that details potential dangerous side effects if Victoza is not prescribed carefully. In animals that have been on higher doses of Victoza, and on it for long periods of time, Victoza has been linked to development of thyroid tumors. It is unknown whether Victoza carries these same risks in humans, so people at increased risks of these cancers should be very careful with Victoza.
Victoza – Who Should Not Take
There are no well-documented studies on the use of Victoza in pregnant women. Victoza is not recommended for use in children under 18 or in nursing mothers. If you are at an increased risk of developing thyroid cancer or pancreatitis, or if you have medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2, you should not take Victoza.
Victoza Drug Interactions
There are no major drug interactions listed in regards to Victoza, but always remember to talk to your doctor or pharmacist if you are considering starting any new medications, both prescription and over-the-counter. It is of note that, when combined with medications like insulin and sulfonylureas (glipizide, glyburide, glimepiride), your blood sugar levels might become too low, so be extra careful in monitoring your blood sugar levels when taking this combination.
As always, you should have your A1c monitored by your doctor to keep track of your war on diabetes. You should also be checking your blood sugars daily, or as directed by your doctor. Your doctor will also be checking your calcitonin levels and watching your thyroid in order to look for any abnormalities.
Victoza’s Place in Diabetes Therapy
Victoza is generally seen as a medication that is used after patients do not have the desired A1c after trying metformin, a sulfonylurea like glipizide or glimepiride, or a combination. It is usually not the first medication your doctor will start you on in your War on Diabetes, due to the cost and the fact that it has the added hassle of being an injection. If you want to read more about Victoza, you can learn about it here.