Dulaglutide, sold under the brand name Trulicity, and liraglutide, known as Victoza, are injectable medications used for managing type 2 diabetes. Both belong to a class of drugs called glucagon-like peptide-1 (GLP-1) receptor agonists. These therapies are prescribed to help improve blood sugar control in adults. They represent an option in the treatment landscape for diabetes, working with the body’s own systems to regulate glucose levels.
Mechanism of Action
Dulaglutide and liraglutide function by mimicking the action of a natural hormone in the body called GLP-1. When blood sugar levels are high, particularly after a meal, these drugs stimulate the pancreas to release insulin. Insulin helps cells absorb glucose from the bloodstream for energy. This process helps lower circulating blood sugar levels.
Their function extends beyond just insulin stimulation. These medications also suppress the secretion of glucagon, a hormone that tells the liver to release stored glucose, which prevents an unnecessary rise in blood sugar. A third action involves slowing down gastric emptying, the process by which food moves from the stomach into the small intestine. This delay contributes to a feeling of fullness, which can help reduce overall food intake.
Dosing and Administration
A primary difference between dulaglutide and liraglutide lies in their dosing frequency and the devices used for administration. Dulaglutide is administered as a once-weekly injection. It comes in a single-use, auto-injector pen that does not require the user to handle needles or measure the dose manually. The needle is pre-attached and retracts after the injection is complete.
Liraglutide, conversely, requires a once-daily injection. It is supplied in a multi-dose pen that can be used for several days. Patients using this medication must attach a new, disposable needle for each injection and dial the prescribed dose. The daily routine of liraglutide may appeal to those who prefer a consistent schedule, while the weekly injection is often seen as less burdensome.
Starting doses for both medications are low and are gradually increased. This approach helps the body acclimate to the drug and can minimize potential side effects. A healthcare provider determines the appropriate starting and maintenance dose based on an individual’s medical needs and response to the treatment.
Comparing Efficacy
The AWARD-6 trial, for instance, directly compared dulaglutide and liraglutide in patients with type 2 diabetes. In terms of blood sugar control, findings from this trial showed that the higher dose of dulaglutide (1.5 mg) was non-inferior to the higher dose of liraglutide (1.8 mg) in reducing HbA1c levels, a marker of long-term glucose control. Some analyses suggest dulaglutide may lead to slightly greater reductions in HbA1c.
Both medications are also associated with weight loss. In the AWARD-6 trial, patients taking liraglutide experienced slightly more weight loss at 26 weeks compared to those on dulaglutide. However, other studies have found their effects on weight reduction to be comparable. The amount of weight loss can vary among individuals.
Both drugs have demonstrated benefits in reducing the risk of major adverse cardiovascular events, such as heart attack and stroke, in patients with established heart disease. The LEADER trial for liraglutide and the REWIND trial for dulaglutide provided the evidence for these cardiovascular benefits. This makes them options for patients with both type 2 diabetes and heart conditions.
Side Effects and Safety Profiles
The most common side effects for both dulaglutide and liraglutide are gastrointestinal in nature. These include nausea, diarrhea, and vomiting, particularly when starting the medication or increasing the dose. These side effects are often mild to moderate and decrease as the body adjusts over time. Some data suggests that dulaglutide may be associated with a lower incidence of certain gastrointestinal issues compared to liraglutide.
Both medications carry a boxed warning from the U.S. Food and Drug Administration (FDA) regarding a potential risk of thyroid C-cell tumors. This warning is based on studies in rodents where the drugs caused these types of tumors; it is not known if they have the same effect in humans. Due to this risk, they are not recommended for people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.
Other serious but less common risks include pancreatitis, which is an inflammation of the pancreas. Patients are advised to watch for signs of pancreatitis, such as severe abdominal pain that may radiate to the back. Injection-site reactions, like redness or swelling, can also occur but are not severe.
Key Considerations for Patients
Choosing between dulaglutide and liraglutide often comes down to a balance of convenience, personal preference, and individual response. The once-weekly schedule of dulaglutide is a factor for those who prefer fewer injections, while others may be comfortable with the daily routine of liraglutide.
Tolerance of side effects is another consideration. While both have similar side effect profiles, an individual may tolerate one medication better than the other. Discussing potential gastrointestinal issues with a healthcare provider helps set expectations.
Insurance coverage and cost also influence the decision. Out-of-pocket expenses vary widely by insurance plan. Ultimately, the best choice is one made in partnership with a healthcare provider, taking into account a person’s lifestyle, medical history, and treatment goals.