Are Onglyza and Januvia the same? Understanding the Key Differences

October 10, 2025 •

3 min read

Despite both being used to treat type 2 diabetes and belonging to the same drug class, Onglyza (saxagliptin) and Januvia (sitagliptin) are not the same medication. These two DPP-4 inhibitors share a similar goal of controlling blood sugar but differ significantly in their active ingredients, potency, and safety profiles.

Quick Summary

Onglyza (saxagliptin) and Januvia (sitagliptin) are distinct DPP-4 inhibitor medications for type 2 diabetes, with differences in their active ingredients, dosages, and potential side effects. Onglyza carries specific FDA warnings regarding heart failure risk, which has not been found in studies comparing it to Januvia.

Key Points

Not the Same Medication: While both are DPP-4 inhibitors for type 2 diabetes, Onglyza contains saxagliptin, and Januvia contains sitagliptin.
Differing Safety Profiles: Onglyza carries an FDA warning for increased risk of heart failure hospitalization, especially in at-risk individuals, unlike Januvia.
Brand Name Discontinued: The brand-name Onglyza has been discontinued in the U.S., but its generic version, saxagliptin, remains available.
Dosage Differences: Onglyza's typical daily dose is 5mg, while Januvia's is 100mg, with dose adjustments necessary for renal impairment for both.
Longer Half-Life for Januvia: Januvia (sitagliptin) has a significantly longer plasma half-life (12.4 hours) compared to Onglyza (saxagliptin) at 3.1 hours.
Share Class Warnings: Both drugs carry warnings related to pancreatitis and severe joint pain, applicable to the entire DPP-4 inhibitor class.

What are DPP-4 inhibitors?

Both Onglyza and Januvia belong to a class of oral diabetes medications known as dipeptidyl peptidase-4 (DPP-4) inhibitors. This class of drugs works by targeting the body's incretin system, a hormonal pathway that helps regulate blood glucose levels. Here's how it works:

When you eat, your gut releases incretin hormones, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP).
These incretins stimulate the pancreas to produce more insulin in a glucose-dependent manner (meaning they are most active when blood sugar is high).
They also suppress the release of glucagon, a hormone that signals the liver to produce more glucose.
The DPP-4 enzyme rapidly deactivates these incretin hormones.

DPP-4 inhibitors block the DPP-4 enzyme, allowing incretin hormones to remain active longer, leading to increased insulin and reduced glucagon, thereby lowering blood sugar. This mechanism offers a low risk of hypoglycemia when used alone.

Onglyza vs. Januvia: A Side-by-Side Comparison

While their overall mechanism is similar, key distinctions exist between Onglyza and Januvia.

Active Ingredients

Onglyza contains saxagliptin, while Januvia contains sitagliptin.

Brand vs. Generic Availability

The brand-name Onglyza has been discontinued in the U.S., but its generic, saxagliptin, is available. Januvia is still a brand-name medication, with generic sitagliptin not yet widely available in the U.S..

Dosage and Administration

Both are taken once daily. Onglyza's typical dose is 5mg (2.5mg for moderate to severe renal impairment), while Januvia's is 100mg (lower doses for impaired kidney function).

Pharmacokinetics

Januvia has a longer half-life (around 12.4 hours) compared to Onglyza (3.1 hours), although Onglyza's binding allows for a 24-hour effect. Onglyza is metabolized by CYP3A4/5 enzymes, which can lead to drug interactions.

Efficacy

Clinical studies show comparable effectiveness in reducing HbA1c levels.

Comparison Table: Onglyza vs. Januvia


Feature	Onglyza (saxagliptin)	Januvia (sitagliptin)
Active Ingredient	Saxagliptin	Sitagliptin
Drug Class	Dipeptidyl Peptidase-4 (DPP-4) inhibitor	Dipeptidyl Peptidase-4 (DPP-4) inhibitor
Brand Availability	Discontinued (Generic available)	Available
Standard Daily Dose	5 mg	100 mg
Dosage for Renal Impairment	2.5 mg	50 mg or 25 mg
Common Side Effects	Cough, upper respiratory tract infection, urinary tract infection, headache	Joint pain, back pain, nausea, diarrhea, constipation, upper respiratory tract infection, headache
FDA Safety Warnings	Heart failure risk (Black Box Warning), pancreatitis, severe joint pain	Pancreatitis, severe joint pain
Heart Failure Risk	Increased risk of hospitalization for heart failure in susceptible patients	No increased risk in clinical studies, but warnings apply to the class
Half-Life	~3.1 hours	~12.4 hours
Key Drug Interactions	CYP3A4/5 inhibitors	Certain diuretics, antifungals

Side Effects and Safety Warnings

Both drugs have similar and differing side effects, with important safety warnings.

Common Adverse Effects

Both can cause headaches and respiratory/urinary infections. Onglyza is linked more to cough, while Januvia can cause muscle pain, nausea, and diarrhea.

Serious Adverse Effects

Both drugs carry a risk of pancreatitis and severe joint pain. A critical difference is Onglyza's FDA warning about an increased risk of hospitalization for heart failure in at-risk patients, which has not been observed with Januvia. Both can also cause severe allergic reactions.

Which Medication is Right for You?

The choice between Onglyza (or generic saxagliptin) and Januvia depends on individual health factors, history, and other medications, requiring consultation with a healthcare provider. Considerations include cardiovascular history (Onglyza's heart failure risk), kidney function (dosage adjustments needed for both), potential drug interactions (more noted with Onglyza), tolerance of side effects, and cost/availability.

Conclusion

Onglyza (saxagliptin) and Januvia (sitagliptin) are both DPP-4 inhibitors for type 2 diabetes but are not the same drug. Differences exist in their active ingredients, dosing, availability, and safety profiles. A key distinction is Onglyza's FDA warning regarding increased heart failure risk in susceptible patients, a concern not similarly found in Januvia studies. The decision of which to use is a medical one, based on a patient's individual profile. For more information, consult the FDA's Drug Safety Communications.

Frequently Asked Questions

The primary difference is their active ingredient. Onglyza uses saxagliptin, while Januvia uses sitagliptin. Though they belong to the same class of drugs (DPP-4 inhibitors) and work similarly, their chemical structures and safety profiles are not identical.

Yes, both Onglyza and Januvia are prescribed, along with diet and exercise, to help control high blood sugar levels in adults with type 2 diabetes.

Yes, the FDA has noted an increased risk of hospitalization for heart failure with Onglyza, a risk not similarly observed in clinical studies for Januvia. This is a key safety distinction between the two medications.

No, the brand-name Onglyza has been discontinued in the United States. However, the generic form, saxagliptin, remains available for prescription.

A generic version of Onglyza (saxagliptin) is available. Generic sitagliptin (Januvia) is not yet available in the U.S., though generics are approved in other regions.

Both can cause headache and upper respiratory infections. Onglyza is more commonly associated with cough, while Januvia may cause back and muscle pain, nausea, and diarrhea.

Their fundamental mechanism is the same: they both inhibit the DPP-4 enzyme to increase incretin hormone levels, which helps regulate blood sugar. However, their chemical structure and pharmacokinetics (like half-life) differ, leading to different dosage requirements and potential drug interactions.