Kombiglyze XR is a once-daily oral tablet that combines saxagliptin (a DPP-4 inhibitor) with extended-release metformin for adults with type 2 diabetes. It delivers combined A1C reduction of approximately 1.0 to 1.8 percent, but the heart failure hospitalization signal associated with saxagliptin from the SAVOR-TIMI 53 trial has limited its modern use to patients without significant cardiac risk. Many clinicians now prefer Janumet or Jentadueto for DPP-4 + metformin combinations.
What Kombiglyze XR Contains
Kombiglyze XR is manufactured by AstraZeneca. Each tablet delivers two active ingredients:
- Saxagliptin — a DPP-4 inhibitor that prolongs the activity of incretin hormones GLP-1 and GIP, enhancing glucose-dependent insulin release and suppressing glucagon after meals. The SAVOR-TIMI 53 trial established cardiovascular non-inferiority overall but raised concerns about heart failure hospitalization.
- Metformin hydrochloride extended-release — a biguanide that reduces hepatic glucose production, modestly improves peripheral insulin sensitivity, and slows intestinal glucose absorption. The extended-release formulation reduces gastrointestinal side effects compared with immediate-release metformin and allows once-daily dosing.
Available Strengths
| Strength | Saxagliptin | Metformin XR |
|---|---|---|
| 2.5/1000 mg | 2.5 mg | 1,000 mg |
| 5/500 mg | 5 mg | 500 mg |
| 5/1000 mg | 5 mg | 1,000 mg |
Maximum daily dose is saxagliptin 5 mg plus metformin XR 2,000 mg, achieved by taking two of the 5/1000 mg tablets (split between dinner and another meal) or two 5/500 plus additional metformin.
Dosing Instructions
- Take once daily with the evening meal to reduce gastrointestinal side effects from metformin.
- Swallow whole — do not crush, split, or chew (the metformin XR matrix must remain intact).
- If a dose is missed and it is still the same day, take it as soon as remembered with food. Skip if it is close to the next dose.
- Maintain hydration throughout the day.
Who Kombiglyze XR Is For
Kombiglyze XR is approved for adults with type 2 diabetes as an adjunct to diet and exercise. Common scenarios:
- A1C remains above goal despite metformin monotherapy and the clinician prefers a DPP-4 inhibitor add-on
- Patient already takes saxagliptin (Onglyza) and metformin separately and wants to consolidate
- Patient has no significant heart failure risk and no other contraindications
It is generally avoided in patients with established heart failure, prior heart failure hospitalization, severely reduced left ventricular ejection fraction, or elevated NT-proBNP. It is not approved for type 1 diabetes, diabetic ketoacidosis, or pediatric patients.
How Well Kombiglyze XR Works
Pooled data from registration studies show:
- A1C reduction: approximately 1.0 to 1.8 percent in patients with poorly controlled type 2 diabetes.
- Weight change: approximately neutral — saxagliptin is weight-neutral, metformin may cause 1 to 2 kg loss.
- Fasting glucose: reduction of 25 to 45 mg/dL.
- Hypoglycemia risk: low when used without insulin or sulfonylureas.
- Cardiovascular outcomes: SAVOR-TIMI 53 trial of saxagliptin showed cardiovascular non-inferiority but a 27 percent relative increase in heart failure hospitalization (0.7 percent absolute increase).
For context on what these A1C reductions mean clinically, see our explainer on A1C levels.
The Heart Failure Signal
SAVOR-TIMI 53 enrolled 16,492 patients with type 2 diabetes and high cardiovascular risk. Heart failure hospitalization occurred in 3.5 percent of saxagliptin patients versus 2.8 percent of placebo. Subgroups at highest risk:
- Prior heart failure
- eGFR less than 60
- Elevated baseline NT-proBNP
- Age 65 or older
The FDA added a warning to saxagliptin product labels in 2016, and the ADA Standards of Care recommend avoiding saxagliptin in patients with heart failure. For most patients needing a DPP-4 + metformin combination, Janumet or Jentadueto are preferred alternatives.
Side Effects
| Side Effect | Source | Approximate Frequency |
|---|---|---|
| Nasopharyngitis | Saxagliptin | 5 to 7 percent |
| Headache | Saxagliptin | 6 percent |
| Upper respiratory tract infections | Saxagliptin | 5 to 6 percent |
| Dizziness | Saxagliptin | 3 to 4 percent |
| Diarrhea, nausea, abdominal pain | Metformin XR | 5 to 15 percent |
| Hypoglycemia (with insulin/sulfonylureas) | Both | Variable |
| Heart failure hospitalization (high-risk subgroups) | Saxagliptin | ~0.7% absolute vs placebo |
| Pancreatitis | Saxagliptin | Rare (less than 0.5 percent) |
| Severe joint pain | Saxagliptin (class effect) | Rare |
| Allergic reactions, angioedema | Saxagliptin | Rare |
| Vitamin B12 deficiency | Metformin (long-term) | 5 to 10 percent at 5+ years |
| Lactic acidosis | Metformin | Very rare (3 to 10 per 100,000) |
Contraindications and Warnings
- eGFR less than 30 mL/min/1.73 m squared: contraindicated due to metformin lactic acidosis risk.
- eGFR 30 to 45: avoid initiation; existing users may continue cautiously.
- Established heart failure or high risk: avoid or use with caution.
- Active diabetic ketoacidosis or type 1 diabetes.
- Severe hepatic impairment, acute or chronic metabolic acidosis, or chronic alcoholism.
- History of pancreatitis: use cautiously.
- Hold around iodinated contrast and major surgery (48 hours before and after).
- Pregnancy: not recommended in second or third trimester.
Drug Interactions
- Strong CYP3A4/5 inhibitors (ketoconazole, clarithromycin, ritonavir): limit saxagliptin to 2.5 mg — use Kombiglyze XR 2.5/1000 only.
- Strong CYP3A4 inducers (rifampin, carbamazepine, phenytoin) reduce saxagliptin efficacy.
- Cationic drugs (cimetidine, dolutegravir): increase metformin levels.
- Insulin and sulfonylureas increase hypoglycemia risk — doses may need reduction.
- Iodinated contrast: hold 48 hours before and after.
- Alcohol: increases lactic acidosis and hypoglycemia risk.
Cost and Insurance
Kombiglyze XR retails for approximately $500 to $650 per month at U.S. pharmacies. AstraZeneca’s manufacturer savings card can reduce out-of-pocket costs for commercially insured patients to as little as $0 to $20 per month, with annual savings limits. Medicare and Medicaid patients are not eligible but may qualify for income-based assistance. Many formularies have moved Kombiglyze XR to non-preferred tiers in favor of Janumet or Jentadueto due to the heart failure signal.
Storage
- Store at controlled room temperature 68 to 77 degrees F.
- Keep in original blister or bottle until use.
- Protect from moisture and heat.
- Do not crush, split, or chew tablets.
Kombiglyze XR vs Other DPP-4 + Metformin Combinations
| Feature | Kombiglyze XR | Janumet | Jentadueto |
|---|---|---|---|
| DPP-4 inhibitor | Saxagliptin | Sitagliptin | Linagliptin |
| Heart failure signal | Yes (SAVOR) | No (TECOS) | No (CARMELINA) |
| Renal dose adjustment of DPP-4 | Yes (eGFR less than 45) | Yes (eGFR less than 45) | No |
| A1C reduction | 1.0 to 1.8 percent | 1.5 to 2.0 percent | 1.0 to 1.8 percent |
| Dosing | Once daily (XR) | Twice daily IR or once XR | Twice daily IR or once XR |
| Generic outlook | Brand only | Generic expected 2026 | Brand only |
Among DPP-4 + metformin options, Kombiglyze XR is generally the least preferred today due to the saxagliptin heart failure signal. It remains reasonable for patients without heart failure risk, especially those already established and tolerating it well.
Place in Modern Type 2 Diabetes Care
ADA Standards of Care 2024 explicitly recommend avoiding saxagliptin in patients with heart failure and prioritizing SGLT2 inhibitors for patients with cardiovascular or kidney disease. Kombiglyze XR’s narrow niche today is patients with type 2 diabetes who:
- Have not achieved A1C goals on metformin alone
- Have no significant heart failure risk
- Need a weight-neutral, low-hypoglycemia oral option
- Are already on saxagliptin and metformin separately and want to consolidate
For broader treatment context, see our type 2 diabetes treatment options page.
Practical Considerations
- Take Kombiglyze XR consistently with the evening meal.
- Stay hydrated to support kidney function and reduce GI side effects.
- Watch for new shortness of breath, leg swelling, or unexplained weight gain — possible signs of heart failure.
- Stop and call your clinician for severe abdominal pain radiating to the back, persistent vomiting, or jaundice — symptoms of pancreatitis.
- Monitor for severe, persistent joint pain — a DPP-4 class effect.
- Inform any new clinician about Kombiglyze XR, especially before surgery or contrast imaging.
- Discuss vitamin B12 testing every 1 to 2 years on long-term metformin.
Switching from Kombiglyze XR
Patients with heart failure risk who are on Kombiglyze XR may consider switching to Janumet or Jentadueto with their clinician. The transition is straightforward — DPP-4 inhibitors are largely interchangeable from an A1C perspective. Patients with cardiovascular disease, heart failure, or chronic kidney disease may instead benefit more from switching to an SGLT2 inhibitor combination like Synjardy or Xigduo XR for the added outcome benefits.
Kombiglyze XR and Weight
Kombiglyze XR is approximately weight-neutral. Saxagliptin causes no weight change, and metformin may produce modest 1 to 2 kg loss. For larger weight loss, GLP-1 receptor agonists like semaglutide or tirzepatide are far more effective. See our overview of treatment options for context on alternatives.
The Bottom Line
Kombiglyze XR combines saxagliptin and extended-release metformin in a once-daily tablet for adults with type 2 diabetes. Combined A1C reduction of 1.0 to 1.8 percent comes with weight neutrality and low hypoglycemia risk. The saxagliptin heart failure hospitalization signal from SAVOR-TIMI 53 limits its modern use, particularly in patients with established heart failure or high risk. Janumet (sitagliptin) and Jentadueto (linagliptin) are generally preferred DPP-4 + metformin alternatives due to no heart failure signal. Common side effects include nasopharyngitis, headache, mild GI symptoms; rare risks include pancreatitis, severe joint pain, and lactic acidosis. Talk to your clinician about whether Kombiglyze XR fits your cardiovascular risk profile, or whether switching to a safer alternative would be appropriate.
