Definition: A fixed-dose combination is one tablet that holds two drugs at set strengths. Janumet (sitagliptin and metformin), Synjardy (empagliflozin and metformin) and Xigduo XR (dapagliflozin and metformin) are examples. Each tablet strength fixes the ratio, so one part cannot be changed without changing the other.
| Product | Second drug and its class | How often |
|---|---|---|
| Janumet | Sitagliptin, a DPP-4 inhibitor | Twice daily with meals |
| Synjardy / Synjardy XR | Empagliflozin, an SGLT2 inhibitor | Twice daily, or once daily for the XR tablet |
| Xigduo XR | Dapagliflozin, an SGLT2 inhibitor | Once daily in the morning with food |
Each label carries the warnings of both parts, such as metformin's lactic acidosis boxed warning and, for the SGLT2 combinations, diabetic ketoacidosis.
The Janumet label is not recommended at an eGFR of 30 to under 45, because those people need a lower sitagliptin dose than the fixed combination has. For people already on metformin, the Janumet starting dose adds sitagliptin 50 mg twice daily to the metformin dose they already take. Synjardy has a table of starting doses for people switching from the separate drugs.
One tablet means two drugs. Log the product and strength, such as 50 mg/1,000 mg, not just the brand, so anyone reading your history can see how much of each drug you take.
Read more on Dose Track: Janumet side effects · Synjardy side effects · Xigduo XR side effects · Metformin side effects