No, you should not substitute these medications without consulting your doctor. While both contain the same amount of metformin (1000 mg), they contain different primary active ingredients to control your blood sugar. Your original medication contains sitagliptin (50 mg), whereas the other contains teneligliptin (20 mg). Even though both sitagliptin and teneligliptin belong to the same class of drugs, they are different medicines with different dosing strengths. Switching between them requires your doctor's evaluation to ensure your blood sugar remains safely and effectively controlled. Please consult your prescriber before changing your medicine.