Janumet (Sitigliptin/metformin) Side Effects: For Type 2 Diabetics taking Janumet to lower their blood sugar, the most common side effects are diarrhea, nausea, stomach pain and vomiting. More serious side effects that you need to report to your physician are allergic reaction (swelling) or high or low blood sugar symptoms. Diabetics need to monitor their blood sugar levels with a glucose monitor regularly in order to prevent diabetes-related complications.
