Approved for medical use in 2006, Sitagliptin is a medication that comes as a tablet, and is used to treat high blood sugar levels caused by type 2 diabetes. It is worth noting that type 2 diabetes is an illness where the body does not make enough insulin, or the insulin that it makes does not work properly. This can cause high blood sugar levels (aka hyperglycaemia). Basically, Sitagliptin works by increasing the amount of incretin released by the intestine. Incretin is a hormone that raises insulin levels when blood sugar is high and decreases the amount of sugar made by the body. As for the side effects of this drug, they include headaches, swelling of the legs, and upper respiratory tract infections. Sitagliptin has other side effects that are more serious such as angioedema, low blood sugar, kidney problems, pancreatitis, and joint pain. Bear in mind that it is still unclear if using this medicine during pregnancy or breastfeeding is safe. You can take sitagliptin before or after a meal. However, you should take one tablet twice a day, after meals if you have been prescribed a combination tablet of sitagliptin with metformin