DPP-4 inhibitor

What it means

DPP-4 is the enzyme that breaks down natural GLP-1 and GIP within minutes. Blocking it lets your own incretin hormones last a bit longer, which helps the pancreas release insulin after meals.

The class includes sitagliptin (Januvia, approved in 2006), saxagliptin, linagliptin and alogliptin. They are once-daily pills for type 2 diabetes, often combined with metformin.

Because they only raise your own hormone levels modestly, their effect is much smaller than a GLP-1 receptor agonist. They are generally considered weight neutral and are not used for weight loss. They are also rarely combined with a GLP-1 medicine, since both work on the same pathway.

They rarely cause low blood sugar on their own. Labels mention rare risks such as pancreatitis, severe joint pain and, for some drugs in the class, heart failure.

Why it matters

If you switch from a DPP-4 inhibitor to a GLP-1 medicine, your prescriber will usually stop the DPP-4 pill rather than add to it.