DPP-4 diabetes drugs might cause “severe and disabling” joint pain, according to a new warning issued by the FDA.

Research by the agency’s drug safety team has turned up cases of severe joint pain in patients using DPP-4 inhibitors to control their blood sugar. In its drug safety communication, the FDA said the symptoms sometimes were immediate, but at other times surfaced years after a patient started taking one of the drugs.

After the drugs were discontinued, the patients’ symptoms stopped, generally in less than 30 days. Some patients saw the pain return after they restarted the same product or switched to a different DPP-4 drug.

The FDA’s joint-pain warning was added to the official labeling on the entire DPP-4 class. The most popular DPP-4 meds are Merck & Co.’s Januvia products and two Januvia-plus-metformin products that are sold under the Janumet brand. The class also includes AstraZeneca’s Onglyza (saxagliptin) and its metformin combo Kombiglyze; Eli Lilly and Boehringer Ingelheim’s Tradjenta (linagliptin) and related combos Glyxambi and Jentadueto; and the newest entry, Takeda's Nesina (alogliptin), and two combo pills, Kazano and Oseni.

The FDA has added warnings to the meds in the past. The entire DPP-4 class already carries cautionary language about the risk of pancreatitis and allergic reactions, in addition to hypoglycemia when used in combination with other diabetes meds.