The FDA has given the green light for the first generic version of glucagon for injection, a drug that’s long been approved for treating severe hypoglycemia (very low blood sugar), which may occur in diabetes patients.

The agency’s approval of Amphastar Pharmaceuticals’ generic, which comes in a 1 mg injection emergency kit, also allows its use as a diagnostic aid for radiologic examinations of the stomach, duodenum, small bowel and colon. The drug has had FDA approval for more than two decades, but a generic version has not been granted the agency’s OK until now.

The agency said that Amphastar’s generic drug is a synthetic version of human glucagon, a hormone that prompts the liver to quickly increase blood sugar levels. It noted that the most common side effects of glucagon for injection are nausea and vomiting, temporarily increased heart rate, and redness and swelling at the injection site.