Liraglutide (Victoza) has been approved by the Food and Drug Administration for the treatment of people with type 2 diabetes. The Novo Nordisk medication is a daily injection that can help lower blood glucose, but the FDA has specified that liraglutide only be used after diet, exercise, and older diabetes meds have failed to bring about the desired improvement.

The limitation is due to concerns that the new medication may cause thyroid cancer, a possibility raised by animal studies. Uncertainty about the risk in people held up liraglutide's approval for 10 months. (Victoza has been sold in Europe since 2009.) The FDA is requiring Novo Nordisk to monitor thyroid cancer rates in liraglutide users for years to come. The company will also monitor heart attacks and strokes in people taking the drug, an FDA requirement for all new diabetes meds.

Another possible side effect the FDA wants patients to be aware of is pancreatitis. In human studies, liraglutide users were more likely to get pancreatitis, a painful inflammation of the pancreas, than those on other diabetes medications. Information about the risk factors and symptoms of pancreatitis will be included with the medication.

Liraglutide is the first diabetes med to compete directly with exenatide (Byetta), a twice-daily meal-time injection that, since October, has been approved for initial or standalone therapy. Byetta is made by Amylin Pharmaceuticals and marketed with Eli Lilly & Co.

Both liraglutide and exenatide are incretin mimetics. These medications imitate naturally occurring hormones that spur post-meal insulin production by the pancreas and are associated with weight loss. Studies comparing the two meds head-to-head found that liraglutide lowered blood glucose more and had less severe side effects.