One class of potentially dangerous diabetic prescriptions, SGLT-2 inhibitors, have been getting a great deal of attention these days. Meanwhile, a group of medications as gliptins have been flying under the radar. However, the risks associated with some drugs in this class are serious enough that medical experts recommend taking them off the market altogether.

The two most commonly-prescribed gliptin drugs today are Januvia (sitagliptin) and Onglyza (saxagliptin). Januvia, a product of Merck & Co., was the first drug of this class to gain FDA approval in 2006. Onglyza, approved in 2009, was developed jointly by Bristol-Myers Squibb and AstraZeneca. Today, it is marketed by the latter. Also known as DPP-4 inhibitors, these anti-hyperglycemic medications have been associated with severe histamine reactions (cold or hay fever symptoms), dangerously low blood sugar levels (especially when taken in combination with sulfonylurea drugs like Amaryl or DiaBeta), headaches, nausea, and skin rashes.

However, DPP-4 medications have also been linked to heart failure and pancreatic cancer.

“DPP-4” is an abbreviation for “dipeptidyl peptidase 4,” a biochemical substance that is involved with the production of glucagon. When glucagon is present, blood sugar levels rise. By suppressing the action of DPP-4, levels of glucagon go down and the pancreas produces more insulin, thus lowering the amount of sugar (glucose) in the blood.

In October 2013, the New England Journal of Medicine published a study that found a significant increase in the number of patients who took Onglyza being hospitalized for congestive heart failure. That study, funded by AstraZeneca and BMS, was technically a “success”. Only 27 percent of subjects experienced a cardiovascular event, which was below the 30 percent threshold. Nonetheless, the FDA expressed concerns and requested additional information from the drug manufacturers. Finally, a panel voted to have a warning label added to Onglyza packaging in April of 2015.

Two more studies, appearing in the journal Diabetes in 2009 and 2013, found an association between gliptin drugs and pancreatic cancer. Specifically, the first study found “worrisome changes” in the pancreatic tissue of lab rats who had been treated with gliptins, while the latter study noted pre-cancerous lesions on pancreases of organ donors who had taken similar medications. Januvia, in particular, has been a cause of action for multi-district litigation in which plaintiffs allege that gliptin drugs were the cause of their pancreatic cancers.

Current lawsuits against Onglyza manufacturer AstraZeneca allege that the company produced and sold a medication it knew to be dangerous, and failed to warn patients and doctors about the risk of congestive heart failure.

For many years, the first-line treatment for type-2 diabetes was metformin, a drug derived from French lilac (galega officinalis). Also known as “goat’s rue,” French lilac has a long history as a folk medicine for the treatment of what was once known as the “sweetwater sickness.” Since its introduction in the U.K. in 1958, metformin has been well-tolerated with virtually no serious side effects beyond occasional gastrointestinal upset and Vitamin B-12 deficiency.

The same cannot be said for many anti-hyperglycemic drugs introduced since the 1990s. Pioglitazone (Actos), DPP-4 inhibitors, and SGLT-2 inhibitors (Invokana, Jardiance, Farxiga) have all been associated with serious injuries, including cancer, kidney disease, and most recently gangrene.

Newer diabetic drugs are listed among the most dangerous prescription medications – and in many cases, may not even be necessary for patients willing to make major changes in lifestyle and diet.  If you are taking one of the newer diabetic prescription medications and have been experiencing unusual symptoms, it is important to discuss them with a medical professional, and if possible, get more than one opinion.

K.J. McElrath is a former history and social studies teacher who has long maintained a keen interest in legal and social issues. In addition to writing for The Ring of Fire, he is the author of two published novels: Tamanous Cooley, a darkly comic environmental twist on Dante's Inferno, and The Missionary's Wife, a story of the conflict between human nature and fundamentalist religious dogma. When not engaged in journalistic or literary pursuits, K.J. works as an entertainer and film composer.