Japanese pharmaceutical company Daiichi-Sankyo was recently the recipient of a dubious honor: its flagship product was selected as one of three prescription drugs with the most dangerous side effects.

That prescription is Benicar (olmesartan medomoxil), the blood pressure medication that has been associated with sprue-like enteropathy, a condition that mimics the symptoms of celiac disease. It came in #2 on Huffington Post’s list, just behind diabetic prescription drugs Avandia and Actos and ahead of antidepressent Paxil.

Benicar is classified as an “angiotensin II receptor antagonist” (ARB), meaning that it prevents certain protein molecules – known as receptors – from receiving biochemical signals. In this case, the signal is the hormone angiotensin, which causes blood vessels to constrict, leading to a rise in blood pressure (it is also known as a “vasoconstrictor”).

In addition to preventing the muscular wall of blood vessels from constricting, Benicar causes severe abdominal and chest pain. It can also result in breathing problems and vertigo and can lead to kidney failure. It has also been linked to nausea, acidification of the urine (hyperuricemia) and infection of the upper respiratory tract.

The most severe side effect is sprue-like enteropathy. For some time, physicians mistook this conditions with celiac disease. Patients exhibited the same symptoms, which include severe diarrhea, dehydration, vomiting and rapid weight loss. Sprue-like enteropathy causes a condition known as villous atrophy, in which small, finger-like protrusions along the intestinal walls, called villi, atrophy and no longer function. The job of villi is to furnish greater surface area for the intake of nutrients from food during the digestive process, taking in simple sugars and amino acids and passing them into the bloodstream. When the villi are no longer able to function, the result is malnutrition, starvation – and ultimately, death.

Although the symptoms are virtually identical, there is a major difference between sprue-like enteropathy and actual celiac disease. The difference is that the latter is caused by a reaction to gluten and can easily be treated with a change of diet. The only way to cure sprue-like enteropathy is to discontinue the use of Benicar. This was noted by a physician working at the Mayo Clinic in 2012, who turned the information over to the Food and Drug Administration. The FDA issued a warning the following July.

An interesting fact is that Benicar is not the only ARB on the market. However, while other ARBs contain only one ingredient, Benicar is a compound of different anti-hypertension substances. While the exact connection between Benicar and sprue-like enteropathy is not completely understood, research suggests that angiotensin that cannot bind to receptors remain in the bloodstream, causing an auto-immune reaction resulting in the celiac-like symptoms.

The first Benicar lawsuits were filed early in 2014. By October of 2015, there were more than 1100 cases pending against drugmaker Daiichi-Sankyo. Since being consolidated into multi-district litigation, the number of lawsuits have grown to nearly 1700. It is expected that additional lawsuits will be filed before the first cases are heard next year.

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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.