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Benicar FDA Warnings and Medical Studies

Benicar FDA WarningsSince the FDA’s 2002 approval of Benicar (olmesartan medoxomil) as a treatment for hypertension, medical studies have continued to reveal serious, sometimes life-threatening side effects of the drug. The agency has responded by issuing a number of safety announcements and requiring significant changes to the Benicar label.

Gastrointestinal side effects of Benicar

Benicar manufacturer Daiichi Sanyo originally informed the FDA that patients in clinical trials of the drug reported dizziness as its principal side effect. The manufacturer told the agency that Benicar patients were approximately three times as likely to report dizziness as were patients taking the placebo – 3% vs. 1% overall.

But dizziness quickly was replaced by far more serious complications among Benicar users. By 2007, diarrhea, nausea, vomiting and similar symptoms were being reported by patients taking Benicar. These are often signs of Celiac disease, which damages the lining of the small intestine and prevents the body from absorbing important nutrients from food; it is often associated with an allergy to gluten found in wheat, barley, rye, and other grains.

When the FDA analyzed the reports, however, it found no definitive evidence of Celiac disease among patients taking Benicar.

In 2010, researchers at the Mayo Clinic began to suspect a possible association between intestinal symptoms and olmesartan use. The researchers reported that “two consecutive patients referred to our institution for evaluation of presumed refractory Celiac disease reported unexplained clinical improvement during hospitalization but prompt relapse following hospital discharge. They asked if the disease course could have been due to their hypertensive medications, which were withheld on hospitalization because of hypotension.”

The physicians had already been studying patients with a particular type of gastrointestinal disorder known as “collagenous sprue.” When they learned that one-third of the patients who had recently been diagnosed with the condition had also been taking Benicar, the researchers began to look even more closely at the possible association between use of the drug and the gastrointestinal (GI) symptoms. As a result, the doctors examined records of Mayo Clinic patients going back to 2008, and continued their study through 2011.

In 2012, the researchers reported to the FDA that 22 patients taking Benicar had been diagnosed with serious diarrhea, substantial weight loss, and poor absorption of nutrients. The patients did not have Celiac disease despite the similarity of symptoms. The patients were instead diagnosed with a condition called “sprue-like enteropathy.”

The Mayo Clinic doctors advised the FDA that:

  • Patients lost as much as 125 lbs., with a median reduction of 40 lbs.
  • Hospitalization was needed for two out of three patients
  • Symptoms in every patient improved significantly after cessation of Benicar use
  • Patients regained 27 lbs. on average
  • Among patients whose small intestines were later biopsied, all 18 showed substantial improvements

FDA response

Thereafter, the FDA reviewed the documentation it had received concerning Serious Adverse Events associated with Benicar use. In 23 cases, patients taking Benicar had experienced significant weight loss and very serious diarrhea. Like the patients in the Mayo Clinic study, the patients reporting to the FDA stated that their symptoms either resolved entirely or became significantly less serious once they ceased using Benicar.

As a result, the FDA required Benicar’s manufacturer to update its labeling in July 2013. Patients were now warned that Benicar had caused sprue-like enteropathy, which the FDA defined as severe, chronic diarrhea with substantial weight loss. After describing the results of the Mayo Clinic study and the reports the FDA itself had received, the FDA warned: “If patients taking olmesartan develop these symptoms and no other cause is found, the drug should be discontinued, and therapy with another antihypertensive started. Discontinuation of olmesartan has resulted in clinical improvement of sprue-like enteropathy symptoms in all patients.”

Other medical studies and FDA actions

In addition to the studies finding gastrointestinal side effects from Benicar, researchers explored a variety of other complications for possible association with use of the drug.

In June 2010, the FDA reported on two ongoing clinical trials regarding the effectiveness of Benicar in reducing kidney disease among patients with Type 2 diabetes. Patients in the trials who were taking Benicar had significantly higher death rates from cardiovascular events (heart attacks, strokes) than did those taking the placebo.

The FDA issued a Drug Safety Communication announcing an ongoing safety review of this issue, acknowledging that, although the trials found death rates among Benicar patients to be 5 and 3.33 times as high as among the placebo patients, the agency “has not concluded that Benicar increases the risk of death.”

In April 2011, the FDA issued a follow-up communication concluding that “the benefits of Benicar continue to outweigh its potential risks when used for the treatment of patients with high blood pressure according to the drug label.” The agency did not opine further on any association between Benicar use and an increased risk of heart attack or stroke.

Instead, the FDA announced, “Daiichi Sankyo, the makers of Benicar, have agreed to work with the FDA to perform additional studies, as well as conduct additional analyses of completed clinical studies, to obtain more complete information about the cardiovascular risks or benefits of Benicar in various clinical settings. FDA will update the public when new information is available.”

A number of additional medical studies have caused the FDA to require new warnings on the Benicar label.

Among these new Benicar side effects and their associated warnings were:

  • Acute myopia, eye pain and possible permanent vision loss within hours to weeks of beginning Benicar treatment (May 2011)
  • Deterioration of renal (kidney) function and possible renal failure in certain patients also taking non-steroidal anti-inflammatory agents (NSAIDs such as ibuprofen) (May 2011)
  • Interference with normal kidney development in children under one year of age; Benicar not to be used to treat hypertension in patients before their first birthday (February 2012)
  • Benicar not shown to be effective in children under six years of age (February 2012)
  • Risk of fetal skull hypoplasia, hypotension, renal failure and death in second and third trimesters; FDA issued Black Box warning (used to emphasize most dangerous risks to human life and health) (March 2012)

Patients, families, and health care providers will no doubt continue to monitor the FDA’s ongoing review of medical studies regarding Benicar side effects.

  1. FDA, “Benicar Label,” February 12, 2013,

  2. FDA, “FDA Drug Safety Communication: FDA approves label changes to include intestinal problems (sprue-like enteropathy) linked to blood pressure medicine olmesartan medoxomil,” July 3, 2013

  3. Rubio-Tapia, A, et al., “Severe spruelike enteropathy associated with olmesartan.” Mayo Clinic Proc. August 2012

  4. Pharmacovigilance Forum, “Olmesartan and Drug-Induced Enteropathy,” January 2014,

  5. FDA, “FDA Drug Safety Communication: Ongoing safety review of Benicar (olmesartan) and cardiovascular events,” June 11, 2010

  6. FDA, “FDA Drug Safety Communication: Safety Review Update of Benicar (olmesartan) and cardiovascular events” April 14, 2011