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Benicar Side Effects

A common Benicar (olmesartan medoxomil) side effect is dizziness. Serious side effects include fetal toxicity in pregnant women and sprue-like enteropathy, a gastrointestinal condition similar to celiac disease that can lead to weight loss, malnutrition, severe diarrhea and hospitalization.

According to the U.S. Food and Drug Administration Adverse Event Reporting System, known as FAERS, brand names Benicar and Benicar HCT and their generics led to 16,845 adverse events from 2002 to September 30, 2019. Of those reports, 12,975 were serious, including 596 deaths.

FAERS reports are voluntary and the FDA does not verify if the drugs actually caused these side effects. The most reported adverse events include sprue-like enteropathy, gastroesophageal reflux disease, diarrhea, weight loss and acute kidney injury.

The drug’s label has a black box warning for fetal toxicity. Pregnant women should not take the drug. Women should stop taking the drug if they find out they are pregnant.

Benicar can also cause some less severe but still serious conditions that require continued monitoring. Patients with dehydration and low sodium levels may experience low blood pressure after starting the drug. People with severe congestive heart failure or who are otherwise susceptible may suffer impaired kidney function. There’s also a risk of electrolyte imbalances, including elevated levels of potassium in the blood serum. Facial swelling (or edema) occurred in 5 patients out of 3825 patients in clinical studies.

Benicar’s package insert says dizziness was the most common side effect in clinical trials. It occurred in about 3 percent of trial participants. Benicar HCT’s most common side effects include nausea, hyperuricemia, dizziness and upper respiratory infection. These occurred in 2 percent or more of trial participants.

According to the insert, there were several post-marketing reports of adverse reactions linked to Benicar. But researchers cannot say how often these occur or if the drug caused them.

Those reactions include:
  • Acute renal failure
  • Alopecia (hair loss)
  • Anaphylactic (serious allergic) reactions
  • Angioedema (swelling under the skin)
  • Asthenia (decreased muscle strength)
  • Hyperkalemia (high levels of potassium)
  • Increased blood creatinine levels
  • Pruritus (itching of the skin)
  • Rhabdomyolysis (muscle tissue breakdown)
  • Sprue-like enteropathy (gastrointestinal problems)
  • Urticaria (rash)
  • Vomiting

Fetal Toxicity

Research has linked olmesartan, the active ingredient in Benicar, to fetal toxicity. The effects on the fetus typically happen when women take the drug during the second and third trimester of pregnancy.

The package insert says use of the drug during the second and third trimester of pregnancy reduces fetal function and increases fetal and neonatal disease rates and death.

The drug can also harm amniotic fluid, which can be associated with underdeveloped fetal lungs and deformed bones, including the skull. Other fetal complications include urine retention and low blood pressure.

Women who become pregnant are advised to discontinue the medication as soon as possible in consultation with their doctors. If a pregnant woman must continue taking the drug, she should be advised of the potential risk to her fetus.

The manufacturer says it doesn’t know if the drug is excreted in human milk, but it has been found in low concentrations in the milk of lactating rats. Because of the potential for adverse effects on infants, nursing mothers should consult with their doctors about whether to continue taking the medication. Children younger than 1 year should not ingest the drug because it may alter normal kidney development.

Severe Gastrointestinal Side Effects

In 2013, the U.S. Food and Drug Administration issued a safety announcement warning consumers that Benicar, as well as similar drugs such as Benicar HCT, Azor, Tribenzor and generic versions, can cause severe intestinal complications collectively known as sprue-like enteropathy.

Most often, when patients take prescription medications that cause diarrhea the side effect occurs without permanent damage to the intestines. But sometimes severe diarrhea can cause substantial weight loss, malabsorption and permanent damage to the intestines. These symptoms are typically associated with celiac disease due to gluten exposure. However, drug-induced enteropathy can occur independent of gluten intake and does not go away with a gluten-free diet.

The FDA evaluated reports in published literature as well as databases including the FDA’s Adverse Event Reporting System (FAERS), the Centers for Medicare and Medicaid Services (CMS) database and a pilot version of a national medical product monitoring system called Sentinel Initiative.

“FDA’s evaluation found clear evidence of an association between olmesartan and sprue-like enteropathy,” the agency said.

Sprue-like Enteropathy Warning
Symptoms of sprue-like enteropathy can develop months to years after taking Benicar or other medications containing olmesartan.
Source: U.S. Food and Drug Administration

The gastrointestinal disorder usually resolved once patients stopped taking the drugs, according to the FDA. In severe cases, patients ended up in the hospital. Some suffered from villous atrophy, which occurs when microscopic, finger-like projections that help absorb nutrients erode away, causing the walls of the small intestine to essentially become a flat surface. This can cause serious nutritional deficiencies. This condition also resolved in most patients when Benicar was discontinued.

Based on its findings, the FDA approved changes to the drugs’ labels to include sprue-like enteropathy. More than 2,000 people who used Benicar and developed intestinal side effects filed lawsuits.

In November 2017, the consumer advocacy group Public Citizen petitioned the FDA to remove Benicar from the market and ban the sale of the drug and several generic versions because of “overwhelming evidence” that the medications cause sprue-like enteropathy. The group noted that the risk of the life-threatening gastrointestinal disorder is “far greater” with olmesartan than with other medications in the same class of drugs.

The FDA responded to the petition in October 2019. The agency denied the petition to withdraw Benicar from the market as no new evidence regarding the drug’s safety was reported.

According to the FDA response, the finding from the studies cited in the petition were adequately addressed in the drug labeling change in 2013. With respect to the risk of the disorder being greater than other medications in its class, the FDA stated that education of the patient and healthcare provider to monitor for symptoms of this potential adverse event addresses the concern.

Furthermore, the FDA’s response stated that withdrawal of this agent from the market would adversely impact a large number of patients who have adequate blood pressure control without adverse events with Benicar and Benicar-containing medications. The FDA concluded with the statement that the safety of the drug would continue to be under surveillance.

Causes and Symptoms of Olmesartan-Induced Sprue-Like Enteropathy

Drug-induced diarrhea can occur for any number of reasons. Its cause is uncertain in patients taking Benicar. However, the FDA wrote that research suggests olmesartan-induced sprue-like enteropathy may be a delayed hypersensitivity or immune response to the medication because it develops months to years after starting treatment.

Patients experiencing olmesartan-induced sprue-like enteropathy exhibit signs and symptoms similar to individuals suffering from celiac disease.

Signs and symptoms of sprue-like enteropathy
Signs and symptoms of sprue-like enteropathy
  1. Severe, chronic diarrhea
  2. Substantial weight loss
  3. Malabsorption
  4. Abdominal pain
  5. Fatigue
  6. Bloating
  7. Nausea
  8. Vomiting
  9. Anemia

The FDA advises patients to contact their physicians if they develop severe, chronic diarrhea or significant weight loss while taking Benicar, even if it takes months or years for the symptoms to appear. If a doctor cannot identify causes other than the medication, then he or she may recommend discontinuing the drug and replacing it with another blood pressure treatment.

Benicar Pills
Benicar Side Effects
  1. Black Box Warning fetal toxicity (potential kidney failure, bone deformity, low blood pressure)
  2. FDA Safety Announcement intestinal problems (sprue-like enteropathy)
  3. Common Side Effects dizziness (seen in about 3 percent of clinical trial participants)

Please seek the advice of a medical professional before making health care decisions.

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Kristin Compton
Written By Kristin Compton Writer

Kristin Compton's background is in legal studies. She worked as a paralegal before joining Drugwatch as a writer and researcher. She was also a member of the National Association of Legal Assistants. A mother and longtime patient, she has firsthand experience of the harmful effects prescription drugs can have on women and their children. Some of her qualifications include:

  • Bachelor of Arts in Legal Studies | Pre-Law from University of West Florida
  • Past employment with The Health Law Firm and Kerrigan, Estess, Rankin, McLeod & Thompson LLC
  • Personal experience battling severe food allergies, asthma and high-risk pregnancies
Edited By
Emily Miller
Emily Miller Managing Editor
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10 Cited Research Articles writers follow rigorous sourcing guidelines and cite only trustworthy sources of information, including peer-reviewed journals, court records, academic organizations, highly regarded nonprofit organizations, government reports and interviews with qualified experts. Review our editorial policy to learn more about our process for producing accurate, current and balanced content.

  1. Public Citizen. (2017, November 15). Petition to the FDA to Ban Olmesartan-Containing Hypertension Medications. Retrieved from
  2. FDA. (2019, October). Benicar package insert. Retrieved from
  3. Anderson, J. (2020, January 12). Conditions That Cause Villous Atrophy. Retrieved from
  4. U.S. Food and Drug Administration. (2013, July 3). FDA Drug Safety Communication: FDA approves label changes to include intestinal problems (sprue-like enteropathy) linked to blood pressure medicine olmesartan medoxomil. Retrieved from
  5. Rubio-Tapia A, Herman ML, Ludvigsson JF, et al. (2012 August). Severe Spruelike Enteropathy Associated With Olmesartan. Retrieved from
  6. Health Information Center. (2015, July). Kidney Dysplasia. Retrieved from
  7. U.S. National Library of Medicine. (2017, October 2). Drug Record: Olmesartan. Retrieved from
  8. Tran, T. and Li, H. (2014, January). Olmesartan and Drug-Induced Enteropathy. Retrieved from
  9. U.S. Food and Drug Administration. (n.d.). FDA Adverse Event Reporting System. Retrieved from
  10. U.S. Food and Drug Administration. (2019, October 9). Response Letter to Public Citizen Petition to the FDA to Ban Olmesartan-Containing Hypertension Medications. Retrieved from
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