It was a patient who first made the connection. He noticed that his bouts of nausea and vomiting disappeared when he was taken off his blood pressure pill during a hospital stay.

When he resumed the pill, the symptoms returned.

Now, his physician, Dr. Joseph Murray of the Mayo Clinic, has published a study linking the drug, olmesartan, to a potentially life-threatening gastrointestinal condition that mimics celiac disease.

Murray found that the pill, which is sold in the United States under the brand name Benicar, was associated with severe nausea, vomiting, diarrhea and weight loss in a group of 22 patients from 16 states, according to a report published online in Mayo Clinic Proceedings.

Some of the patients had been told -- apparently mistakenly -- that they had celiac disease, a severe intestinal disorder. A number were so sick that they were hospitalized repeatedly, he said, including one person who lost 125 pounds over the course of a year.

"Their symptoms substantially improved when they stopped the olmesartan," Murray said at a press briefing Thursday at Mayo.

Murray said this is the first study to find such a connection, and he stopped short of saying the drug caused the symptoms. He also said the condition appears quite rare.

"The vast majority of patients on this medication should not change," he said, but those with symptoms should talk to their doctors.

The drug's manufacturer, Daiichi Sankyo, issued a statement saying that it is reviewing the Mayo report, but that its own analysis in 2009 concluded "that a causal relationship between exposure to olmesartan and celiac disease is very unlikely." The company does, however, list several gastrointestinal symptoms, such as abdominal pain and nausea, among the drug's possible side effects.

One, then two, then 22

Murray, a specialist in celiac disease, said he began his investigation in 2009 after the first patient told him about his experience in the hospital, and asked whether the pill could be at fault.

The very next day, he said, another patient raised the same question -- and Murray learned they were both taking the same blood-pressure drug.

Eventually, Murray said, he studied 22 patients with similar stories. Although some had received a diagnosis of celiac disease, none responded to the typical treatments, such as a gluten-free diet. He also discovered that their blood tests did not match the diagnosis.

He said he started reporting the cases to the Food and Drug Administration in 2009. The FDA subsequently conducted its own investigation, he said, using a database of patients hospitalized with celiac disease, but did not find a "statistically significant" association with any blood pressure medication, including olmesartan.

However, Murray said he hoped the new findings would trigger further study. The report can be found at mayoclinicpro

Maura Lerner • 612-673-7384