Check Up: Exploring the mysteries of noncardiac chest pain

Millions of Americans suffer from recurring chest pain that is hard to explain and treat because it is not caused by their hearts.

They often undergo extensive testing and end up on drugs for acid reflux, depression, or even lung disease.

But only about 40 percent of noncardiac chest-pain patients respond to these drugs. And most still have painful symptoms, said Temple University gastroenterol-ogist Ron Schey.

Now, he may have found a novel way to treat some of them: dronabinol, a synthetic form of marijuana.

In a pilot study of 13 patients, the prescription drug, brand name Marinol, reduced the frequency of chest pain and improved pain tolerance more than a placebo.

While the study was too small to draw conclusions, the results warrant a larger trial - and point to yet another way that cannabis may be medically helpful.

Schey said the study, presented last month at the annual meeting of the American College of Gastroenterology, was deemed one of the "most newsworthy" due to the unmet need for therapy for noncardiac chest pain.

Dronabinol - which unlike marijuana, does not cause a "high" - is already used to treat nausea and vomiting in cancer and AIDS patients. Studies show it also helps some people with irritable bowel syndrome.

Schey thinks the drug may quiet down overactive nerves in the esophagus - the food pipe to the stomach - of patients with noncardiac chest pain. "Sensations that you or I would not even notice, they feel as excruciating pain because they are so hypersensitive," he said.

The hypothesis makes sense. The digestive tract is lined with cells that react to chemical signals from cannabinoids, the compounds found in cannabis. These cannabinoid receptors are involved in appetite, pain sensation, and memory.

Although dronabinol is known to activate two esophageal cannabinoid receptors, Schey was the first to test if that would translate to pain relief.

To do so, he recruited 13 people who had not responded to other therapies. Seven patients took dronabinol, and six took a placebo, twice a day for 28 days.

Changes in their symptoms were assessed at the start and finish using questionnaires, daily diaries, and an invasive test that Schey called "unpleasant."

Basically, a scope equipped with a balloon was threaded into the esophagus, then the balloon was gradually inflated with water. On a scale of one to four, patients rated their first sensation of pain and the maximum inflation they could tolerate.

The dronabinol group showed significantly more improvement than the placebo group in chest pain and anxiety, and some also got relief from swallowing discomfort.

Schey conducted the experiment while at the University of Iowa Hospitals and Clinic, and analyzed the data at Temple after joining its medical faculty this year.

He is now planning a study of 40 patients that would reduce the dronabinol dose to one or two tablets a week. While patients didn't report any adverse effects, a low dose may be sufficient due to the way the drug is absorbed and metabolized.

The timing of the research, he says, is good. Medical marijuana laws have been adopted by 23 states, including New Jersey, and a bill has been proposed in Pennsylvania.

Even though cannabis has been used therapeutically since ancient times, "we're still learning about it," he said.

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