Barium sulfate is opaque to X-rays, which means that X-rays don't pass through it. Doctors use barium sulfate to provide contrast in radiographic examinations of the gastrointestinal tract. Body structures containing barium sulfate stand out clearly on the X-ray film. Patients take barium sulfate orally when having an exam of the esophagus, stomach or small intestine. It is given rectally to examine the distal small intestine and colon. Although allergic reactions to barium sulfate are rare, they do occur, so understanding the risks involved will help you make a better decision about having this kind of examination.

Ingredients

Barium sulfate itself usually is not absorbed in the intestinal tract, but some of the additives to the barium sulfate solution are absorbed. Additives include ingredients used to suspend the barium sulfate in liquid, to improve the flavor and to make the texture more palatable. For instance, HD 85 is a raspberry-flavored barium sulfate mixture that contains suspending and dispersing agents, simethicone, potassium sorbate, sodium citrate, citric acid, artificial sweetener, other flavorings and water.

Allergic Reactions

The "New England Journal of Medicine" in October 1997 reported the case of a 63-year-old woman who had a severe allergic reaction after an upper gastrointestinal examination with barium sulfate. Tests revealed that she was allergic to carboxymethylcellulose sodium, an ingredient in the barium sulfate used in the examination. According to the "Encyclopedia of Diagnostic Imaging," allergic reactions to barium sulfate are rare, occurring in about one patient out of 750,000. One of the ingredients implicated in allergic reactions is glucagon, which is used to reduce discomfort during barium sulfate examinations. The authors of the encyclopedia suggest that some allergic reactions may be due to the latex in medical gloves or enema balloons used in the examinations.

Risk-Benefit

You have a greater risk of an allergic reaction to the ingredients in barium sulfate if you have a history of asthma or allergies, such as hay fever, or you have had a reaction to barium sulfate or any of the other ingredients in the barium sulfate preparation. It's impossible to predict which patients will have an allergic reaction to a barium sulfate preparation, so doctors who administer these tests are prepared to deal with an allergic reaction.

Symptoms

If you experience hives, itching, swelling of your throat or difficulty breathing or swallowing, rapid heart beat, agitation or confusion after a gastrointestinal exam with barium sulfate, you may be suffering an allergic reaction to something in the preparation. Tell your doctor immediately or go to the emergency room, as this can be a life-threatening condition.