Taste of oral contrast agent affects patient compliance, radiology experience

Taste matters when it comes to oral contrast agents, and may affect patient compliance, according to a new study published in the American Journal of Roentgenology. Patients preferred diluted oral contrast agent iohexol (GE Healthcare’s Omnipaque) to diluted diatrizoate sodium (Mallinckrodt’s Gastroview) when undergoing abdominopelvic CT scanning.

The researchers found 81% of patients in their 300-person study preferred iohexol. Neither agent had flavoring added.

“The better taste with iohexol should improve patient compliance with drinking the necessary amount of contrast medium and improve overall satisfaction with the radiology experience,” said Dr. Michelle McNamara, a diagnostic radiologist and assistant professor at the University of Alabama-Birmingham, and lead author of the study.

In the prospective double-blinded study, patients were randomized to receive either iohexol or diatrizoate sodium, and graded the taste of the agents using a five-point scale.

As a secondary objective of the study, CT images were graded for bowel opacification by two blinded abdominal radiologists. The researchers found no difference in bowel opacification between the two agents.

“Receiving an oral contrast agent is often the least pleasant part of the radiology experience for a patient,” McNamara said. “Patients often complain of an unpleasant taste, and many experience gastrointestinal side effects such as nausea and vomiting. This may result in decreased satisfaction with the procedure and poor compliance with oral contrast dosing.”

The results of this study are positive but many radiology departments now spike their oral contrast agent with a flavored drink to improve the taste anyway, according to Dr. Jay Heiken, a professor of radiology and an abdominal imaging expert at Washington University in St. Louis.

“Some radiology departments, including my own, no longer routinely administer an oral contrast agent for body CT, making the comparison a moot point in those departments,” he said.

However, very ill patients might benefit from iohexol’s more acceptable flavor as they often have difficulty drinking oral contrast because of its taste, he said.