Acute Reactions to Gadolinium-Based Contrast Agents Are Rare, Study Finds
Last Updated: 2010-01-22 15:29:48 -0400 (Reuters Health)
NEW YORK (Reuters Health) - The rate of acute allergic reactions to gadolinium-based contrast agents is low, according to a retrospective study from the Massachusetts General Hospital.
Of 32,659 patients given either gadopentetate dimeglumine (Magnevist) or gadobenate dimeglumine (MultiHance) for enhanced magnetic resonance imaging, 50 patients experienced 51 acute adverse reactions (0.16%). Stratified by agent, the rates of adverse reactions were 0.14% with gadopentetate dimeglumine and 0.28% with gadobenate dimeglumine. The study was not designed to compare adverse events between the two, however.
One patient had mild reactions on two separate occasions, even though he was premedicated with steroids and diphenhydramine before the second exam.
Most reactions were mild, such as hives, rashes and nausea. Six patients had moderate adverse reactions, including cough, bronchospasm, dyspnea, or diffuse erythema. Two had severe reactions: seizure in one, and cardiopulmonary arrest in the other. The severe reactions occurred with gadobenate dimeglumine. All patients recovered, however.
The report, published in the February issue of the American Journal of Roentgenology by radiologist Dr. Hani Abujudeh and colleagues, is generally in line with earlier studies. The authors do point out that the 0.28% rate of reactions to gadobenate dimeglumine is lower than what other large studies have reported.
Gadolinium-based contrast agents came under increased scrutiny in 2006, when Danish and German nephrologists reported an association with nephrogenic systemic fibrosis (NSF), a debilitating and sometimes fatal condition. Contrast-related NSF is a concern only in patients with underlying renal impairment, and particularly in those with end-stage renal disease. The risk in these patients was as high as 4.6% in one report, according to the researchers, who published findings related to NSF in December last year. In their new study, they focused only on acute reactions.
"For many years, we considered gadolinium-based contrast agents to be safe," Dr. Abujudeh told Reuters Health. "The only decision that we had to make was whether the patient needed them or not."
Now, before deciding to use a specific contrast agent, he considers both delayed reactions such as NSF and acute allergic reactions.
"I think anybody using (gadolinium-based contrast agents) has to be constantly reminded that patients can have adverse reactions from these drugs," said Dr. Jeffrey Weinreb, director of medical imaging at Yale University, who was not involved in the study. He noted that 36 million doses of the contrast agents were used in 2008.
After they were linked to NSF, he added, it was easy to forget that acute reactions are really much more common than delayed reactions. Patients with a history of allergies might require premedication with oral steroids.
Overall, though, the incidence of severe adverse reactions to this type of contrast agent is extremely low, according to Dr. Weinreb. Compared with iodinated contrast agents, which are often used in X-ray imaging, the present rates are about an order of magnitude lower, he said.
Dr. Abujudeh receives grant support from Bracco Diagnostics, the manufacturer of MultiHance.
Am J Roentgenol 2010;194:430-434.
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