Allergy to Plavix can be overcome: study
Allergies to Plavix, also know by its chemical name, Clopidogrel occur in about six percent of patients given the drug, vital for the prevention of life-threatening stent thrombosis after angioplasty and percutaneous coronary interventions. Researchers at Thomas Jefferson University found that a combination of steroids and antihistamines can successfully alleviate the allergic reaction and enable patients to remain on the drug. Until now, hypersensitivity required drug interruption, placing the patient at risk for restenosis or a major coronary event.
Thousands of people with heart disease and other cardiovascular conditions are prescribed Plavix, a blood thinner, by their physicians to prevent potential deadly blood clots. Because so many patients are on the drug, despite the relatively small number of reactions, it is a huge medical issue.
Led by Michael P. Savage, MD, director of the Cardiac Catheterization Laboratory at Jefferson, the study involved following 24 patients who developed Plavix allergies after getting stents placed to reopen clogged heart vessels. Jefferson doctors were able to keep 88 percent of them (21 of the 24) on Plavix without interruption after a short course of steroids and antihistamines.
"This is a very important study for many cardiac patients but especially those with stents," said Dr. Savage. "Every patient who receives a stent must take Plavix to help prevent stent thrombosis, which is clotting of the stent. This obviously poses major problems if the patient suffers an allergic reaction to the medication."
Discontinuing the drug can lead to a potentially fatal heart attack, Dr. Savage said. And patients must be on Plavix for at least a year after getting a stent placed. "That's a very long time to not be on a medication that may save your life."
Prior to this study at Jefferson, patients with allergic reactions to Plavix would need to be switched to an alternative medication, each with its own side effects, said John R. Cohn, MD, chief of Adult Allergy at Thomas Jefferson University Hospitals and a key contributor to the study.
"Rather than giving the secondary drug, we concentrated on suppressing the patient's allergic symptoms they were having to Plavix by administering low doses of steroids and antihistamines while continuing the drug," Cohn said. "What we found was that most of our patients became tolerant to Plavix, essentially becoming ‘desensitized’ to the drug, enabling them to continue treatment."
And, he added, the steroid and even antihistamine treatment could be discontinued after a short time.