FRIDAY, May 12 (HealthDay News) -- A new method developed by U.S. researchers can help patients overcome an allergy to a common anti-clotting drug, clopidogrel (brand name Plavix).

Doctors often prescribe the drug to help prevent new blockages inside coronary stents, but about two out of every 100 patients who receive clopidogrel develop an allergic reaction marked by rash, itching, hives, or swelling of the tongue and airway. Some patients develop an anaphylactic reaction and go into shock.

"Allergic reactions can be quite frightening to patients and physicians, and can lead to discontinuation of the medication. We showed we could successfully and safely desensitize patients who had just recently had a drug-eluting stent placed. That's a critical population to manage," Dr. Nicolas E. Walker, a cardiology fellow at the University of Iowa in Iowa City, said in a prepared statement.

The desensitization protocol was used on eight patients. While being monitored in the cardiac ICU, the patients were first given a small dose of clopidogrel mixed into a drinkable solution. Every 15 minutes over the next few hours, the patients received an additional, higher dose of the drug. This continued until they were able to tolerate the target dose of 75 milligrams of clopidogrel. In total, the patients received nine doses totaling 150 milligrams of the drug.

Antihistamines and other anti-allergy medicines were used to treat patients who developed allergy symptoms during the desensitization process. All eight patients completed the process and were able to safely take a daily 75 milligram dose of clopidogrel at home without suffering allergic reactions.

Patients who suffer the most severe reaction -- anaphylactic shock -- to clopidogrel were not included in this study.

The findings were presented Thursday at a meeting of the Society for Cardiovascular Angiography and Interventions in Chicago.

SOURCE: Society for Cardiovascular Angiography and Interventions, news release, May 11, 2006