OBJECTIVES: We hypothesized that a standardized outpatient clopidogrel desensitization protocol would be safe and effective. BACKGROUND: Adverse reactions to clopidogrel are not uncommon, and affected patients must switch to ticlopidine after drug-eluting stent placement, despite its more malignant side-effect profile, because of the risk of ischemic events associated with premature discontinuation of dual antiplatelet therapy. METHODS: Patients with suspected clopidogrel sensitivity were treated with escalating doses of clopidogrel administered orally in solution until either a clinically significant reaction occurred or the full 75-mg tablet of clopidogrel was tolerated. Desensitization was performed on an outpatient basis except in cases in which the subjects were inpatients at the time of enrollment. Follow-up was performed at 2 to 4 weeks and 6 months after treatment. Successful desensitization was defined as the ability to take clopidogrel 75 mg daily without a mucocutaneous, bronchial, or anaphylactic response. RESULTS: We enrolled 24 consecutive patients with suspected reactions to clopidogrel after DES implantation, 20 of whom were outpatients. During desensitization, allergic-type reactions occurred in 4 patients and angina occurred in 1 patient. Desensitization was acutely successful in all 24 patients, and by 6-month follow-up, 1 patient had persistent but improved pruritus controlled with oral antihistamines and 23 remained asymptomatic, with only 2 patients requiring repeat desensitization. CONCLUSIONS: Clopidogrel desensitization is safe and effective, induces a sustained remission, and could be advantageous in treating outpatients who are at-risk for premature discontinuation of dual antiplatelet therapy.
