Ticagrelor Use in a Patient With a Documented Clopidogrel Hypersensitivity

OBJECTIVE: To report the use of ticagrelor in a patient with a documented hypersensitivity reaction to clopidogrel. CASE SUMMARY: A 64-year-old woman presented with non-ST-segment elevation myocardial infarction (NSTEMI) with a history significant for a hypersensitivity reaction to clopidogrel and was medically managed. Based on the patient's past medical history and current evidence available, the determination was made to use ticagrelor in this patient. Ticagrelor was administered without reaction during the hospital stay and on assessment at 2 and 4 weeks postdischarge. DISCUSSION: Hypersensitivity occurs in approximately 1% of patients receiving clopidogrel. Although the risk of hypersensitivity reaction to clopidogrel is low, evidence to support alternative antiplatelets in this setting is relatively limited. Prasugrel has a similar structure to clopidogrel and, therefore, may cross-react. Furthermore, prasugrel is not recommended in the medical management of NSTEMI. Ticagrelor is a newer P2Y12 inhibitor that contains a cyclopentyltriazolopyrimidine structure. Because of the difference in structure, a lower theoretical risk of cross-reactivity with the thienopyridines would be anticipated. However, there are no reports to date that investigate the use of this agent in patients with a documented thienopyridine allergy. CONCLUSIONS: The current case report describes the use of ticagrelor in a patient with documented hypersensitivity to clopidogrel. In this patient, ticagrelor was well tolerated during hospital admission and at 2 and 4 weeks postdischarge following administration.