- Research Article
8
- 10.1161/circinterventions.108.832964
Frequency of Allergic or Hematologic Adverse Reactions to Ticlopidine Among Patients With Allergic or Hematologic Adverse Reactions to Clopidogrel
- Aug 01, 2009
- Circulation: Cardiovascular Interventions
- J O Lokhandwala + 7 more +7
Background-Clopidogrel and ticlopidine are structurally very similar.In patients with an allergic or hematologic adverse reaction to either one of these drugs, the likelihood that an allergic or hematologic adverse effect will develop to the other is unknown.It is also unknown whether a reaction to the second thienopyridine is likely to be life threatening.Methods and Results-Medical records from 2 academic institutions were reviewed to identify patients who had an allergic or hematologic adverse reaction to either of the 2 currently commercially available thienopyridines and who were subsequently prescribed the other thienopyridine.Patient demographics, details of the adverse reactions, and subsequent clinical course were reviewed.A total of 76 patients were identified with an allergic or hematologic adverse reaction to clopidogrel or ticlopidine who had also received the other thienopyridine.Fourteen (27%; 95% CI, 16 to 41) patients who had an allergic or hematologic adverse reactions to clopidogrel had a similar reaction to ticlopidine; none developed a life-threatening reaction.The most common reaction was a rash (93%).Conclusions-In patients with an allergic or hematologic adverse reaction to one thienopyridine, there seems to be an increased frequency of such reactions to the other thienopyridine.However, no patient had a life-threatening reaction after exposure to the alternative thienopyridine.(Circ Cardiovasc Intervent.2009;2:348-351.)Key Words: platelet aggregation inhibitors Ⅲ hemorrhage Ⅲ thienopyridine Ⅲ clopidogrel Ⅲ ticlopidine Ⅲ allergy Ⅲ cross-reactivityR ecent studies demonstrate that drug-eluting stents may pose a higher risk of late stent thrombosis than bare metal stents because of delayed healing. 1 This has lead to guidelines recommending dual antiplatelet therapy for at least 1 year after the placement of drug-eluting stents. 2 Premature cessation of dual antiplatelet therapy can be catastrophic. 3 Clinical Perspective on p 351Clopidogrel, a second-generation thienopyridine structurally similar to ticlopidine, was developed to be equally efficacious to ticlopidine but with fewer adverse effects. 4,5However, allergic or hematologic reactions occur in approximately 1% of patients taking clopidogrel and, when severe, require discontinuation. 6Substituting ticlopidine for clopidogrel is the most common practice in patients who develop a severe allergic or hematologic adverse reaction to clopidogrel.However, the frequency and severity of allergic cross-reactivity between the agents are not known.
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