Frequency of Allergic or Hematologic Adverse Reactions to Ticlopidine Among Patients With Allergic or Hematologic Adverse Reactions to Clopidogrel

Abstract

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. 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. 4,5 However, allergic or hematologic reactions occur in approximately 1% of patients taking clopidogrel and, when severe, require discontinuation. 6 Substituting 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. Methods PatientsThe electronic health records from the Geisinger Clinic (Danville, Pa) and the Mayo Clinic (Rochester, Minn) were reviewed to identify patients older than 18 years with an allergy to a thienopyridine in their medical record between January 1995 and June 2007. These patients were sorted into 3 groups based on whether their allergy was either to 1 of the 2 currently available thienopyridines or to both. Of the patients with an allergy to only one thienopyridine, only those who had also received the other thienopyridine, as determined by a query of their electronic medication lists, were selected for inclusion in this analysis. These medication lists include all medications prescribed by all physicians throughout the Geisinger or Mayo systems and are reconciled at each clinic visit with those the patient is actually taking. For each patient thus identified, medical records were reviewed to assess adverse reaction details and subsequent clinical course. Only patients whose adverse reactions met t...

Management Strategies for Clopidogrel Hypersensitivity

“…One study analyzed 76 patients with confirmed allergy to either clopidogrel, ticlopidine, or both [44]. Only patients who had received both clopidogrel and ticlopidine were included in the analysis.…”

Allergic reaction to prasugrel and cross-reactivity with clopidogrel

“…Alas, ticlopidine commonly causes major hematologic adverse events. When administering ticlopidine to patients with copidogrel allergy 27% of the patients have a similar reaction to ticlopidine [2]. As for prasugrel, this is the first report of cross-reactivity with clopidogrel.…”

“…Both drugs are commonly used in cardiovascular patients, mainly those undergoing percutaneous coronary interventions (PCI) and implantation of intra-coronary stents.Allergic or hematologic adverse reactions to clopidogrel are well described and occur in about 1% of patients, of which 93% present with a maculopapular rash that commonly leads to drug discontinuation [1,2]. Allergic reaction generally occurs by 6 days after exposure to clopidogrel, although it can appear within 24 h [3].…”

“…While there have been several published cases of thienopyridine-associated rash [4], and cross-reactivity between orally administered clopidogrel and ticlopidine [2,4]. Prasugrel is structurally similar to clopidogrel, one might surmise that cross-reactivity may also be seen.…”

Circulation: Cardiovascular Interventions Editors' Picks

“…While limited data regarding hematologic cross reactivity are provided in this analysis, the data suggest that switching thienopyridines in patients presenting with an allergic response to prior thienopyroidine therapy will not be a successful strategy in a significant minority of these patients. 6 Increased Risk of Bleeding in Patients on Clopidogrel Therapy After Drug-Eluting Stents Implantation: Insights From the HMO Research Network-Stent Registry (HMORN-Stent) Summary: Recent studies have suggested that prolonged dual antiplatelet therapy (Ͼ6 months) after drug-eluting stent placement may be associated with reduced risk of myocardial infarction and death. As a result, many clinicians have extended treatment with clopidogrel to exceed 12 months and even 18 months.…”