[Clopidogrel and thrombopenia. A case report]

Severe isolated thrombocytopenia after clopidogrel and pentoxifylline therapy: a case report

Introduction

Clopidogrel is frequently associated with thrombotic thrombocytopenic purpura, however this drug is rarely related to severe isolated thrombocytopenia. Pentoxifylline has previously been associated with thrombocytopenia only once. To the best of our knowledge, this is the first report of severe isolated thrombocytopenia after therapy with both clopidogrel and pentoxyfilline.

Case presentation

We report the case of a 79-year-old Caucasian man who presented to our facility with intermittent claudication. He had obliterative arterial disease and started therapy with clopidogrel and pentoxifylline. His basal platelet count was 194 × 10⁹ cells/L. At three days after the start of treatment, our patient had lower limb petechia and stopped taking clopidogrel and pentoxifylline. His platelet count lowered to 4 × 10⁹ cells/L and our patient was admitted to hospital. Our patient had purpura with no other hemorrhages or splenomegaly. Results of a blood smear were normal, and a bone marrow study showed dysmegakaryopoiesis. Antiplatelet antibody test results were negative, as were all viral serology tests. Imaging study results were normal. Our patient was given immunoglobulin but there was no sustained platelet increase, so corticotherapy was started as the next treatment step. At five months after clopidogrel and pentoxifylline were discontinued, his platelet count continued increasing even after prednisolone was tapered.

Conclusions

Severe isolated thrombocytopenia may appear as a side effect when using clopidogrel and pentoxifylline. These drugs are widely used by general physicians, internists, cardiologists and vascular surgeons. We hope this report will raise awareness of the need to monitor the platelet count in patients taking these drugs.

Profound thrombocytopenia induced by clopidogrel with a prior history of long-term safe administration

Clopidogrel has shown an excellent safety, tolerability and efficacy ever since its marketing. However, here we report a rare case with profound thrombocytopenia following clopidogrel administration previously safely exposed to this same drug. This reminds us that thrombocytopenia might be induced by clopidogrel even with a prior, safe history of long-term administration.

Antiplatelet drug induced isolated profound thrombocytopenia in interventional cardiology: a review based on individual case reports

A combination antithrombotic and antiplatelet therapy with clopidogrel, aspirin, glycoprotein IIb/IIIa receptor inhibitors and heparins is routinely used as adjunct therapy in patients undergoing percutaneous coronary intervention (PCI). As all substances inhibit platelet function, bleeding and thrombocytopenia may occur. We report on three patients who developed isolated profound thrombocytopenia (platelet count of < 20,000/mm(3)) within 24 h after initiation of combination antiplatelet and antithrombotic therapy during a 1 year observation period in 443 consecutive patients undergoing PCI and stent implantation. The data from our cardiology unit revealed an incidence of an isolated profound thrombocytopenia in 0.7% of all patients on combination antithrombotic therapy and in 1.5% of patients with GPIIb/IIIa-blockers. In all three cases with isolated profound thrombocytopenia GPIIb/IIIa-blockers were found to be the causative agents. Negative results of HIT-assays excluded heparin induced thrombocytopenia type II. Despite the extremely low platelet count no severe bleeding was observed and in all cases platelet counts normalized within 3-4 days without specific interventions except discontinuation of the responsible agent. These findings are discussed in conjunct with an overview of the recent literature.