Medical Student Dayanand Medical College Rochester, New York, United States
Background: Thrombotic Thrombocytopenic Purpura (TTP) is a serious life-threatening disorder that results from autoantibodies against ADAMTS-13 protein leading to formation of microvascular platelet rich thrombi causing hemolytic anemia, thrombocytopenia, and end organ ischemia. Various anti-platelet drugs have been implicated in casing TTP but the degree of their association remains poorly studied.
Aims: To identify the association of anti-platelet drugs with TTP
Methods: We conducted a retrospective pharmacovigilance study using data from FDA Adverse Event Reporting System database to analyze the association of various antiplatelet drugs with TTP. Disproportionality signal analysis was done and reporting odds ratio (ROR) was calculated with a 95% confidence interval to identify positive signals.
Results: Among more than 2.7 million adverse events reported within the FAERS database, a total of 4111 events of TTP were found within which 843 cases were associated with various antiplatelet drugs. The distribution was 39.7 % in males and 47.3 % in females. 79.3 % were adults above 18 years of age, and 20.7 % patients had age not defined. Death was reported in 31.5 % cases. The top 5 drugs were Clopidogrel (512 cases, ROR 15.7, 95% CI 14.2-17.3), Ticlopidine (247 cases, ROR 25.1, 95% CI 22.0-28.6), Aspirin (95 cases, ROR 3.7, 95% CI 3.3-4.1), Prasugrel (31 cases, ROR 15.6, 95% CI 11.0-22.2), and Ticagrelor (22 cases, ROR 4.1, 95% CI 2.6-6.4).
Conclusion(s): This study helps to identify the various antiplatelet drugs commonly associated with TTP and compare the degree of their association. While most of the cases were found to be associated with Clopidogrel, a higher positive signal strength was found for Ticlopidine. Although ADP antagonists were found to be the most commonly associated drug class, Cangrelor did not have any reported events of TTP. This could be due to limited available data. More data is needed to identify safer anti-platelet agents.