Table 1. Mechanisms underlying drug-induced thrombocytopenia.
| Classification (Drugs) | Mechanism | Incidence |
|---|---|---|
| Hapten-dependent antibody (Penicillin, some cephalosporin antibiotics) | Hapten links covalently to membrane protein and induces drug-specific immune response | Very rare |
| Quinine-type drug (Quinine, sulfonamide antibiotics, nonsteroidal antiinflammatory drugs) | Drug induces antibody that binds to membrane protein in presence of soluble drug | 26 cases per 1 million users of quinine per week, probably fewer cases with other drugs |
| Fiban-type drug (Tirofiban, eptifibatide) | Drug reacts with glycoprotein αIIbβ3 to induce a conformational change by antibody (not yet confirmed) | 0.2–0.5% |
| Drug-specific antibody (Abciximab) | Antibody recognizes murine component of chimeric Fab fragment specific for platelet β3 | 0.5–1.0% after first exposure,10–14% after second exposure |
| Autoantibody (Gold salts, procainamide) | Drug induces antibody that reacts with autologous platelets in absence of drug | 1.0% with gold, very rare with procainamide and other drugs |
| Immune complex (Heparins) | Drug binds to platelet factor 4, producing immune complex for which antibody is specific; immune complex activates platelets through Fc receptors | 3–6% among patients treated with unfractionated heparin for 7 days, rare with low-molecular-weight heparin |
Table adapted from Aster and Bougie157[INSERT CORRECT LANGUAGE HERE IF TABLE IS USED]