Platelet counts in depressed patients treated with amitriptyline or paroxetine

Abstract Objective. – To assess whether therapy with two widely used antidepressants influences platelet counts. Subjects and methods. – In 90 patients hospitalized for treatment of a major depressive episode according to DSM-IV, platelet counts were performed after a 6 d antidepressant-free run-in period and again after 35 d of active standardized treatment with amitriptyline ( n = 40) or paroxetine ( n = 50). Results. – There was a trend for platelet counts to increase during treatment with amitriptyline (from 245.5 ± 68.6 to 256.8 ± 69 cells × 10 9 L –1 , P 9 L –1 , n.s). Conclusion. – Treatment with amitriptyline tends to be associated with elevated platelet counts. The cause for this increase is not known, but may be relevant in terms of patients’ long-term thromboembolic risk.