Interstitial pneumonia induced by ticlopidine

A 67-year-old female non-smoker, who had been diagnosed with familial hypercholesterolemia associated with severe atherosclerosis of the coronary, carotid and vertebral arteries, developed interstitial pneumonia 4 months after initiating ticlopidine to inhibit platelet aggregation. The lymphocyte stimulation test by ticlopidine was positive and bronchoalveolar lavage fluid showed an increase in lymphocytes and a decrease in the CD4+/8+ ratio, suggesting potentially undesirable side effects of ticlopidine. Two months after ticlopidine therapy was discontinued and prednisolone therapy started, the interstitial pneumonia had almost completely resolved. Two patients, one with ticlopidine-associated bronchiolitis obliterans organizing pneumonia and the other with pneumonia with multiple nodules, have been reported to date and the present patient is the third reported case of ticlopidine-induced pneumonia. The incidence of this side effect may not be so high because approximately 20 years have passed since ticlopidine was first marketed in Japan, but because the drug is now widely prescribed, this serious clinical side effect should be considered.