Cilostazol and several of its metabolites are inhibitors of phosphodiesterase III. Several drugs with this pharmacologic effect have caused decreased survival compared to placebo in patients with class III-IV congestive heart failure. Pletaal is contraindicated in patients with congestive heart failure of any severity. Pletaal is contraindicated in patients with haemostatic disorders or active pathologic bleeding, such as bleeding peptic ulcer and intracranial bleeding. Pletaal inhibits platelet aggregation in a reversible manner. Pletaal is contraindicated in patients with known or suspected hypersensitivity to any of its components.