UK piracetam doctor says no

Thanks! I had actually not read that study.

The random administration of four different single oral doses of piracetam (Nootropil, CAS 7491-74-9)--1.6 g, 3.2 g, 4.8 g and 9.6 g--at fixed intervals of 2 weeks to 5 healthy subjects has confirmed and explicited its platelet anti-aggregant and rheological properties after doses of 4.8 g and 9.6 g. The effect on platelet aggregation occurs through inhibition of thromboxane synthetase or anti-thromboxane A2 activity together with a reduction in the plasma level of von Willebrand's factor (F.VIIIR:vW). The rheological effect is related to the action of piracetam on cell membrane deformability (red cells, white cells and platelets) and to its simultaneous effect in reducing by 30-40% plasma levels of fibrinogen and von Willebrand's factor. In addition, it exerts a direct stimulant effect on prostacyclin synthesis in healthy endothelium. These effects are greatest between 1 and 4 h after dosage, and then diminish progressively to disappear between 8 and 12 h after administration. This explains the need to divide the total daily dose into 3 intakes at 8-hourly intervals. This study confirms the presence of four sites of action of piracetam: the vessel wall, platelets, plasma and cell membranes (RBC, WBC), which provide the basis for the potentially important antithrombotic activity of piracetam.

Those are very high doses, though. Also, inhibiting platelet aggregation at high doses does not mean it causes hemorrhaging. But that study does make it clear that it should not be taken in high doses around the time of surgery. The doctor did not state that very high single doses can inhibit platelet aggregation for four hours. He stated that piracetam can cause hemorrhaging, which is still unsubstantiated. If there are cases of it happening, I am unable to find them.