Treatment of the Raynaud's phenomenon with piracetam.

Abstract

Piracetam (Nootropil, CAS 7491-74-9) has been investigated in the treatment of primary and secondary Raynaud's phenomenon in three sequential and complementary studies. The first study in 20 patients with primary Raynaud's phenomenon, utilising clinical and ultrasound examination, capillaroscopy and laboratory tests established a daily dose of 8 g as most effective. The second study in 58 patients (47 primary, 11 secondary) confirmed the therapeutic efficacy of piracetam in both primary and secondary Raynaud's phenomenon. The third study, of crossover design, in 30 patients with severe Raynaud's syndrome, examined various agents given singly or in combination. The results not only confirmed the efficacy of piracetam but in addition allowed comparison of the efficacy of the principal therapeutic agents or regimens used in the treatment of Raynaud's syndrome and the formulation of a list of these therapies in decreasing order of efficacy, thus: piracetam 4 g/d + buflomedil 600 mg/d; piracetam 8 g/d; buflomedil 600 mg/d; piracetam 4 g/d + acetylsalicylic acid 100 mg/d; pentoxifylline 1200 mg/d; calcium antagonists; ketanserin 120 mg/d. The particular efficacy of 8 g piracetam daily in 3 divided doses at 8-hourly intervals can be attributed to its unique dual mode of action; inhibition of platelet function by inhibition of thromboxane A2 synthetase or antagonism of thromboxane A2 and increased formation of prostaglandin I2, together with a rheological effect involving reduction in blood and plasma viscosity through an increase in cell membrane deformability and a reduction of 30-40% in the plasma concentrations of fibrinogen and von Willebrand's factor. In addition, the administration of piracetam appears to be devoided of adverse effects