Nootropics: preclinical results in the light of clinical effects; comparison with tacrine.

This review is meant to serve several purposes. First, it surveys the preclinical and clinical profiles of piracetam-like nootropics. Second, the conditions under which the nootropics are active in preclinical studies are identified and analyzed with a view of finding a common denominator that could explain the observed effects. Third, the clinical profile is examined, on the one hand to assess whether these drugs are in fact active in humans, and on the other to determine how the clinical effects of the nootropics compare with those of tacrine. Lastly, the clinical data are then further scrutinized to assess whether they fulfill the expectations based on the preclinical findings.