I have used Vinpocetine on a number of occasions, for both short/intermittent periods as well as a few stints of prolonged use (20-30mg/day for 8-10 days), and have experimented with a range of dosages (2.5-35mg in small increments). I found it to be exceptionally effective on a very short-term basis, particularly for that last minute boost in a study session or during exercise. Its short half-life and myriad of side-effects prevent regular use, and eventually banished this one to the oddities shelf (with S.O.D, phenylpiracetam, modafinil...etc.). Vinpocetine and Piracetam are apples and oranges-- both nootropics but worlds apart.
Primarily, Vinpocetine acts as a vasodilator by inhibiting voltage-gated Na+ channels. This effect occurs throughout the body, not just in the brain. Some anecdotal evidence suggests that this may be beneficial in certain forms of exercise as well as in cognition- hence its employment as a nootropic.
In my experience, Vinpocetine has the shortest half-life of any nootropic I have encountered. In particular, the effects of Vinpocetine appear to be completely abolished by the t+1hr mark. Redosing has slightly diminished effect but certainly works, though definitely compounds the after-effects. This cessation of effects is usually accompanied by a marked 'come-down' or 'crash,' characterized by lethargy, anhedonia, and in higher-doses, some pretty gnarly head-aches. Its temporarily vasorelaxant properties responsible for relaxation of smooth muscle seem to rebound upon the come-down, which may be responsible for the head-ache, which at doses above 15mg can be pretty severe and not treatable with NSAIDs.
Vinpocetine has been shown to decrease catecholamine levels in the brain by enhancing metabolic breakdown-- this includes some of the more important neurotransmitters such as Dopamine, and may result in depression. I have noticed that after prolonged or frequent use of Vinpocetine, my general mood is characterized by notably flat-affect, amotivation, and a generally anhedonic nature. In other words, if taken regularly, this one should be ingested concomitantly with some catecholamine precursors such as L-DOPA, which may have side-effects of its own-- best to be avoided, in my opinion. No direct effect on acetylcholine utilization has been shown or noted, so a choline supplement is probably unnecessary.
If you have any more specific questions about Vinpocetine, feel free to PM me or ask here.
As matthias7 noted, Ginkgo-Biloba may be a more reasonable alternative. Ginkgo has been shown to exert similar effects on blood-flow (i.e. vasodilation) with significantly reduced side-effects, a greater half-life, and a longer history of human use. Though the efficacy of Gingko is widely debated, I have found it to be quite effective, though less directed than Vinpocetine. Gingko has also been shown to have a number of other beneficial properties outside of vasodilation (though that should probably be saved for another discussion).
Cliff Notes == Vinpocetine is not like Piracetam in nature of effect, does not require concomitant administration of choline, has an extremely short half-life and high side-effect profile, and is poorly tolerated by many individuals. Gingko-Biloba is a reasonable alternative as a vasodilator.
