Vinpocetine: Inconclusive Evidence
Vinpocetine is a biosynthetic supplement derived from alkaloid found in the Periwinkle plant called Vinca minor, and is used as a drug in Eastern Europe for the treatment of cerebrovascular disorders and age-related memory impairment, since it has been reported to have cerebral blood-flow enhancing and neuroprotective effects. Nevertheless, the drug is not yet approved in the United States for pharmaceutical use, but just dietary supplement, modality in which is commonly used as a vasodilator that has anticonvulsant and anti-inflammatory action.
Unfortunately, most vinpocetine studies were performed before the 1990s. According to this meta-analysis , studies involve around 583 people with dementia treated with vinpocetine or placebo. The reports of these studies did not make possible any differentiation of effects for degenerative or vascular dementia. The results show benefit associated with treatment with vinpocetine 30mg/day and 60 mg/day compared with placebo, but the number of patients treated for 6 months or more was small. Only one study extended treatment to one year, and adverse effects were inconsistently reported and without regard for relationship to dose. The available data do not demonstrate many problems of adverse effects but intention-to-treat data were not available for any of the trials.
Thus, there is only one study available about the effects of vinpocetine in healthy subjects. Twelve healthy female volunteers received pre-treatments with vinpocetine 10, 20, 40 mg and placebo for two days according to a randomised, double-blind crossover design. On the third day of treatment and 1 h following morning dosage, subjects completed a battery of psychological tests in order to measure cognitive performance. No statistically significant changes from placebo were observed, or subjective ratings of drug effects. However, memory as assessed using the Sternberg technique -very specific- was found to be significantly improved following treatment with vinpocetine 40 mg when compared to placebo and results suggested a localised effect of the drug on the serial comparison stage of the reaction process . Nevertheless, results from this study must be replicated since the limited size of the population.
Thus, although the basic science is interesting, the evidence for beneficial cognitive effect of vinpocetine is inconclusive and does not support clinical use, even though the drug seems to have few adverse effects at the doses used in the studies. Large studies evaluating the use of vinpocetine for both people suffering from well-defined types of cognitive impairment and the healthy ones are needed to explore possible nootropic efficacy of this treatment.
