Vinpocetine

Vinpocetine (brand names: Cavinton, Intelectol; chemical name: ethyl apovincaminate) is a semisynthetic derivative alkaloid of vincamine (sometimes described as "a synthetic ethyl ester of apovincamine"),^[1] an extract from the periwinkle plant.

Vinpocetine is reported to have cerebral blood-flow enhancing^[2] and neuroprotective effects,^[3] and is used as a drug in Eastern Europe for the treatment of cerebrovascular disorders and age-related memory impairment.^[4]

Vinpocetine is widely marketed as a supplement for vasodilation and as a nootropic for the improvement of memory. In other words, Vinpocetine may help support brain functions such as concentration and memory by activating cerebral metabolism. A small subset of users report uncomfortable, adverse reactions to vinpocetine. A low initial dosage is ordinarily recommended.

Vinpocetine has been identified as a potent anti-inflammatory agent that might have a potential role in the treatment of Parkinson's disease and Alzheimer’s disease.^[5][6]

Controlled clinical trials

As of 2003 only three controlled clinical trials had tested "older adults with memory problems,"^[7] and these studies had promising results,^[7] in which a 2003 Cochrane review decided that the results were inconclusive.^[8]

Prior to 2003, a different study from 1985^[9] had tested young, healthy adults, but this study had 12 subjects and used a short treatment period.^[7]

Use as a vasodilator

Vinpocetine is widely used in the body building community as a vasodilator. Although no studies have been conducted on the effectiveness of vinpocetine on performance enhancement during exercise, in trial both beneficial and adverse effects have been reported on body building forums.

Anti-inflammatory action

Vinpocetine has been identified as a novel anti-inflammatory agent.^[5][6] Vinpocetine inhibits the up-regulation of NF-κB by TNFα in various cell tests. Reverse transcription polymerase chain reaction also shows that it reduced the TNFα-induced expression of the mRNA of proinflammatory molecules such as interleukin-1 beta, monocyte chemoattractant protein-1 (MCP-1), and vascular cell adhesion molecule-1 (VCAM-1). In mice, vinpocetine reduced lipopolysaccharide inoculation induced polymorphonuclear neutrophil infiltration into the lung.^[5][6] Neuroinflammatory processes can result in neuronal death in Parkinson's disease (PD) and Alzheimer’s disease (AD). It has been suggested that "it would be interesting to test whether vinpocetine’s antiinflammatory properties would have a protective effect in models of neurodegenerative conditions such as AD and PD."^[6]

Mechanism of action

Vinpocetine has been shown to selectively inhibit voltage-sensitive Na+ channels, resulting in a dose-dependent decrease in evoked extracellular Ca+ ions in striatal nerve endings.^[10] The Na+ channel inhibiting properties of vinpocetine are thought to contribute to a general neuroprotective effect through blockade of excitotoxicity and attenuation of neuronal damage induced by cerebral ischemia/reperfusion.^[11]

Vinpocetine is also a phosphodiesterase (PDE) type-1 inhibitor,^[12] (with an IC₅₀ of approximately 10⁻⁵ M.) leading to increases in intracellular levels of cyclic guanosine 3'5'-monophosphate (cGMP), an action that causes the vasorelaxant effects of vinpocetine on cerebral smooth muscle tissue.^[13][14]

Independent of vinpocetine's action on PDE, vinpocetine inhibits IKK preventing IκB degradation and the following translocation of NF-κB to the cell nucleus.^[5][6]

Increases in neuronal levels of DOPAC, a metabolic breakdown product of dopamine, have been shown to occur in striatal isolated nerve endings as a result of exposure to vinpocetine.^[15] Such an effect is consistent with the biogenic pharmacology of reserpine, a structural relative of vinpocetine, which depletes catecholamine levels and causes depression as a side effect of the cardiovascular and anti-psychotic effects.^[15] However, this effect tends to be reversible upon cessation of Vinpocetine administration, with full remission typically occurring within 3–4 weeks.

Side effects

Vinpocetine is generally tolerated well and without many cases of adverse reaction reported.^[16] No serious side effects have been reported in any clinical trials,^[17] although none of these trials have been long-term.^[8] According to a Dr. Wollschlaeger, "a critical review of the literature has reported no adverse effects. Vinpocetine appears to be safe, without any adverse affects. The only reported side effect, in a very small number of cases, was a slightly upset stomach, which is almost always a side effect for some people taking herbs. We have not seen any adverse effects or drug-herb interactions, and it seems safe to take with other drugs, including diabetes drugs, and blood thinners like Coumadin."^[18]

The safety of vinpocetine in pregnant women has not been evaluated.

Vinpocetine has been implicated in one case to induce agranulocytosis,^[19] a condition in which granulocytes are markedly decreased. Some people have anecdotally noted that their continued use of vinpocetine reduces immune function. Commission E warned that vinpocetine reduced immune function and could cause apoptosis in the long term.^[20]

Other alkaloids extracted from the periwinkle family, including Vincristine and Vinblastine are powerful chemotherapeutic agents which impair formation of microtubules and thus growth of related cancers, intestinal epithelium and bone marrow.

Dosage

It is recommended that first-time users ingest only 2–5 mg of vinpocetine with meals to make sure they are not hypersensitive to it. Users may then increase the dosage to 10–40 mg a day (which may, although very rarely, cause some light side effects).

External links

• Erowid Vinpocetine Vault
• Vinpocetine article from PDRhealth
• Vinpocetine for cognitive impairment and dementia - Cochrane review
• Information about Vinpocetine

References