Piracetam is a drug marketed as a treatment for myoclonus and a cognitive enhancer. Evidence to support its use is unclear, with some studies showing modest benefits in specific populations and others showing minimal or no benefit. Piracetam is sold as a medication in many European countries. In the United States, piracetam is sold as a dietary supplement, despite being prohibited by the FDA.
Piracetam is in the racetams group, with chemical name 2-oxo-1-pyrrolidine acetamide. It is a derivative of the neurotransmitter GABA and shares the same 2-oxo-pyrrolidone base structure with pyroglutamic acid. Piracetam is a cyclic derivative of GABA (gamma-Aminobutyric acid). Related drugs include the anticonvulsants levetiracetam and brivaracetam, and the putative nootropics aniracetam and phenylpiracetam.
A 2001 Cochrane review concluded that there was not enough evidence to support piracetam for dementia or cognitive problems. A 2005 review found some evidence of benefit in older subjects with cognitive impairment. In 2008, a working group of the British Academy of Medical Sciences noted that many of the trials of piracetam for dementia were flawed.
Some sources suggest that piracetam's overall effect on lowering depression and anxiety is higher than on improving memory. However, depression is reported to be an occasional adverse effect of piracetam.
Piracetam has been found to have very few side effects, and those it has are typically "few, mild, and transient." A large-scale, 12-week trial of high-dose piracetam found no adverse effects occurred in the group taking piracetam as compared to the placebo group. Many other studies have likewise found piracetam to be well tolerated.
Piracetam does not appear to be acutely toxic at the doses used in human studies.
The LD50 for oral consumption in humans has not been determined. The LD50 is 5.6 g/kg for rats and 20 g/kg for mice, indicating extremely low acute toxicity. For comparison, in rats the LD50 of vitamin C is 12 g/kg and the LD50 of table salt is 3 g/kg.
Mechanisms of action
Piracetam's mechanism of action, as with racetams in general, is not fully understood. The drug influences neuronal and vascular functions and influences cognitive function without acting as a sedative or stimulant. Piracetam is a positive allosteric modulator of the AMPA receptor, although this action is very weak and its clinical effects may not necessarily be mediated by this action. It is hypothesized to act on ion channels or ion carriers, thus leading to increased neuron excitability.GABA brain metabolism and GABA receptors are not affected by piracetam
In the United Kingdom, piracetam is approved as a prescription drug Prescription Only Medicine (POM) number is PL 20636/2524 for adult with myoclonus of cortical origin, irrespective of cause, and should be used in combination with other anti-myoclonic therapies.
In Japan piracetam is approved as a prescription drug.
Piracetam has no DIN in Canada, and thus cannot be sold but can be imported for personal use in Canada.
Brivaracetam — an analogue of piracetam with the same additional side chain as levetiracetam and a three–carbon chain. It exhibits greater antiepileptic properties than levetiracetam in animal models, but with a somewhat smaller, although still high, therapeutic range.
Levetiracetam — an analogue of piracetam bearing an additional CH3–CH2– sidechain and bearing antiepileptic pharmacological properties through a poorly understood mechanism probably related to its affinity for the vesicle protein SV2A.
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