Piracetam for dementia or cognitive impairment

Background

Piracetam is a drug that may enhance memory and other intellectual functions, but its usefulness in treating dementia is uncertain. It is, however, commonly prescribed for cognitive impairment and dementia in several countries of continental Europe.

Objectives

To determine the clinical efficacy of piracetam for features of dementia (classified into the major subtypes: vascular, Alzheimer's disease or mixed vascular and Alzheimer's disease, or unclassified dementia) or cognitive impairment not fulfilling diagnostic criteria for dementia.

Search strategy

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 17 December 2007 using the terms piracetam, nootropic and 2-Oxo-1-pyrrolidine. A review by employees and consultants of the manufacturing company, UCB Pharma (Waegemans 2002) included data from unpublished studies not made available to Cochrane reviewers.

Selection criteria

All unconfounded, randomized, double-blind in which treatment with piracetam was administered for more than a day and compared with placebo in people with dementia of Alzheimer type, vascular dementia, or mixed vascular and Alzheimer's disease, or unclassified dementia, or cognitive impairment not fulfilling diagnostic criteria for dementia.

Data collection and analysis

Two reviewers independently extracted data from studies fulfilling inclusion criteria. Intention-to-treat analysis was used where feasible and studies were pooled if appropriate. Sensitivity analyses were to be performed to determine if studies performing poorly on quality criteria affected results. The pharmaceutical company marketing piracetam did not release the results of several unpublished trials.

Main results

Many studies were of cross-over design and first-phase data were unavailable, or could not be extracted. Global Impression of Change (GIC) was the only outcome for which pooling of data was possible, involving only four studies. There was evidence of heterogeneity in the results, chi-square test = 19.17 (df = 3, P < 0.001). The OR for improvement in the piracetam group compared with placebo was 3.43 (95% CI 2.32 to 5.07). Using a fixed-effects model the OR for improvement with piracetam compared with placebo was 3.55 (95% CI 2.45 to 5.16). This estimate was derived from completers rather than from an intention-to-treat analysis as relevant data could not be extracted from the reports.

In the limited data available no significant differences were found between treatment and placebo groups for cognition (immediate memory, visuospatial, MMSE, delayed memory or speech) for dependency, or for depression.

The large volume of unpublished and untraceable data not available to the reviewers raises the possibility of publication bias.

Authors' conclusions

Published evidence does not support the use of piracetam in the treatment of people with dementia or cognitive impairment. Although effects were found on global impression of change, no benefit was shown by any of the more specific measures of cognitive function.

The evidence indicates a need for further evaluation of piracetam.