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Evidence summaries

Cholinesterase Inhibitors for Alzheimer's Disease

Treatment with cholinesterase inhibitors appears to be effective in slightly improving cognitive function, activities of daily living and global assessment in people with mild to severe Alzheimer's disease. Level of evidence: "B"

The quality of evidence is downgraded by indirectness of evidence (short follow-up, surrogate outcomes).

Cholinesterase inhibitors are recommended for improving cognitive function, activities of daily living and global assessment in Alzheimer's disease.

The recommendation is strong because of possible positive effect on cognitive function, activities of daily living and global assessment. The cost of cholinesterase inhibitors is low.

A Cochrane review [Abstract] 1 included 13 studies with a total of 7 298 subjects with Alzheimer's disease (AD). The combined results of 10 placebo controlled trials demonstrate that treatment for 6 months with the cholinesterase inhibitors (ChEI) donepezil, galantamine or rivastigmine at the recommended dose produced improvements in cognitive function on average -2.7 points (95% CI -3.0 to -2.3), in the midrange of the 70 point ADAS-Cog Scale, for people with mild, moderate or severe AD. Study clinicians rated global clinical state more positively in treated patients. Benefits of treatment were also seen on measures of activities of daily living and behaviour. None of these treatment effects are large. The effects are similar for patients with severe AD, but there is evidence only from two trials. More patients leave ChEI treatment groups, 29%, on account of adverse events than leave the placebo groups (18%).

Clinical comments

Although the clinical benefits in the included studies were small, a treatment attempt is warranted due to the debilitating nature of the disease and its impact on the patient's quality of life.

    References

    • Birks J. Cholinesterase inhibitors for Alzheimer's disease. Cochrane Database Syst Rev 2006 Jan 25;(1):CD005593. [PubMed]

Primary/Secondary Keywords