Huperzine A treatment of Alzheimer’s disease
Most drugs used to treat Alzheimer’s disease are classified as cholinesterase inhibitors.
Researchers in California and Washington DC studied huperzine A, a natural cholinesterase inhibitor derived from the Chinese herb Huperzia serrata.
First, the details.
- 210 people with mild to moderate Alzheimer’s disease were randomly assigned to a treatment group for at least 16 weeks.
- Placebo
- Huperzine A 200 mcg taken twice daily
- Huperzine A 400 mcg taken twice daily
- The cognitive effects of huperzine A 200 mcg at week 16 were compared to placebo.
- Also, the effects of huperzine A 400 mcg were evaluated using a battery of tests.
And, the results.
- Huperzine A 200 mcg twice daily showed no effect.
- Huperzine A 400 mcg twice daily showed significant improvement in ADAS-Cog at 11 and 16 weeks vs a decline with placebo group.
- ADAS-cog is the most popular cognitive test used in research.
- Changes in clinical global impression of change using the Neuropsychiatric Inventory (NPI) and activities of daily living were not significant at either dose.
- NPI is a tool to assess psychopathology in patients with dementia and other neuro-psychiatric disorders.
The bottom line?
In this “dose-ranging study,” the primary endpoint of the research was any response to huperzine A 200 mcg. Based on this the authors concluded, “The primary efficacy analysis did not show cognitive benefit with huperzine A 200 mcg twice daily.”
Any future research is likely to focus on the 400 mcg twice daily dose.
A review from 2008 by researchers at the Mayo Clinic, in Rochester, Minnesota, listed several characteristics of huperzine A that suggest it might be beneficial in these patients.
- A potent, reversible, and selective inhibitor of acetylcholine esterase
- Rapid absorption and penetration into the brain in animal studies.
- Compared to the current cholinesterase inhibitors, huperzine A has a longer duration of action.
- Some studies suggest better tolerability due to fewer peripheral cholinergic side effects.
- Animal data and clinical safety tests to date have not identified any unexpected toxicity.
- Gastrointestinal complaints have been reported.
4/19/11 18:59 JR