Weak studies on huperzine A for Alzheimer’s disease
I’m surprised by the position of the Alzheimer’s Association regarding huperzine A (shuangyiping). “Evidence from small studies shows that the effectiveness of huperzine A may be comparable to that of the approved drugs.”
Really?
Maybe they know something I don’t, but my search of the literature produces lots of animal studies and enthusiasm, but after more than 15 years since publication of the first clinical trial, the supportive data in people are lacking.
- 160 patients, some with senile dementia or senile and presenile simple memory disorders
- Huperzine A or placebo was injected intramuscularly twice daily for 2 weeks
- The “curative” effect of huperzine A was significant based on the Wechsler memory scale
“Curative” after 2 weeks? Not likely.
- 60 days of treatment to compare capsules to tablets of huperzine A
- Another blinded study, but between 2 active treatments, not placebo
- Significant improvement compared to baseline
- No differences between groups
60 days? Try again.
A typical pattern of response to Alzheimer’s treatment is shown in Figure 1 of the product information for donepezil (Aricept). It shows that an early positive response even to placebo for up to 60 days is not unusual. Long-term follow-up is necessary.
- The Chinese translation is bad, so we’ll do the best we can
- Huperzine A alone at apparently sub-therapeutic doses was compared to nilestriol (estrogen replacement therapy) plus huperzine A in 60 women with Alzheimer’s disease
- Not a blinded study — the investigators and the patients knew what they were taking
- Significant improvement at 24 weeks in the combination treatment group vs huperzine A alone
Based on this study, we still don’t know if huperzine A is effective when used alone or how much it contributes to estrogen replacement therapy.
The National Institute on Aging is sponsoring a clinical trial of huperzine A in patients with Alzheimer’s disease. It is scheduled to be completed this December. Perhaps we’ll know more next year.
Since this summary was originally posted, a PubMed search failed to reveal any new studies in humans using huperzine A to treat dementia or Alzheimer’s disease.
10/21/06 21:26 JR
