Galantamine sold as prescription generic drugs was labeled accurately and free of contamination, but galantamine sold as dietary supplements was not, an analysis showed.
Across 10 brands of dietary supplements, the actual quantity of galantamine -- a plant alkaloid with anticholinergic effects used to treat Alzheimer's dementia -- was anywhere from 2% to 110% of the labeled quantity, reported Pieter Cohen, MD, of Cambridge Health Alliance in Massachusetts, and colleagues in a research letter.
In contrast, the amount of galantamine in 11 brands of generic drugs ranged from 97.5% to 104.2% of the labeled content.
Moreover, three of the over-the-counter dietary supplements were contaminated with Bacillus cereus sensu stricto, which may suggest a lack of appropriate quality control during manufacturing, the researchers noted.
"What we found was a striking difference between the products," Cohen noted in an email to .
"Generic galantamine aced the tests. The amount of galantamine listed on the label accurately represented the amount of galantamine in the pills and, importantly, no bacterial contamination was found," he said.
"The galantamine dietary supplements, on the other hand, almost universally failed our tests: 90%, or 9 out of the 10 brands, had an inaccurate amount of galantamine on the label and, disturbingly, 30%, 3 out of 10 brands, were also contaminated with bacteria that could, if consumed at higher levels, cause diarrheal illnesses."
Galantamine is derived from botanical sources including and . Prescription galantamine (Razadyne) in 2001 and several generic brands are now sold. The cholinesterase inhibitor is indicated for mild to moderate dementia in Alzheimer's and has been shown to of severe dementia.
Galantamine appears to be ineffective in treating mild cognitive impairment or preventing dementia, but the supplement is marketed for a variety of cognitive conditions.
"When sold as a dietary supplement, manufacturers claim galantamine can improve memory, initiate lucid dreams, and improve 'cognitive acuity,' but what's actually in those bottles of galantamine and how that compares to prescription galantamine is not known," Cohen said.
In June 2023, Cohen and co-authors purchased all dietary supplements available on Amazon that were labeled with galantamine as an ingredient and carried a supplement facts panel (to ensure the product was marketed as a dietary supplement). The supplements were bought online in the U.S.
In September 2023, they purchased all generic immediate-release formulations of galantamine available in the U.S. Generic drugs were labeled as containing 4, 8, and 12 mg of galantamine per tablet or capsule.
The contents of all products were reconstituted in water and analyzed for the presence of galantamine. The researchers also assessed the products for possible contamination with microorganisms.
Overall, 100% of the generic drugs and only one supplement (10%) contained a quantity of galantamine that was within 10% of the quantity declared on the label.
Clinicians should query patients with memory concerns about their use of dietary supplements and advise patients not to use galantamine supplements, Cohen and colleagues said.
"For patients with Alzheimer's disease, use of galantamine supplements instead of generic galantamine may adversely affect their care," they pointed out.
"Furthermore, the sale of inaccurately labeled galantamine supplements promoted for nonspecific memory and other cognitive problems is concerning given the lack of proven efficacy, potential drug-drug interactions, and adverse effects, including nausea, vomiting, dizziness, bradycardia, and syncope," they added.
The study has several limitations, the researchers acknowledged. Galantamine supplements were purchased at one time point only and findings might not apply to products available at other times. Whether results are generalizable to other substances like niacin, potassium, or iron that also are available as either supplements or drugs isn't known, they added.
"Our study raises a troubling question: Are the laws regulating dietary supplements in the U.S. adequate to ensure the quality of the many active drugs sold directly to U.S. consumers as supplements?" Cohen asked. "We think not."
Disclosures
Cohen reported receiving grants from Consumers Union and PEW Charitable Trust and personal fees from UpToDate and the CDC outside the submitted work.
Co-authors had no disclosures to report.
Primary Source
JAMA
Cohen PA, et al "Accuracy of labeling of galantamine generic drugs and dietary supplements" JAMA 2024; DOI: 10.1001/jama.2024.0328.