According to a population-based cohort study, use of cholinesterase inhibitors is associated with increased rates of syncope (loss of consciousness or fainting), bradycardia (slow heart rate), pacemaker insertion, and hip fracture in older adults with dementia and Alzheimer’s.
Alzheimer’s has become a major public health problem around the world due to its increasing prevalence, long duration, caregiver burden, and high financial cost of care. The degeneration of acetylcholine-containing neurons in the basal forebrain has been implicated in the symptoms of Alzheimer’s.
Cholinesterase inhibitors are commonly prescribed to treat Alzheimer’s and dementia with generally modest results. They prevent the breakdown of acetylcholine, but they do not work for all Alzheimer’s patients, some will improve, some will not and others will continue to deteriorate.
The researchers investigated the relationship between cholinesterase inhibitor use and syncope-related outcomes using health care databases from Ontario, Canada. They identified 19 803 community-dwelling older adults with dementia who were prescribed cholinesterase inhibitors (donepezil, galantamine, and rivastigmine) and 61 499 controls who were not.
Hospital visits for syncope were more frequent in people receiving cholinesterase inhibitors than in controls (31.5 vs 18.6 events per 1000 person-years). The treatment group also had higher rates of bradycardia, permanent pacemaker insertion, and hip fracture.
The study authors conclude that the risk of these previously under recognized serious adverse events must be weighed carefully against the drugs’ generally modest benefits.
Huperzine A, is a naturally occurring sesquiterpene alkaloid found in the plant extracts of the firmoss Huperzia serrata with the same same mechanism of action as the cholinesterase inhibitors, suggesting it could be a promising agent for clinical therapy of cognitive impairment in patients with Alzheimer’s.