CLINICAL MISINFORMATION: THE CASE OF BENADRYL CAUSING DEMENTIA
May 22, 2013
In July 2010, Campbell, Boustani and colleagues published the results of a 6-year longitudinal observational study on the cognitive function of 1,600 African Americans over the age of 70 and the association with medications with anticholinergic side effects.[2] The study enrolled individuals who were cognitively normal at baseline. The participants were then reevaluated at least once for cognitive decline at 3 and 6 years of follow-up. Data on patient’s medications with anticholinergic side effects were based on participants reported medication use as well as over-the-counter and prescription bottles belonging to the patients.[3]
The results of the Campbell study are as follows: of the study participants, 179 of 1,652 (11%) were deemed to be exposed to “definite” anticholinergic medications. In that group, the odds ratio for “cognitive impairment” was 1.43, which was not statistically significant to a p-value of 0.05. When corrected based on the number of drugs with anticholinergic effects an individual was taking, the odds ratio for cognitive impairment was 1.46 with a p value of .0181. However, overall the authors conclude that their data did not support the hypothesis that the use of anticholinergic medications increased the risk of alzheimer’s dementia and that the results simply “suggested” a link between this class of medications and “mild cognitive impairment”.[2]
After forty-five minutes of researching and using information databases that are only accessible to me via my medical school library, I had found that the information my friend’s original fear was based on was at best inconclusive. A study with internal validity only to African-Americans over the age of 70 which “suggested” that anticholinergic use may be linked to mild cognitive impairment had, through the evolution of information, been applied to the general population and concluded that medications like Benadryl caused memory loss.
https://www.clinicalcorrelations.org/2013/05/22/clinical-misinformation-the-case-of-benadryl-causing-dementia/
It is generally accepted in in medicine that anticholinergic use does result in later symptomology (causal). I used to keep a list of references in my bookmarks but would have to re-search those now. There were multiple studies, not RCTs, of course, but convincing longitudinal studies. I myself was taken off an Rx drug for this reason.
Believe what you want.