Rumours have been circulating that regular use of antihistamines increases the risk of dementia. We took a look at the research in the field to see if there is any truth behind the sometimes sensationalist headlines…
A systematic review – a high-quality type of research paper – published in 2020 concluded that there is a link between antihistamines and dementia. The authors evaluated a range of studies available in the field, focusing on use of anticholinergic agents. These which re medications designed to block parts of the nervous system, employed to treat conditions like bladder dysfunction, Parkinson’s disease, and allergies (antihistamines). The literature review found that use of anticholinergic-containing medications for three months or more was associated with a 46% increased risk of dementia, compared to non-use.
Caveats of these results were that the studies included considered mostly bladder antimuscarinics, and the researchers did not assess whether this was a reversible risk factor. Despite this, the evidence would suggest caution for those routinely taking antihistamines.
Further science in the field suggests that the dementia risk is dose dependant when it comes to antihistamine usage. This was true for people taking both first-generation and second-generation medications, although further research is needed to determine the exact mechanisms at play.
And, of course, all of this needs to be balanced with the improved quality of life that they can deliver for those who suffer badly with allergies. The research proves than a number of active agents are highly effective in reducing common symptoms from nasal congestion and itching to sneezing.
So, should we be avoiding antihistamines? In truth, the jury is still out. Like any medication, it’s important that they are taken responsibly and any concerns should be discussed with an appropriately trained healthcare professional.
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