This popular hay fever and allergy medication could be linked to dementia risk
Antihistamines are a go-to remedy for those suffering from hay fever and allergies, offering relief from symptoms like sneezing, watery eyes, and a runny nose. But recent research suggests that these common medications may carry a hidden risk, particularly for brain health.
Dr. Anthony L. Komaroff, editor of Harvard Health Letter, acknowledged the growing concerns over antihistamines and their potential link to dementia.
In response to a question about the risks of using the allergy tablets, Dr Komaroff said: “You raise an important question, but you might not like my answer. I assume you'd like a definite answer, like 'No, don't worry' or 'Yes, so look for another kind of treatment for your allergies.' However, all I can say, based on conflicting evidence, is 'Maybe.'”
READ MORE: New DWP plans for people on PIP with back, joint, and muscle health conditions due this month
READ MORE: People over State Pension age living on their own could be due £4,200 income boost
Antihistamines work by blocking histamine, a chemical released by the immune system that causes allergic reactions. While these drugs are effective at easing allergy symptoms, some, especially older versions, may have anticholinergic effects, meaning they can interfere with neurotransmitters in the brain.
Dr Komaroff explained: “Many frequently used medicines, including nonprescription medicines, have what are called anticholinergic effects. Examples include antihistamines... medicines used by millions of people.”
These medications may potentially increase the risk of dementia by blocking acetylcholine, a neurotransmitter important for memory and learning, or by increasing brain inflammation. However, Dr Komaroff notes that the research on this issue is not clear-cut.
“In the past decade, several studies have suggested that these pills might increase the risk of dementia, while other studies have found no risk. And all the studies are inherently flawed,” he said.
The difficulty in drawing definitive conclusions lies in the limitations of existing studies. A flawless study would require following identical twins over several decades, with one twin using anticholinergic medications and the other not.
However, such a study would be impractical, as Dr Komaroff pointed out. He said: “Obviously, such a study would not be feasible. Even if it were, it would take 60 years to get an answer — too long for you or me."
Despite the lack of conclusive evidence, Dr Komaroff takes a cautious approach to using antihistamines. He said: “I think twice about taking antihistamines and other medicines with anticholinergic effects. I weigh the symptom relief they give me against the possibility that they may slightly increase my risk of developing dementia.”
He also recommended considering other treatment options, saying: “I ask if there are other drugs that might also give me symptom relief, without the theoretical risk of cognitive decline. I also use the lowest possible dose to get symptom relief.”
While the potential link between antihistamines and dementia remains uncertain, experts recommend using second-generation antihistamines, such as cetirizine or loratadine, as they are less likely to cross the blood-brain barrier and cause cognitive issues.
However, as Dr Komaroff emphasised, more research is needed. He added: “As more studies are published, I'll keep you posted about the possible risks of these medicines."
