Medications that increase the risk of dementia

A new study at the University of Washington provides strong evidence that certain popular drugs may increase the risk of dementia in older adults. The drugs share some common mechanisms within the key areas of the brain, but are mainly used as over-the-counter ingredients for sleep, cough, cold and allergy medicine, as well as for the treatment of overactive bladder and depression.

Medications and dementia

The most commonly used drug related to dementia is diphenhydramine, which is used in many popular products such as Benadryl, Nytol Sominex, Theraflu, Triaminic Allergy, etc. It is also involved in drugs that contain chlorpheniramine (Aller-Chlor); oxybutynin (Ditropan) and tolterodine (Detrol) for overactive bladder; and tricyclic antidepressants, such as doxepin or amitriptyline.

Background data

Acetylcholine is a critical brain chemical involved in nerve impulse transmission and is especially important for good memory and cognitive function. For example, Alzheimer’s disease is associated with a severe reduction in acetylcholine levels due to reduced activity of the enzyme that makes acetylcholine (choline acetyltransferase).

Given the relationship between low levels of acetylcholine and poor brain function, including dementia, previous studies have linked certain drugs with the reduction of acetylcholine activity, as well as mild cognitive impairment. These medications include those mentioned above.

Although it is believed that the interruption of drugs reverses mental deficit, there is evidence that anticholinergic drugs can produce permanent changes that lead to irreversible dementia.

It is known that these drugs cause drowsiness or short-term confusion, which is included in the prescription information, but the long-term effects that these medications have on mental function are generally not known to the doctors or the people who take them.

Medications that increase the risk of dementia

A new study at the University of Washington provides strong evidence that certain popular drugs may increase the risk of dementia in older adults. The drugs share some common mechanisms within the key areas of the brain, but are mainly used as over-the-counter ingredients for sleep, cough, cold and allergy medicine, as well as for the treatment of overactive bladder and depression.

New data

To assess whether the cumulative use of anticholinergics is associated with an increased risk of incident dementia, the researchers examined the medical records of 3,434 participants aged 65 and older without dementia at the start of the study. Initial recruitment occurred from 1994 to 1996 and from 2000 to 2003, and data as of September 30, 2012 were also included in these analyzes.

Exposure to anticholinergic drugs was determined from computerized pharmaceutical records. The accumulated exposure was updated as the participants were followed up over a period of 10 years. About 20% of the population was using anticholinergic medications.

During the evaluation period, 797 participants (23.2%) developed dementia, of which 637 (80%) developed Alzheimer’s disease. A 10-year cumulative dose-response relationship was observed for dementia and Alzheimer’s. In other words, the greater the cumulative anticholinergic use, the greater the risk of dementia. The highest risk threshold was to take the minimum daily effective dose of one of the anticholinergic agents every day for 3 years.

Even at low doses or recommended levels, chronic use of these medications should be avoided.

Based on these results, the authors of the study propose efforts to increase awareness among health professionals and older adults about the risk of using these medications over time.

Conclusion

The results of this study highlight the importance of avoiding the long-term use of such medications, including diphenhydramine and over-the-counter sleeping pills. What this research further establishes is that the human brain can be adversely affected by minor pharmacological agents, highlighting the importance of using natural approaches that not only address the key issue (e.g., insomnia, allergies, etc.) but also have a positive effect on brain function. For example, the enzymatically modified natural isoquercitrin compound (EMIQ) has shown significant anti allergic effects and has also been shown to block the formation of beta-amyloid, a protein that is linked to causing brain damage in Alzheimer’s disease.