What is the relationship between Diphenhydramine (Benadryl) and dementia?

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Last updated: April 15, 2025View editorial policy

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From the Guidelines

Benadryl (diphenhydramine) should be avoided in older adults due to its association with an increased risk of dementia with long-term use, as suggested by the most recent and highest quality study 1.

Key Points to Consider

  • Anticholinergic medications like Benadryl block acetylcholine, a neurotransmitter crucial for memory and learning, potentially increasing dementia risk when used regularly for three years or more.
  • For allergies or occasional sleep issues, consider non-sedating antihistamines like loratadine (Claritin) or cetirizine (Zyrtec) instead, which don't cross the blood-brain barrier as readily.
  • If currently taking Benadryl regularly, don't stop abruptly but consult a healthcare provider about safer alternatives.
  • The risk appears dose-dependent, meaning higher doses and longer duration of use create greater concern.
  • Occasional use for acute allergic reactions is still considered safe for most people, but regular use should be avoided when possible, especially in older adults.

Evidence Supporting the Recommendation

The study published in the Mayo Clinic Proceedings 1 highlights the risks associated with anticholinergic medications, including Benadryl, in older adults, emphasizing the importance of careful medication management to prevent adverse outcomes such as dementia.

Alternatives and Considerations

  • Non-sedating antihistamines are preferred for managing allergies or sleep issues in older adults.
  • Healthcare providers should be consulted before stopping or changing any medication regimen.
  • The dose and duration of Benadryl use are critical factors in assessing the risk of dementia.

From the Research

Relationship Between Benedryl and Dementia

  • There is evidence to suggest that diphenhydramine, the active ingredient in Benedryl, may have adverse effects on cognitive function in older adults, which could be relevant to patients with dementia 2.
  • A study published in 2001 found that hospitalized older patients who received diphenhydramine were at an increased risk for delirium symptoms, including inattention, disorganized speech, and altered consciousness 2.
  • The same study also found a dose-response relationship between diphenhydramine use and adverse outcomes, including cognitive decline and longer hospital stays 2.
  • However, it's worth noting that the studies provided do not specifically examine the relationship between Benedryl and dementia, but rather the effects of diphenhydramine on cognitive function in older adults 2.
  • Other studies focus on treatment options for agitation in dementia, such as acetylcholinesterase inhibitors, memantine, and atypical antipsychotics, but do not mention Benedryl or diphenhydramine as a treatment option 3.
  • Additionally, a study on the neurocognitive effects of melatonin treatment in individuals with Alzheimer's disease and insomnia does not mention Benedryl or diphenhydramine 4.

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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