Safe To Take Benadryl For Sleep All The Time?
In our latest question and answer, the pharmacist discusses if the long-term use of Benadryl for sleep is safe.
Is it OK to take Benadryl (diphenhydramine) as a sleep aid regularly? I read that it may contribute to dementia.
While Benadryl (diphenhydramine) can safely be used once in a while as a sleep aid, long-term use is not recommended for multiple reasons.
Even the intermittent use of Benadryl for sleep isn't generally recommended if you are elderly (over 65).
Studies show that the elderly population doesn't metabolize Benadryl as quickly and are far more susceptible to the negative side effects of the drugs. For example, it can precipitate glaucoma, cause urinary retention and increase the risk of confusion in older adults.
The American Geriatrics Society 'Beers criteria', which discusses inappropriate medication use in the elderly, recommends against the use of Benadryl due to its strong anticholinergic effects (more on this later in the article).
OBRA (Omnibus Budget Reconciliation Act) guidelines, which has recommended policies on medication use in long-term care facilities, states that it should not be used for more than 14 days due to the risk of side effects and lack of published efficacy.
In terms of Benadryl possibility causing dementia, long-term use of anticholinergic drugs has been associated with an increased risk of dementia and dementia-related diseases, like Alzheimer's.
Benadryl is one of many anticholinergic medications that are thought to increase the risk of dementia, but studies show that this risk appears to be in those aged 65 years and older.
An anticholinergic drug is one that blocks the action of acetylcholine, an abundant neurotransmitter in the body.
Acetylcholine has a wide range of effects, which would be an article in and of itself. In a nutshell, it acts as a messenger in both the central and peripheral system and is vitally important to both memory and learning processes. It also activates motors neurons and is necessary for muscle contractility.
A drug having 'anticholinergic effects' isn't always a bad thing though.
In fact, there are several drugs specifically designed as anticholinergics, which are used for everything from an overactive bladder (e.g. Detrol LA) to the treatment of Parkinson's Disease (e.g. Cogentin, Artane).
Unfortunately, many other drugs have anticholinergic properties, which cause a range of undesirable side effects. These include:
- Dry mouth
- Dry eyes
- Increased body temperature
There are a variety of mnemonic sayings that describe 'anticholinergic toxicity' to help to remember the potential negative effects of anticholinergic drugs. One such one is:
"Blind as a bat, dry as a bone, full as a flask (can’t urinate), hot as a hare (or hell, or Hades), red as a beet, mad as a hatter, tacky (tachycardic) as a leisure suit (pink flamingo)".
Drugs often associated with their anticholinergic effects include:
- First-generation antihistamines (e.g. Benadryl)
- Tricyclic antidepressants
Anticholinergics are also fairly strongly associated with memory loss and an increased risk of dementia in those 65 years old and over.
Multiple studies warn against the long-term use of anticholinergics in the elderly due to this risk.
It isn't know how long anticholinergic drugs need to be taken to increase the risk of dementia, but one of the largest studies on the matter, published in JAMA Internal Medicine, reported a strong link between those taking high levels of anticholinergic medicines for more than three years and the onset of dementia.
The next section will focus on Benadryl.
Benadryl Anticholinergic Effects
First-generation antihistamines like Benadryl are strongly associated with anticholinergic effects.
These effects can be seen in many people taking the drug but the effects are far more pronounced in 65 years of age and older.
They are more likely to experience negative side effects in a more severe manner. These effects include:
- Memory loss
- Dry mouth
- Increased risk of falls
Benadryl, since it does have strong anticholinergic effects, is generally lumped into drugs that increase the risk of dementia with long term use in those over 65.
Benadryl As A Sleep Aid
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