You can find out more about NPF's National
Medical Director, Dr. Michael S. Okun, by also visiting the NPF Center of
Excellence, University of Florida Health Center for Movement Disorders
and Neurorestoration. Dr. Okun is also the author of the Amazon #1
Parkinson's Best Seller 10 Secrets to a
Happier Life.
Parkinson’s disease patients frequently
struggle to identify drug therapies that can address bothersome symptoms such
as sleep dysfunction, bladder urgency, drooling, and tremor. Many of the
drug therapies such as Benadryl (diphenhydramine), Advil PM, Alleve PM, common
antihistamines, and others pills are readily available over the counter and do
not require a prescription. These medications block a cholinergic
receptor in the brain, and can improve many Parkinson’s disease symptoms.
However, the price of taking these drugs may be steep (thinking problems,
confusion, unsteadiness and even falling). An older French study of
hospitalized Parkinson’s disease patients revealed that though 46% of all demented
patients were confused, 93% on anticholinergic therapy had delirium and
confusion when in the hospital (Agid et. al.). Deficiencies of the
chemical acetylcholine have been reported to underpin thinking issues and
shortages of the chemical have been observed in the brainstem, hippocampus, and
cortex of Parkinson’s disease patients. Though anticholinergic use can
result in drowsiness, dry mouth, urinary retention, memory problems as well as
constipation, many patients find these therapies useful. In this month’s
What’s Hot column we will address the short and long-term potential side
effects of using of anti-cholinergic medications in Parkinson’s disease.
Cooper and colleagues in 1992 addressed
thinking ability in a group of 82 freshly diagnosed and untreated Parkinson’s
disease patients. The patients in this study were all randomized to
receive levodopa (Sinemet), bromocriptine (a dopamine agonist) or an
anticholinergic drug. Though all three treatments improved motor performance,
the anticholinergic drugs produced memory impairments. Many subsequent
studies including the National Parkinson Foundation QII prospective study have
confirmed these findings.
Perry and colleagues in 2003 investigated the
idea that blocking brain acetylcholine receptors could lead to more
“Alzheimer’s changes” in the Parkinson’s disease brain. Interestingly,
the researchers reported that an important marker of Alzheimer’s disease, the
amyloid plaque density, was present in more than double the concentration in
Parkinson’s disease patients treated with long-term anticholinergic therapy.
Another marker of Alzheimer’s disease, the neurofibrillary tangle, was also
more prominent in the brains of those taking anticholinergic drugs.
The most recent worrisome evidence surrounding
anticholinergic therapy is drawn from an article in a recent issue of JAMA
Internal Medicine written by pharmacist Shelly Gray. The authors utilized
data from the Adult Changes in Thought Study. The investigation was based in
Washington state and had an impressive 3434 people enrolled who were 65 years
or older. All study participants were screened at inclusion to be sure
there was no evidence for dementia. The authors cleverly used
computerized pharmacy data to assess each participant’s exposure to anticholinergic
drugs. The most common anticholinergic drugs were old-fashioned tricyclic
antidepressants (TCA’s), antihistamines, and also drugs used for bladder and
sleep. The patients were followed for 7 years and the data revealed that over
20% were shown to develop dementia. Participants who took anticholinergic drugs
for three years or more had a greater than 50% higher dementia risk.
Also, a higher cumulative dose of anticholinergic drugs increased the risk for
dementia when compared to those taking anticholinergic drugs for 90 days or
less.
The bottom line for Parkinson’s disease
patients is that there should be a greater awareness of the short and the
long-term potential side effects of anticholinergic therapy. Short-term,
Parkinson’s disease patients should be aware that anticholinergics may
precipitate drowsiness, dry mouth, urinary retention, memory problems, blurry
vision, and constipation as well as a host of other side effects.
Long-term, there is an increased risk of dementia. It is important for
Parkinson’s disease patients to routinely review medication lists with both a
doctor and a pharmacist and to try to identify other medication alternatives.
Some practical suggestions include:
• Identify alternative antidepressants with
less anticholinergic effects
• Watch out for over the counter drugs like
Benadryl (diphenhydramine) and antihistamines
• Dopamine agonists, levodopa, and deep brain
stimulation can all potentially be used for difficult to control tremor instead
of anticholinergics
• Botulinuma toxin injections can be employed
for drooling and for some cases of bladder dysfunction
• Sometimes atropine drops under the tongue or
chewing gum can be employed for drooling issues
• A type of physical therapy referred to as
pelvic floor rehabilitation can be helpful for bladder retraining in those with
urinary frequency
• If hospitalized be sure the doctors do not
use anticholinergics for sleep or bladder dysfunction
Parkinson’s disease patients and their
interdisciplinary care teams can usually work together to reduce or to
eliminate anticholinergic drug use
http://www.parkinson.org/whatshot
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