Anticholinergics
Anticholinergics are older drugs, less commonly prescribed these
days, that can have a mild effect on the symptoms of Parkinson's by
blocking the action of the chemical messenger acetylcholine.
These are:
- trihexyphenidyl (Broflex, Artane, Agitane)
- benztropine (Cogentin)
- orphenadrine (Disipal)
- procyclidine (Kemadrin, Arpicolin).
Anticholinergics are often prescribed alone, especially in the
early stages before levodopa is necessary, although they are also
used in conjunction with levodopa or amantadine. Trihexyphenidyl,
orphenadrine and procyclidine are available in liquid form.
Advantages
They can be useful for younger people in the early stages of
Parkinson's when symptoms are mild. They tend to improve tremor
more than slowness and stiffness. Anticholinergics may also be used
to reduce saliva production when drooling is a problem and to damp
down bladder contractions that can cause a strong, frequent urge to
urinate.
Disadvantages
Confusion, a dry mouth, constipation and blurring of vision can
occur. They are not usually prescribed to older people with
Parkinson's because there is an increased risk of confusion as well
as memory loss, and in men, urinary hesitancy. Also,
anticholinergics may interfere with levodopa absorption in the
small bowel. This can reduce the effectiveness of Sinemet or
Madopar.
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