This information is for people who have Parkinson's disease. It tells you about anticholinergic drugs, a treatment used for Parkinson's.
We haven't looked at the research on anticholinergic drugs in the same detail we have for the other treatments we cover. (For more, see Our method.) But we wanted to include some information because you may be interested.
What are they?
Anticholinergic drugs block the activity of a substance in the body called acetylcholine. Like dopamine, acetylcholine is a neurotransmitter. It carries messages between nerve cells. But it doesn't play a big role in Parkinson's.
Until drugs were discovered that work on dopamine, anticholinergic drugs were used quite a lot to treat Parkinson's. Now, they tend to be used early on in Parkinson's so you don't need to use levodopa so soon. 
They work better at treating tremor than they do for the other symptoms of Parkinson's.   They also help to treat muscle spasms in the foot in people who get Parkinson's at a young age. 
Anticholinergic drugs are also used to treat people who have developed Parkinson's after taking certain antipsychotics. Antipsychotics are used to treat schizophrenia and sometimes other mental illnesses.
Anticholinergic drugs used in the UK are: 
procyclidine (brand names Arpicolin and Kemadrin)
orphenadrine (brand names Biorphen and Disipal)
trihexyphenidyl (also called benzhexol) (brand name Broflex)
benzatropine (brand name Cogentin).
These drugs can cause the following side effects:
Some people become confused and find it hard to concentrate when they take anticholinergic drugs. For this reason they need to be used very carefully in older people who may already have some memory and other neurological problems. 
Glaucoma is a condition that affects the eyes. If you have glaucoma, your vision slowly gets worse. It happens when certain nerves in your head get damaged. These nerves carry images of what you see to your brain. Glaucoma is often caused by high pressure inside your eye.
Neurotransmitters are chemicals that help to carry messages between nerve cells. Serotonin, dopamine, and norepinephrine (noradrenaline) are all neurotransmitters.
Schizophrenia is a mental illness that causes delusions and hallucinations.
For more terms related to Parkinson's disease
For references related to Parkinson's disease click here