What Are Anticholinergics?

Reviewed by: HU Medical Review Board | Last reviewed: April 2022

Anticholinergics are a class of drugs used to treat the symptoms of Parkinson’s disease (PD), particularly the tremor that is a key feature of PD.1,2

Anticholinergics were the first pharmaceutical drugs used to treat PD. However, they are not as effective in reducing the motor symptoms of the condition compared to other treatments like carbidopa-levodopa therapy and dopamine agonists. Anticholinergics may be used as an additional treatment to help relieve the tremor of PD. They are typically used in younger people with PD due to side effects.1,2

How do anticholinergics work?

The motor symptoms of PD are caused by the reduction in dopamine. This is a neurotransmitter (chemical messenger) that sends signals in the brain to produce smooth, purposeful movement. As PD damages and destroys the nerve cells that make dopamine, the motor symptoms of PD appear.1,2

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The primary treatments for PD directly affect dopamine. However, anticholinergics work in a different way to treat the symptoms of PD. They block the action of acetylcholine. This is another neurotransmitter involved in messages from the brain to the muscles. Anticholinergics work on correcting an imbalance between acetylcholine and dopamine in an area of the brain. Anticholinergics are often used in along with other treatments for PD.1,2

Examples of anticholinergics

The 2 anticholinergics used in the United States to treat PD include:3-5

  • Cogentin® (benzotropine mesylate)
  • Trihexyphenidyl

Cogentin comes in a tablet and an injectable form, but the tablet is most often used for people with PD. Artane comes in a tablet and an elixir.3-5

What are the possible side effects of anticholinergics?

Side effects can vary depending on the specific drug you are taking. The most common side effects of anticholinergic drugs include:3

People over the age of 70 taking anticholinergics are more likely to experience side effects of:3

These are not all the possible side effects of anticholinergics. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with anticholinergics.

Things to know about anticholinergics

Before beginning treatment for Parkinson's disease, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

Additional therapy

Anticholinergics are just 1 category of drugs used in the treatment of PD. There are several other types of treatment for the symptoms of PD, including:6

Each person with PD experiences a unique set of symptoms and progression of the disease. Treatments are determined based on each person's specific symptoms and how they respond to different drugs.6