Anti-cholinergics

Key Facts

  • Anti-cholinergics are most useful in young people with tremor-predominant PD, though side effects may limit their usefulness.
  • Anti-cholinergics should be used with caution in those older than 60 years due to risk of confusion.

It is believed that acetylcholine and dopamine maintain a delicate equilibrium in the normal brain, which is upset by the depletion of dopamine and the degeneration of dopamine-producing cells. Therefore, drugs that block the effect of acetylcholine have the potential for restoring the normal balance of these two chemicals, thereby reducing the symptoms of PD.  

 

 Presentation

Dosages in Milligrams

Typical Treatment Regimens

Indications for Usage

Trihexyphenidyl (formerly Artane®)

2, 5

1-2 mg 2 or 3 times daily

Monotherapy or adjunct therapy, predominantly for tremor in younger people

Benztropine (Cogentin®)

0.5, 1, 2

0.5–2 mg 2 or 3 times daily

Same as above

 
  • Procyclidine (not available in the US)
  • Ethopropazine (a phenothiazine with atropine-like effects) 50 mg

Prescription Recommendations

Trihexyphenidyl

  • Prescribe 1-2 mg bid or tid
  • Good for refractory tremor but may result in anticholinergic side effects
  • Watch especially for cognitive issues

Benztropine

  • Prescribe 0.5–2 mg bid or tid
  • Improvement may not be readily evident within the first 2 days
  • Good for refractory tremor but may result in anticholinergic side effects
  • Watch especially for cognitive issues

Side Effects

  • Drowsiness
  • Dry mouth
  • Difficulty urinating
  • Constipation
References: 

Ahlskog JE. Parkinson’s Disease Treatment Guide fro Physicians. New York, NY: Oxford University Press,;2009.

Ahlskog JE. The Parkinson’s Disease Treatment Book: Partnering with Your Doctor to Get the Most from Your Medications. New York, NY: Oxford University Press; 2005.