(FDA approved in bold)

• Extrapyramidal disorders
  
• Parkinsonism
  
• Idiopathic generalized dystonia
  
• Focal dystonias
  
• Dopa-responsive dystonia

• In PD, there is a relative excess of cholinergic input. Trihexyphenidyl is a synthetic anticholinergic with relatively greater CNS activity than most other anticholinergics
  
• May also inhibit the reuptake and storage of dopamine at dopamine neurons and transporters, prolonging dopamine action

• PD/extrapyramidal disorders – minutes-hours

• PD – do not abruptly discontinue or change doses of other PD treatments. Usually most effective in combination with other medications

• PD – Generally trihexyphenidyl is an adjunctive medication for common PD symptoms, such as tremor, rigidity, and drooling. Other cardinal PD symptoms, such as bradykinesia and gait difficulties, are most likely to improve with other PD treatments, such as levodopa, dopamine agonists, amantadine, or MAO-B inhibitors
  
• Extrapyramidal disorders – increase to highest tolerated dose. Long-standing disorders are less likely to respond to treatment

• For bradykinesia or gait disturbances causing significant functional disturbance, levodopa is most effective. For idiopathic PD patients, especially younger patients with normal cognition and milder disability, dopamine agonists are also a good first choice. Amantadine and MAO-B inhibitors may also be useful
  
• Depression is common in PD and may respond to low-dose SSRIs

• None