Trihexyphenidyl is an anticholinergic medication primarily used to manage symptoms of Parkinson’s disease and certain types of movement disorders. Here’s a brief overview:

Uses:

  1. Parkinson’s Disease: Helps control tremors, rigidity, and excessive salivation.
  2. Drug-Induced Extrapyramidal Symptoms: Treats side effects from antipsychotic medications, such as dystonia and akathisia.

Mechanism of Action:

It blocks acetylcholine receptors in the central nervous system, restoring the balance between dopamine and acetylcholine, which is often disrupted in Parkinson’s disease.

Dosage:

  • Typically starts at a low dose (1–2 mg daily) and is gradually increased based on response and tolerance.
  • The maximum dose is usually around 6–10 mg per day, divided into multiple doses.

Side Effects:

  • Common: Dry mouth, Blurred vision, Constipation, Dizziness, Urinary retention.
  • Serious: Confusion, Hallucinations, Memory problems and  Increased risk of falls (especially in the elderly).

Precautions

  • Use with caution in elderly patients due to increased sensitivity to anticholinergic effects.
  • Avoid in patients with glaucoma, urinary retention, or gastrointestinal obstruction.
  • May worsen symptoms of dementia or cognitive impairment.

Interactions

  • Can interact with other anticholinergic drugs, increasing the risk of side effects.
  • May reduce the effectiveness of medications like donepezil or rivastigmine (used for Alzheimer’s disease).

Important Notes

  • Do not stop using this medication suddenly, as it may cause withdrawal symptoms.
  • Regular monitoring is required to assess effectiveness and side effects.

Always consult a healthcare provider for personalized advice and dosing.