trihexyphenidyl ARTANE

Class: Anticholinergic/​Parasympatholytic
FDA Indications: Parkinson's Disease, Drug-induced Extrapyramidal Reactions
Off-Label Use: Psychotic Depression
Prescribing
Forms: 2, 5mg tablet; 2mg/5mL IM
Dose Range: 5-15 mg/day
Starting: EPS: 5-15 mg/day; assess effect and increase dose empirically as tolerated
Parkinsonism: start at 1 mg qd; after 3 days can increase in 2 mg increments q 3-5 days as tolerated until clinical effect is reached; total daily dose should be given t.i.d. a.c.
Stopping: Do not abruptly discontinue. has been reported in association with dose reduction or discontinuation of trexyphenidyl

NAMI drug fact sheet

Precautions
Contraindications: Narrow angle glaucoma
Side Effects: anticholinergic side effects
Pharmacodynamics
1° MOA: Centrally-acting antimuscarinic agent; reinstates balance of dopaminergic to cholinergic activity in the nigrostriatal pathway (as dopaminergic activity ↓ d/t D2-blockade, the anti-ACh aims to likewise ↓ cholineric activity and restore the DA/ACh ratio)
Target: M1
Pharmacokinetics
t½: 3 (3.3-4.1)° TMAX:
Substrate of: Hydroxylation
Inhibits: ∅ ; Induces:
Active Metabolites:
DDIs
  • - caution with co-prescribed CNS depressants which can ↑ sedative effects
  • - can enhance anticholinergic actions of other anticholinergic agents
Misc
  • - there are case reports of abuse for its purported euphoric effect
  • - sedation limits use, especially in older patients
  • - useful adjunct in younger Parkinsonís patients with tremor
  • - can cause cognitive side effects with chronic use, so periodic trials of discontinuation may be useful to justify continuous use, especially in institutional settings as adjunct to antipsychotics
  • - patients with mental impairment do poorly
Special Populations

Category C—The limited human pregnancy experience and the absence of animal reproduction data prevents a better assessment of the embryo-fetal risk. However, in general, anticholinergics are considered low risk in pregnancy.

Limited Human Data—Probably Compatible


Use with caution; elderly patients may be more susceptible to side effects

No known effects, but use with caution


No known effects, but use with caution

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Last updated January 22 2018 19:18:05. Disclaimer: This website does not provide medical advice, nor is it a substitute for clinical judgment.