II. Indications

  1. Parkinsonism (Idiopathic, Drug-Induced)
    1. Adjunctive, symptomatic management of Tremor or Drooling

III. Contraindications

  1. Narrow Angle Glaucoma
  2. Acute Bowel Obstruction
  3. Megacolon
  4. Elderly (relative)
    1. On Beer's List, due to risk of Delirium, pscyhosis, Fall Risk

IV. Mechanism

  1. Centrally acting Muscarinic Antagonist
  2. Decreases imbalance of Acetylcholine to Dopamine ratio within corpus striatum (Basal Ganglia)

V. Dosing: Parkinsonism

  1. Start 1 mg orally daily
  2. May titrate dose by 2 mg/day weekly
  3. Target 6 to 10 mg/day orally divided three to four times daily
  4. Maximum: 15 mg/day divided 3-4 times daily

VI. Adverse Effects

  1. Anticholinergic Symptoms (Dry Mouth, Constipation, Urinary Retention, altered mentation)
  2. Pregnancy Category C
  3. Unknown safety in Lactation
  4. Withdrawal symptoms with severe increase in Parkinsonism symptoms
    1. Titrate medication off without abruptly stopping

VIII. References

  1. (2021) Med Lett Drugs Ther 63(1618): 25-32
  2. Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 46-7
  3. Hamilton (2020) Tarascon Pocket Pharmacopoeia

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Related Studies

Cost: Medications

trihexyphenidyl (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
TRIHEXYPHENIDYL 2 MG TABLET Generic $0.06 each
TRIHEXYPHENIDYL 2 MG/5 ML SOLN Generic $0.07 per ml
TRIHEXYPHENIDYL 5 MG TABLET Generic $0.10 each

Ontology: Trihexyphenidyl (C0041009)

Definition (MSH) One of the centrally acting MUSCARINIC ANTAGONISTS used for treatment of PARKINSONIAN DISORDERS and drug-induced extrapyramidal movement disorders and as an antispasmodic.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D014282
SnomedCT 2190009, 387120000
LNC LP14553-9, MTHU001575
English Benzhexol, Trihexyphenidyl, trihexyphenidyl, 1-Piperidinepropanol, alpha-cyclohexyl-alpha-phenyl-, Trihexyphenidyl [Chemical/Ingredient], benzhexol, trihexphenidyl, antiparkinsonism drugs trihexyphenidyl, trihexyphenidyl (medication), TRIHEXYPHENIDYL, Trihexyphenidyl (product), Trihexyphenidyl (substance)
Swedish Trihexyfenidyl
Czech trihexyfenidyl
Finnish Triheksifenidyyli
Russian ROMPARKIN, TSIKLODOL, TRIGEKSIFENIDIL, PARKINSAN, BENZIKSOL, PARKOPAN, БЕНЗИКСОЛ, ПАРКИНСАН, ПАРКОПАН, РОМПАРКИН, ТРИГЕКСИФЕНИДИЛ, ЦИКЛОДОЛ
Japanese ベンズヘキソール, 塩酸トリヘキシフェニジル, トリヘキシフェニジル
Italian Benzexolo, Triesifenidile
Polish Artane, Triheksyfenidyl
Spanish trihexifenidilo (producto), trihexifenidilo (sustancia), trihexifenidilo, Benzexol, Trihexifenidilo
French Trihexyphénidyle
German Benzhexol, Trihexyphenidyl
Portuguese Benzexol, Triexifenidil

Ontology: Artane (C0591114)

Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D014282
English Wyeth Brand of Trihexyphenidyl, Trihexyphenidyl Wyeth Brand, AHP Brand of Trihexyphenidyl Hydrochloride, Aventis Brand of Trihexyphenidyl Hydrochloride, Wyeth Brand of Trihexyphenidyl Hydrochloride, Lederle Brand of Trihexyphenidyl Hydrochloride, artane, Artane