Dosing and uses of Artane, Trihex (trihexyphenidyl)
Adult dosage forms and strengths
tablets
- 2mg
- 5mg
elixir
- 0.4mg/mL
Parkinson Disease
Initial: 1 mg PO first day, then increase by 2 mg q3-5days until reach 6-10 mg/days
Maintenance: 5-15 mg/day PO divided q6-8hr
Use SR product once stabilized on regular release product; when used with levodopa, generally use 3-6 mg/day in divided doses
Do not crush SR product
Monitor: IOp
Parkinsonism
5-15 mg/day PO divided q6-8hr
Drug-induced Extrapyramidal Symptoms
5-15 mg/day PO divided q6-8hr
Pediatric dosage forms and strengths
Safety and efficacy not established
Geriatric dosage forms and strengths
Nonanticholinergic antiparkinson agents should be considered first when treating Parkinson Disease (Beers Criteria)
Not recommended for preventing extrapyramidal symptoms
Parkinsonism
5-15 mg/day PO divided q6-8hr
Artane, Trihex (trihexyphenidyl) adverse (side) effects
>10%
Anticholinergic side effects (30-50%)
Rash
<1%
Suppurative parotitis
Hallucination
Paralytic ileus
Warnings
Contraindications
Hypersensitivity
Angle-closure glaucoma
Cardiovascular disease
Cautions
GI obstruction, urinary retention, myasthenia gravis, hypotension, BPH, hepatic/renal impairment
Pregnancy and lactation
Pregnancy category: C
Lactation: no data; may inhibit lactation
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Artane, Trihex (trihexyphenidyl)
Mechanism of action
Trihexyphenidyl inhibits the parasympathetic nervous system and has a relaxing effect on smooth muscles
Pharmacokinetics
Half-Life elimination: 33 hr
Onset: 1 hr
Peak effects: 1.3 hr
Duration: 6-12 hr
Metabolism: Unknown
Excretion: Urine and bile
