Dosing & Uses
Dosage Forms & 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
Drug-induced Extrapyramidal Symptoms
1 mg/day PO initially; increase as necessary to maintenance range of 5-15 mg/day PO divided q6-8hr
Safety and efficacy not established
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
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
>10%
Anticholinergic side effects (30-50%)
Rash
<1%
Suppurative parotitis
Hallucination
Paralytic ileus
Warnings
Contraindications
Hypersensitivity
Angle-closure glaucoma
Cautions
Exacerbation of parkinsonism, neuroleptic malignant syndrome, and withdrawal symptoms associated with therapy discontinuation or dose reduction; drug should be withdrawn gradually
Perform gonioscope evaluation before initiating treatment; monitor intraocular pressure closely at regular periodic intervals
Therapy may impair memory and exacerbate cognitive deficits in the elderly; may also cause delirium, hallucinations, and confusion when administered at high doses
Use extreme caution and monitor closely patients with liver, cardiac, kidney disorders, prostatic hyperplasia (urinary stricture), or with hypertension
Drug has atropine-like properties; use with caution in patients with glaucoma, obstructive disease of the gastrointestinal or genitourinary tracts and in elderly males with prostatic hypertrophy
Geriatric patients (>60 years) develop increased sensitivity to parasympathetic drugs; may precipitate incipient glaucoma in these patients
Not for use in patients with tardive dyskinesia unless it exists concomitantly with Parkinson disease; therapy may potentially exacerbate symptoms of tardive dyskinesia
May cause hyperthermia that can be fatal and anhidrosis; use with caution during exercise or hot weather, especially if administered concomitantly with anticholinergic agents to patients with CNS disease, alcoholics, or persons in a hot environment doing manual labor
Pregnancy & 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
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
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Patient Handout
Formulary
Adding plans allows you to compare formulary status to other drugs in the same class.
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Adding plans allows you to:
- View the formulary and any restrictions for each plan.
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- Compare formulary status to other drugs in the same class.
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