Trihexyphenidyl Hydrochloride: Uses, Dosage, Side Effects | MedexInfo

Trihexyphenidyl Hydrochloride

Rx

Generic NameTrihexyphenidyl HCl

Therapeutic ClassAnticholinergic (Antiparkinsonian)

Common Strength2 mg, 5 mg tablet; 2 mg/5 mL syrup

Max / 24h15 mg

PregnancyUse if benefit outweighs risk

Indications ▼

Parkinson’s disease (idiopathic or post-encephalitic)

Drug-induced extrapyramidal symptoms

Antipsychotic-induced parkinsonism and dystonia

Mechanism & Pharmacokinetics ▼

Mechanism: Trihexyphenidyl is a centrally acting anticholinergic that blocks muscarinic receptors in the CNS, restoring the dopamine–acetylcholine balance in the basal ganglia and improving tremor and rigidity.

Pharmacokinetics: Well absorbed orally. Undergoes hepatic metabolism. Duration of action is approximately 6–12 hours. Excretion occurs via urine.

Dosage & Administration ▼

Indication	Dose	Frequency
Parkinson’s disease	1 mg initially, titrated to 6–10 mg	Divided doses daily
Drug-induced extrapyramidal symptoms	2–5 mg	1–3 times daily

Note: Start with low dose and titrate slowly, especially in elderly patients.

Side Effects ▼

Dry mouth

Blurred vision

Constipation

Urinary retention

Dizziness, confusion (elderly)

Rare: hallucinations, psychosis

Contraindications ▼

Narrow-angle glaucoma

Prostatic hypertrophy with urinary retention

Gastrointestinal obstruction

Hypersensitivity to trihexyphenidyl

Drug Interaction ▼

Other anticholinergics: additive adverse effects

Antipsychotics: reduced therapeutic efficacy

CNS depressants: increased sedation

Pregnancy & Lactation ▼

Limited human data; use only if clearly needed

Caution advised during breastfeeding

Clinical / Research Summary ▼

Clinical Role: Useful for tremor-dominant Parkinson’s disease and antipsychotic-induced EPS.

Advantage: Effective for rigidity and tremor.

Limitation: Poor tolerability in elderly due to anticholinergic effects.

Monitoring: Mental status, vision, urinary symptoms.

Patient Counseling Points ▼

Take exactly as prescribed

Avoid driving until response is known

Maintain adequate hydration

Report confusion or vision changes

Storage & Handling ▼

Store below 30°C

Protect from moisture and light

Keep out of reach of children

Brand Names (Bangladesh & Global) ▼

Bangladesh:

Benzhexol® Pacitane® Trihex® Parkin® Trihexy®

Global:

Artane®

Medical Disclaimer: For educational purposes only. Not a substitute for professional medical advice.

Reference Hubs:

• Drug Class: Antiparkinsonian Agents • Condition: Parkinson’s Disease