Trihexyphenidyl hydrochloride is an anticholinergic agent that exerts a direct inhibitory effect on the parasympathetic nervous system. It also produces a relaxing effect on smooth muscles, acting both directly on muscle tissue and indirectly through parasympathetic inhibition. These actions help reduce muscle rigidity, tremor, and involuntary movements associated with parkinsonism and drug-induced extrapyramidal symptoms.

Indications

Trihexyphenidyl HCl tablets are indicated for:

• Adjunctive treatment of all forms of parkinsonism, including post-encephalitic, arteriosclerotic, and idiopathic Parkinson’s disease

• Control of extrapyramidal disorders caused by central nervous system drugs such as dibenzoxazepines, phenothiazines, thioxanthenes, and butyrophenones

  রেজিস্টার্ড চিকিৎসকের পরামর্শ অনুযায়ী ঔষধ সেবন করুন

Dosage & Administration

Dosage should be individualized based on patient response and tolerance. Treatment should be initiated at a low dose and increased gradually, particularly in patients over 60 years of age. The timing of administration before or after meals depends on individual patient response.

Idiopathic Parkinsonism:

• Initial dose: 1 mg on the first day

• Dose may be increased by 2 mg increments at intervals of 3–5 days

Drug-Induced Parkinsonism:

• Start with 1 mg daily

• Total daily dose may be increased to 5–15 mg if extrapyramidal symptoms are not adequately controlled

Concomitant Use with Levodopa:

• Usual daily dose ranges from 3–6 mg

All dosing adjustments should be made under medical supervision.

Side Effects

Commonly reported side effects are generally mild and may include:

• Dry mouth

• Blurred vision

• Dizziness

• Mild nausea

• Nervousness

Other potential side effects include constipation, drowsiness, urinary hesitancy or retention, pupil dilation, increased intraocular pressure, vomiting, headache, and confusion. Patients with arteriosclerosis or a history of sensitivity to other drugs may experience agitation, disturbed behavior, or mental confusion.

Precautions

• Patients with cardiac, hepatic, or renal disorders, or with hypertension, should be closely monitored

• Use with caution in patients with glaucoma, gastrointestinal or genitourinary obstruction, and in elderly males with possible prostatic hypertrophy

• Not recommended for patients with tardive dyskinesia unless associated with Parkinson’s disease

• Abrupt discontinuation may lead to worsening of parkinsonism symptoms and should be avoided

Use in Pregnancy & Lactation

Pregnancy:
Trihexyphenidyl is classified as Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Lactation:
It is not known whether trihexyphenidyl is excreted in human breast milk. Caution is advised, and the drug should be used only if the expected benefit to the mother outweighs the potential risk to the infant.

রেজিস্টার্ড চিকিৎসকের পরামর্শ অনুযায়ী ঔষধ সেবন করুন

Drug Interactions

• Alcohol, cannabinoids, barbiturates, and opiates may have additive central nervous system depressant effects

• Concomitant use with other CNS depressants may increase sedation

• Use with monoamine oxidase inhibitors and tricyclic antidepressants may be contraindicated

Overdose

Overdose with trihexyphenidyl may result in symptoms typical of central anticholinergic toxicity, including dilated pupils, warm and dry skin, facial flushing, reduced secretions, tachycardia, and foul-smelling breath. Neuropsychiatric manifestations such as anxiety, delirium, hallucinations, disorientation, and agitation may occur. Severe cases can progress to stupor, coma, paralysis, cardiac or respiratory arrest, and death.

Storage

Store below 30°C. Protect from light. Keep out of the reach of children.