Generic Name
Trihexyphenidyl HydrochlorideTherapeutic Class: Drugs of Nervous System
Indications:
Trihexyphenidyl HCl tablets are indicated as an adjunct treatment of all forms of parkinsonism (postencephalitic, arteriosclerotic & idiopathic). Additionally, it is indicated for the control of extrapyramidal disorders caused by central nervous system drugs such as dibenzoxazepines, phenothiazines, thioxanthenes & butyrophenones.
Presentation
Trihexyphenidyl Hydrochloride 1: Each tablet contains Trihexyphenidyl Hydrochloride USP 1 mg tablet.
Trihexyphenidyl Hydrochloride 2: Each tablet contains Trihexyphenidyl Hydrochloride USP 2 mg tablet.
Trihexyphenidyl Hydrochloride5: Each tablet contains Trihexyphenidyl Hydrochloride USP 5 mg tablet.
Trihexyphenidyl Hydrochloride Syrup: Each 5 ml syrup contains Trihexyphenidyl Hydrochloride USP 2 mg.
Description:
Trihexyphenidyl exerts a direct inhibitory effect upon the parasympathetic nervous system. It also has a relaxing effect on smooth musculature; exerted both directly upon the muscle tissue itself and indirectly through an inhibitory effect upon the parasympathetic nervous system.
Dosage & Administration:
Dosage should be individualized. The initial dose should be low and then increased
gradually. Should be taken with food. Total daily intake of Trihexyphenidyl Hydrochloride tablets is tolerated best in divided doses.
Idiopathic Parkinsonism: As initial therapy for Parkinsonism, 1 mg of Trihexyphenidyl
hydrochloride in the tablet may be administered the first day. The dose may then be
increased by 2 mg increments at intervals of three to five days. Until a total of 6 to 10
mg is given daily.
Drug-induced Parkinsonism: Initial therapy 1 mg. The total daily dosage usually ranges
between 5 and 15mg. Subsequent doses may be progressively increased until
satisfactory control is achieved.
Concomitant use with Levodopa: When Trihexyphenidyl is used concomitantly with
levodopa; the usual dose of each may need to be reduced. Careful adjustment is
necessary, depending on the side effects and degree of symptom control. 3 to 6 mg
daily in divided doses is usually adequate.
Concomitant use with other Parasympathetic Inhibitors: The total daily intake of
Trihexyphenidyl Hydrochloride tablets are tolerated best if divided into 3 doses and
taken at mealtimes. High doses (10 mg daily) may be divided into 4 parts, with 3
doses administered at mealtimes and the fourth at bedtime.
Post encephalitic Parkinsonism: usually 12 to 15 mg.
Trihexyphenidyl HCl tablets are indicated as an adjunct treatment of all forms of parkinsonism (postencephalitic, arteriosclerotic & idiopathic). Additionally, it is indicated for the control of extrapyramidal disorders caused by central nervous system drugs such as dibenzoxazepines, phenothiazines, thioxanthenes & butyrophenones.
Presentation
Trihexyphenidyl Hydrochloride 1: Each tablet contains Trihexyphenidyl Hydrochloride USP 1 mg tablet.
Trihexyphenidyl Hydrochloride 2: Each tablet contains Trihexyphenidyl Hydrochloride USP 2 mg tablet.
Trihexyphenidyl Hydrochloride5: Each tablet contains Trihexyphenidyl Hydrochloride USP 5 mg tablet.
Trihexyphenidyl Hydrochloride Syrup: Each 5 ml syrup contains Trihexyphenidyl Hydrochloride USP 2 mg.
Description:
Trihexyphenidyl exerts a direct inhibitory effect upon the parasympathetic nervous system. It also has a relaxing effect on smooth musculature; exerted both directly upon the muscle tissue itself and indirectly through an inhibitory effect upon the parasympathetic nervous system.
Dosage & Administration:
Dosage should be individualized. The initial dose should be low and then increased
gradually. Should be taken with food. Total daily intake of Trihexyphenidyl Hydrochloride tablets is tolerated best in divided doses.
Idiopathic Parkinsonism: As initial therapy for Parkinsonism, 1 mg of Trihexyphenidyl
hydrochloride in the tablet may be administered the first day. The dose may then be
increased by 2 mg increments at intervals of three to five days. Until a total of 6 to 10
mg is given daily.
Drug-induced Parkinsonism: Initial therapy 1 mg. The total daily dosage usually ranges
between 5 and 15mg. Subsequent doses may be progressively increased until
satisfactory control is achieved.
Concomitant use with Levodopa: When Trihexyphenidyl is used concomitantly with
levodopa; the usual dose of each may need to be reduced. Careful adjustment is
necessary, depending on the side effects and degree of symptom control. 3 to 6 mg
daily in divided doses is usually adequate.
Concomitant use with other Parasympathetic Inhibitors: The total daily intake of
Trihexyphenidyl Hydrochloride tablets are tolerated best if divided into 3 doses and
taken at mealtimes. High doses (10 mg daily) may be divided into 4 parts, with 3
doses administered at mealtimes and the fourth at bedtime.
Post encephalitic Parkinsonism: usually 12 to 15 mg.
Side Effects:
Minor side effects such as dryness of the mouth, blurring of vision, dizziness, mild nausea, or nervousness. Patients with arteriosclerosis or with a history of idiosyncrasy to other drugs may exhibit reactions of mental confusion, agitation, disturbed behavior, or nausea and vomiting. Potential side effects are constipation, drowsiness, urinary hesitancy or retention, pupil dilation, increased intraocular tension, vomiting, and headache.
Precautions:
Patients with cardiac, liver, or kidney disorders, or with hypertension, should closely be monitored. Since trihexyphenidyl has parasympatholytic activity, it should be used with caution in patients with glaucoma, obstructive disease of the gastrointestinal or genitourinary tracts, and in elderly males with possible prostatic hypertrophy. Trihexyphenidyl is not recommended for use in patients with tardive dyskinesia unless they have concomitant Parkinson’s disease. Abrupt withdrawal of treatment for parkinsonism may result in acute exacerbation of parkinsonism symptoms; therefore, abrupt withdrawal should be avoided.
Use in Pregnancy & Lactation:
Pregnancy: Pregnancy Category C.
Nursing mothers: It is not known whether the drug is excreted in human milk and therefore trihexyphenidyl should only be used if the expected benefit to the mother outweighs the potential risk to the infant.
Interaction:
Cannabinoids, barbiturates, opiates, and alcohol may have additive effects with trihexyphenidyl, and thus, an abuse potential exists. Concurrent use of alcohol or other CNS depressants with trihexyphenidyl may cause increased sedative effects. It may be contraindicated in patients taking monoamine oxidase inhibitors & tricyclic antidepressants.
Overdose:
Overdosage with trihexyphenidyl produces typical central symptoms of atropine intoxication ( the central anticholinergic syndrome). Signs & symptoms are dilated and sluggish pupils, warm, dry skin, facial flushing, decreased secretions of mouth, pharynx, nose, and bronchi, foul-smelling breath, tachycardia, etc. Neuropsychiatric signs such as delirium, disorientation, anxiety, hallucinations, etc. The condition can progress to stupor, coma, paralysis, cardiac, respiratory arrest, and death.
Cannabinoids, barbiturates, opiates, and alcohol may have additive effects with trihexyphenidyl, and thus, an abuse potential exists. Concurrent use of alcohol or other CNS depressants with trihexyphenidyl may cause increased sedative effects. It may be contraindicated in patients taking monoamine oxidase inhibitors & tricyclic antidepressants.
Overdose:
Overdosage with trihexyphenidyl produces typical central symptoms of atropine intoxication ( the central anticholinergic syndrome). Signs & symptoms are dilated and sluggish pupils, warm, dry skin, facial flushing, decreased secretions of mouth, pharynx, nose, and bronchi, foul-smelling breath, tachycardia, etc. Neuropsychiatric signs such as delirium, disorientation, anxiety, hallucinations, etc. The condition can progress to stupor, coma, paralysis, cardiac, respiratory arrest, and death.
Storage:
Protect from light and moisture, store below 30º C. Keep out of the reach of children.
Protect from light and moisture, store below 30º C. Keep out of the reach of children.