Complete adverse effect profile including incidence rates and management
Important Safety Information
This is not a complete list of all possible side effects. Contact your healthcare provider if you experience any unexpected symptoms. For serious or life-threatening side effects, seek emergency medical attention immediately.
ADVERSE REACTIONS Minor side effects, such as dryness of the mouth, blurred vision, dizziness, mild nausea or nervousness, will be experienced by 30 to 50 percent of all patients.
These sensations, however, are much less troublesome with trihexyphenidyl than with belladonna alkaloids and are usually less disturbing than unalleviated parkinsonism.
Such reactions tend to become less pronounced, and even to disappear, as treatment continues.
Even before these reactions have remitted spontaneously, they may often be controlled by careful adjustment of dosage form, amount of drug, or interval between doses.
Isolated instances of suppurative parotitis secondary to excessive dryness of the mouth, skin rashes, dilatation of the colon, paralytic ileus, and certain psychiatric manifestations such as delusions, hallucinations, and paranoia, all of which may occur with any of the atropine-like drugs, have been reported rarely with trihexyphenidyl.
Potential side effects associated with the use of any atropine-like drugs, including trihexyphenidyl, include cognitive dysfunctions, including confusion and memory impairment;
constipation, drowsiness, urinary hesitancy or retention, tachycardia, dilation of the pupil, increased intraocular pressure, choreiform movements, weakness, vomiting, and headache.
Exacerbation of parkinsonism with abrupt treatment withdrawal has been reported.
Neuroleptic malignant syndrome with abrupt treatment withdrawal has been reported (See WARNINGS, Neuroleptic Malignant Syndrome ).
The occurrence of angle-closure glaucoma in patients receiving trihexyphenidyl has been reported (blindness has been reported in some cases).
WARNINGS Patients to be treated with trihexyphenidyl should have a gonioscope evaluation prior to initiation of therapy and close monitoring of intraocular pressures.
The use of anticholinergic drugs may precipitate angle closure with an increase in intraocular pressure.
If blurring of vision occurs during therapy, the possibility of narrow angle glaucoma should be considered.
Blindness has been reported due to aggravation of narrow angle glaucoma.
(See CONTRAINDICATIONS and ADVERSE REACTIONS ).
Like all medications, Trihexyphenidyl Hydrochloride can cause side effects. However, not everyone who takes this medication will experience them. Many side effects are dose-dependent and may improve as your body adjusts to the medication. Others may require dose adjustment or medical attention.
Contact your healthcare provider promptly if you experience:
Seek immediate emergency medical care if you experience signs of: