Trihexyphenidyl Side Effects
Medically reviewed by Drugs.com. Last updated on Nov 24, 2022.
Applies to trihexyphenidyl: oral elixir, oral tablet.
Serious side effects of Trihexyphenidyl
Along with its needed effects, trihexyphenidyl may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking trihexyphenidyl:
- Abdominal or stomach cramps or pain
- delusions of persecution, mistrust, suspiciousness, or combativeness
- excessive dryness of the mouth
- false beliefs that cannot be changed by facts
- loss of appetite
- nausea or vomiting
- seeing, hearing, or feeling things that are not there
- skin rash
- stomach pain
- swollen, painful, or tender lymph glands on the side of the face or neck
Incidence not known
- blurred vision
- change in vision
- decrease in frequency of urination
- decrease in urine volume
- difficult urination
- difficulty in passing urine (dribbling)
- disturbed behavior
- dry mouth
- enlarged pupils
- eye pain
- fast, pounding, or irregular heartbeat or pulse
- loss of vision
- mental confusion
- painful urination
- shortness of breath
- trouble sleeping
Other side effects of Trihexyphenidyl
Some side effects of trihexyphenidyl may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- mild nausea
Incidence not known
For Healthcare Professionals
Applies to trihexyphenidyl: oral elixir, oral tablet.
The most commonly reported adverse reactions have included dry mouth, blurred vision, dizziness, nausea, and nervousness.[Ref]
Rare (less than 0.1%): Suppurative parotitis, dilation of colon, paralytic ileus
Isolated cases of suppurative parotitis secondary to excessive dryness of the mouth have been reported.[Ref]
Frequency not reported: Drowsiness, headache, choreiform movements, neuroleptic malignant syndrome (with abrupt discontinuation), paraesthesia, numbness of fingers and dyskinesia, chorea, dizziness[Ref]
Toxic psychosis, when present, tends to occur quickly, generally within several days to a week of initiating therapy or within hours after an acute overdose. However, occasionally the onset may be delayed by months. Symptoms generally resolve spontaneously within a few days after the discontinuation of medication.
Psychiatric deterioration and psychotic flare-ups have also been reported following withdrawal of therapy. Symptoms include delusions, hallucinations, aggression or violent behavior, and suicidal tendencies. In high dosages, it may produce euphorigenic effects. For this reason, it can be a drug of abuse.[Ref]
Rare (less than 0.1%): Delusions, hallucinations, paranoia
Frequency not reported: Nervousness, restlessness, euphoria, unusual excitement, impairment of memory or forgetfulness, confusion or delirium, psychiatric deterioration and psychotic flare-ups, toxic psychosis, depression, anxiety, agitation, insomnia[Ref]
Frequency not reported: Allergic reaction, hypersensitivity
Rare (less than 0.1%): Skin rash
Frequency not reported: Anhidrosis, dry skin
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- Drug class: anticholinergic antiparkinson agents
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Related treatment guides
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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.